Trait expectations: Another look at why addictive personality is a complete myth

In the 30 years that I have been carrying out research into addiction, the one question that I have been asked the most – particularly by those who work in the print and broadcast media – is whether there is such a thing as an ‘addictive personality’? In a previous blog I briefly reviewed the concept of ‘addictive personality’ but since publishing that article, I have published a short paper in the Global Journal of Addiction and Rehabilitation Medicine on addictive personality, and in this blog I review I outline some of the arguments as to why I think addictive personality is a complete myth.

Psychologists such as Dr. Thomas Sadava have gone as far to say that ‘addictive personality’ is theoretically necessary, logically defensible, and empirically supportable. Sadava argued that if ‘addictive personality’ did not exist then every individual would vulnerable to addiction if they lived in comparable environments, and that those who were addicted would differ only from others in the specifics of their addiction (e.g., alcohol, nicotine, cocaine, heroin). However, Sadava neglected genetic/biological predispositions and the structural characteristics of the substance or behaviour itself.

There are many possible reasons why people believe in the concept of ‘addictive personality’ including the facts that: (i) vulnerability is not perfectly correlated to one’s environment, (ii) some addicts are addicted to more than one substance/activity (cross addiction) and engage themselves in more than one addictive behaviour, and (iii) on giving up addiction some addicts become addicted to another (what I and others have referred to as ‘reciprocity’). In all the papers I have ever read concerning ‘addictive personality’, I have never read a good operational definition of what ‘addictive personality’ actually is (beyond the implicit assumption that it refers to a personality trait that helps explain why individuals become addicted to substances and/or behaviours). Dr. Craig Nakken in his book The Addictive Personality: Understanding the Addictive Process and Compulsive Behaviour argued that ‘addictive personality’ is “created from the illness of addiction”, and that ‘addictive personality’ is a consequence of addiction and not a predisposing factor. In essence, Nakken simply argued that ‘addictive personality’ refers to the personality of an individual once they are addicted, and as such, this has little utility in understanding how and why individuals become addicted.

When teaching my own students about the concept of ‘addictive personality’ I always tell them that operational definitions of constructs in the addictive behaviours field are critical. Given that I have never seen an explicit definition of ‘addictive personality’ I provide my own definition and argue that ‘addictive personality’ (if it exists) is a cognitive and behavioural style which is both specific and personal that renders an individual vulnerable to acquiring and maintaining one or more addictive behaviours at any one time. I also agree with addiction experts that the relationship between addictive characteristics and personality variables depend on the theoretical considerations of personality. According to Dr. Peter Nathan there must be ‘standards of proof’ to show valid associations between personality and addictive behaviour. He reported that for the personality trait or factor to genuinely exist it must: (i) either precede the initial signs of the disorder or must be a direct and lasting feature of the disorder, (ii) be specific to the disorder rather than antecedent, coincident or consequent to other disorders/behaviours that often accompany addictive behaviour, (iii) be discriminative, and (iv) be related to the addictive behaviour on the basis of independently confirmed empirical, rather than clinical, evidence. As far as I am aware, there is no study that has ever met these four standards of proof, and consequently I would argue on the basis of these that there is no ‘addictive personality’.

Although I do not believe in the concept of ‘addictive personality’ this does not mean that personality factors are not important in the acquisition, development, and maintenance of addictive behaviours. They clearly are. For instance, a paper in the Psychological Bulletin by Dr. Roman Kotov and his colleagues examined the associations between substance use disorders (SUDs) and higher order personality traits (i.e., the ‘big five’ of openness to experience, conscientiousness, agreeableness, extraversion, and neuroticism) in 66 meta-analyses. Their review included 175 studies (with sample sizes ranged from 1,076 to 75,229) and findings demonstrated that SUD addicts were high on neuroticism (and was the strongest personality trait associated with SUD addiction) and low on conscientiousness. Many of the studies the reviewed also reported that agreeableness and openness were largely unrelated to SUDs.

Dr. John Malouff and colleagues carried published a meta-analysis in the Journal of Drug Education examining the relationship between the five-factor model of personality and alcohol. The meta-analysis included 20 studies (n=7,886) and showed alcohol involvement was associated with low conscientiousness, low agreeableness, and high neuroticism. Mixed-sex samples tended to have lower effect sizes than single-sex samples, suggesting that mixing sexes in data analysis may obscure the effects of personality. Dr. James Hittner and Dr. Rhonda Swickert published a meta-analysis in the journal Addictive Behaviors examining the association between sensation seeking and alcohol use. An analysis of 61 studies revealed a small to moderate size heterogeneous effect between alcohol use and total scores on the sensation seeking scale. Further analysis of the sensation seeking components indicated that disinhibition was most strongly correlated with alcohol use.

Dr. Marcus Munafo and colleagues published a meta-analysis in the journal Nicotine and Tobacco Research examining strength and direction of the association between smoking status and personality. They included 25 cross-sectional studies that reported personality data for adult smokers and non-smokers and reported a significant difference between smokers and non-smokers on both extraversion and neuroticism traits. In relation to gambling disorder, Dr. Vance MacLaren and colleagues published a meta-analysis of 44 studies that had examined the personality traits of pathological gamblers (N=2,134) and non-pathological gambling control groups (N=5,321) in the journal Clinical Psychology Review. Gambling addiction was shown to be associated with urgency, premeditation, perseverance, and sensation seeking aspects of impulsivity. They concluded that individual personality characteristics may be important in the aetiology of pathological gambling and that the findings were similar to the meta-analysis of substance use disorders by Kotov and colleagues.

More recently, I co-authored a study with Dr. Cecilie Andreassen and her colleagues in the Journal of Behavioral Addictions. We carried out the first ever study investigating the inter-relationships between the ‘big five’ personality traits and behavioural addictions. They assessed seven behavioural addictions (i.e., Facebook addiction, video game addiction, Internet addiction, exercise addiction, mobile phone addiction, compulsive buying, and study addiction). Of 21 inter-correlations between the seven behavioural addictions, all were positive (and nine significantly so). More specifically: (i) neuroticism was positively associated with Internet addiction, exercise addiction, compulsive buying, and study addiction, (ii) extroversion was positively associated with Facebook addiction, exercise addiction, mobile phone addiction, and compulsive buying, (iii) openness was negatively associated with Facebook addiction and mobile phone addiction, (iv) agreeableness was negatively associated with Internet addiction, exercise addiction, mobile phone addiction, and compulsive buying, and (v) conscientiousness was negatively associated with Facebook addiction, video game addiction, Internet addiction, and compulsive buying and positively associated with exercise addiction and study addiction. However, replication and extension of these findings is needed before any definitive conclusions can be made.

Overall these studies examining personality and addiction consistently demonstrate that addictive behaviours are correlated with high levels of neuroticism and low levels of conscientiousness. However, there is no evidence of a single trait (or set of traits) that is predictive of addiction, and addiction alone. Others have also reached the same conclusion based on the available evidence. For instance, R.G. Pols (in Australian Drug/Alcohol Review) noted that findings from prospective studies are inconsistent with retrospective and cross-sectional studies leading to the conclusion that the ‘addictive personality’ is a myth. Dr. John Kerr in the journal Human Psychopharmacology: Clinical and Experimental noted that ‘addictive personality’ had long been argued as a viable construct (particularly in the USA) but that there is simply no evidence for the existence of a personality type that is prone to addiction. In another review of drug addictions, Kevin Conway and colleagues asserted (in the journal Drug and Alcohol Dependence) there was scant evidence that personality traits were associated with psychoactive substance choice. Most recently, Maia Szalavitz in her book Unbroken Brain: A Revolutionary New Way of Understanding Addiction noted that:

“Fundamentally, the idea of a general addictive personality is a myth. Research finds no universal character traits that are common to all addicted people. Only half have more than one addiction (not including cigarettes)—and many can control their engagement with some addictive substances or activities, but not others”.

Clearly there are common findings across a number of differing addictions (such as similarities in personality profiles using the ‘big five’ traits) but it is hard to establish whether these traits are antecedent to the addiction or caused by it. Within most addictions there appear to be more than one sub-type of addict suggesting different pathways of how and way individuals might develop various addictions. If this is the case – and I believe that it is – where does that leave the ‘addictive personality’ construct?

‘Addictive personality’ is arguably a ‘one type fits all’ approach and there is now much evidence that the causes of addiction are biopsychosocial from an individual perspective, and that situational determinants (e.g., accessibility to the drug/behaviour, advertising and marketing, etc.) and structural determinants (e.g., toxicity of a specific drug, game speed in gambling, etc.) can also be influential in the aetiology of problematic and addictive behaviours. Another problem with ‘addictive personality’ being an explanation for why individuals develop addictions is that the concept inherently absolves an individual’s responsibility of developing an addiction and puts the onus on others in treating the addiction. Ultimately, all addicts have to take some responsibility in the development of their problematic behaviour and they have to take some ownership for overcoming their addiction. Personally, I believe it is better to concentrate research into risk and protective factors of addiction rather than further research of ‘addictive personality’.

As I have argued in a number of my papers and book chapters, not every addict has a personality disorder, and not every person with a personality disorder has an addiction. While some personality disorders appear to have an association with addiction including Antisocial Personality Disorder and Borderline Personality Disorder, just because a person has some of the personality traits associated with addiction does not mean they are, or will become, an addict. Practitioners consider specific personality traits to be warning signs, but that’s all they are. There is no personality trait that guarantees an individual will develop an addiction and there is little evidence for an ‘addictive personality’ that is predictive of addiction alone. In short, ‘addictive personality’ is a complete myth.

Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Andreassen, C.S., Griffiths, M.D., Gjertsen, S.R., Krossbakken, E., Kvan, S., & Ståle Pallesen, S. (2013). The relationships between behavioral addictions and the five-factor model of personality. Journal of Behavioral Addictions, 2, 90-99.

Conway, K. P., Kane, R. J., Ball, S. A., Poling, J. C., & Rounsaville, B. J. (2003). Personality, substance of choice, and polysubstance involvement among substance dependent patients. Drug and Alcohol Dependence, 71(1), 65-75.

Griffiths, M.D. (1994). An exploratory study of gambling cross addictions. Journal of Gambling Studies, 10, 371-384.

Griffiths, M.D. (1996). Behavioural addictions: An issue for everybody? Journal of Workplace Learning, 8(3), 19-25.

Griffiths, M.D. (2005). A ‘components’ model of addiction within a biopsychosocial framework. Journal of Substance Use, 10, 191-197.

Griffiths, M.D. (2009). The psychology of addictive behaviour. In: M. Cardwell, M., L. Clark, C. Meldrum & A. Waddely (Eds.), Psychology for A2 Level (pp. 236-471). London: Harper Collins.

Griffiths, M.D. (2017). The myth of ‘addictive personality’. Global Journal of Addiction and Rehabilitation Medicine, 3(2), 555610.

Hittner, J. B., & Swickert, R. (2006). Sensation seeking and alcohol use: A meta-analytic review. Addictive Behaviors, 31(8), 1383-1401.

Kerr, J. S. (1996). Two myths of addiction: The addictive personality and the issue of free choice. Human Psychopharmacology: Clinical and Experimental, 11(S1), S9-S13.

Kotov, R., Gamez, W., Schmidt, F., & Watson, D. (2010). Linking “big” personality traits to anxiety, depressive, and substance use disorders: a meta-analysis. Psychological Bulletin, 136(5), 768-821.

MacLaren, V. V., Fugelsang, J. A., Harrigan, K. A., & Dixon, M. J. (2011). The personality of pathological gamblers: A meta-analysis. Clinical Psychology Review, 31(6), 1057-1067.

Malouff, J. M., Thorsteinsson, E. B., Rooke, S. E., & Schutte, N. S. (2007). Alcohol involvement and the Five-Factor Model of personality: A meta-analysis. Journal of Drug Education, 37(3), 277-294.

Munafo, M. R., Zetteler, J. I., & Clark, T. G. (2007). Personality and smoking status: A meta-analysis. Nicotine & Tobacco Research, 9(3), 405-413.

Nakken, C. (1996). The addictive personality: Understanding the addictive process and compulsive behaviour. Hazelden, Center City, MN: Hazelden.

Nathan, P. E. (1988). The addictive personality is the behavior of the addict. Journal of Consulting and Clinical Psychology, 56(2), 183-188.

Pols, R. G. (1984). The addictive personality: A myth. Australian Alcohol/Drug Review, 3(1), 45-47.

Sadava, S.W. (1978). Etiology, personality and alcoholism. Canadian Psychological Review/Psychologie Canadienne, 19(3), 198-214.

Szalavitz M (2016). Unbroken brain: A revolutionary new way of understanding addiction. St. Martin’s Press, New York.

Szalavitz M (2016). Addictive personality isn’t what you think it is. Scientific American, April 5.

Group therapy: The psychology of the Beatles

Although I love many musical groups and singers, the Beatles have always been (and always will be) my all-time favourite band. Being an obsessive fan of the group is not cheap because there is almost a never-ending supply of products that can be bought including records, CDs, DVDs, books, and other merchandise such as mugs, t-shirts, coasters, and games. I’m a sucker for it all and as a record collecting completist, I have to have every single track they have ever recorded on both official releases and bootlegs (my latest acquisition being the 6-disc collector’s edition of Sgt. Pepper’s Lonely Hearts Club Band). It’s both fun and expensive (but thankfully I have few vices) and the Beatles are one of the few artists that I have spent thousands and thousands of pounds indulging my passion for their music (others include David Bowie, Adam Ant, The Smiths [and Morrissey], Gary Numan, Velvet Underground [and Lou Reed and John Cale], John Foxx [and Ultravox], Art of Noise [and other ZTT bands], and Iggy Pop [and The Stooges]).

One of the reasons I chose to study psychology at university was because John Lennon underwent primal therapy (a trauma-based psychotherapy) in 1970 with its’ developer (US psychotherapist Dr. Arthur Janov). I read Janov’s first book (The Primal Scream) in 1983 just because of my love of Lennon’s work, and psychology sounded far more interesting than the ‘A’ levels I was doing at the time (maths, physics, chemistry and biology). As the Wikipedia entry on primal therapy notes:

“The musician John Lennon and his wife, Yoko Ono, went through primal therapy in 1970. A copy of the just-released The Primal Scream arrived in the mail at Lennon’s home, Tittenhurst Park (sources differ about who sent the book). Lennon was impressed, and he requested primal therapy to be started at Tittenhurst. Arthur Janov and his first wife, Vivian Janov, went to Tittenhurst in March 1970 to start the therapy, which continued in April in Los Angeles. Arthur Janov went to Tittenhurst after giving instructions in advance about the isolation period and giving instructions to Lennon to be separated from Ono. Lennon and Ono had three weeks of intensive treatment in England before Janov returned to Los Angeles, where they had four months of therapy. According to some sources, Lennon ended primal therapy after four months…Lennon commented after therapy, ‘I still think that Janov’s therapy is great, you know, but I do not want to make it a big Maharishi thing’ and ‘I just know myself better, that’s all. I can handle myself better. That Janov thing, the primal scream and so on, it does affect you, because you recognize yourself in there…It was very good for me. I am still ‘primal’ and it still works.’ and ‘I no longer have any need for drugs, the Maharishi or the Beatles. I am myself and I know why’”.

Lennon didn’t undergo primal therapy until just after the Beatles had split up and it was his 1970 solo LP (John Lennon/Plastic Ono Band) that included many songs that were rotted in his primal therapy experiences including ‘Mother’, ‘My Mummy’s Dead’, ‘God’, ‘Working Class Hero’, ‘Remember’, and ‘Well Well Well’. Many describe this LP as Lennon at his most raw and the album is all the better for it.

At university, one of my favourite topics was Gestalt psychology and its basic tenet that ‘the whole is more than the sum of its parts’ to me encapsulates The Beatles as a whole. John Lennon, Paul McCartney, George Harrison and Ringo Starr were all brilliant in their own musical sphere but little of their best solo work – with the odd exception – was ever as good as the best of their work with the Beatles. For whatever reason, the Beatles working as a foursome – even when the songs had been written individually – produced music as a group that was better than music on their solo LPs. The Beatles early solo recordings (1970-71) included songs that had typically been written while they were still in The Beatles. For instance, many of the songs on George Harrison’s brilliant (and best) album, All Things Must Pass, had been practiced and rehearsed during the making of the Beatles’ final LP Let It Be.

In previous blogs I have looked at celebrities’ use of illicit drugs (one on celebrities in general and whether they are more prone to addiction, one on David Bowie, The Beatles and addiction, and a third one looking at the use of psychoactive substance use on the process of creativity). My first awareness of illicit drugs was reading about the Beatles’ use of various substances in many biographies I read during my early adolescence. When it came to drugs, the Beatles appeared to have seen and done it all. In their pre-fame days in early 1960s Hamburg they all lived on a diet of pills, poppers, and stimulants just to get through their hours of playing every single day. Like many hard working musicians they used a combination of ‘uppers’ and ‘downers’ to regulate their day-to-day living. By the mid-1960s they were all smoking marijuana and taking LSD which may or may not have helped the creative juices to flow. By the end of the 1960s, Lennon was hooked on heroin and recorded one of his most infamous hits about its withdrawal symptoms (‘Cold Turkey’).

By the late 1960s, the Beatles (along with many of the big pop stars of the day) were also searching for other mind altering experiences and the ‘meaning of life’ which led them to the Maharishi Mahesh Yogi (‘Maharishi’ meaning ‘great seer’) and his teachings on transcendental meditation (TM). I myself dabbled in TM during the early 1990s, and over the last few years I have developed a new line of research on mindfulness meditation with my colleagues Edo Shonin and William Van Gordon (see ‘Further reading’). The Beatles (and George Harrison particularly) stimulated me to learn more about Buddhist philosophy. One of the Beatles most innovative songs ‘Tomorrow Never Knows’ – the final track on the 1966 Revolver album – was written by Lennon after reading The Psychedelic Experience: A Manual Based on The Tibetan Book of the Dead written by Timothy Leary, Ralph Metzner and Richard Alpert. However, it was Harrison who was most swayed and his spiritual beliefs rooted in Buddhism stayed with him until his dying day. Although I am not religious in the slightest, the lyrics to some of Harrison’s best songs while he was in The Beatles dealing with Buddhist philosophy are simply beautiful (‘Within You, Without You’ and ‘The Inner Light’ being the best examples; arguably you could add Lennon’s ‘Across The Universe’ to this list).

When I first started listening to The Beatles at the age of around 5 or 6 years of age, it was the music and the melodies that I loved (particularly the 1962-1965 period). By my late teens it was the later songs (1966-1969) and the more sophisticated musical layers that I loved (and still do). Now when I listen to their songs I am most interested in what the songs are trying to say and their philosophical or psychological underpinnings. Any analysis of their songs over time demonstrates that they went from a repertoire dominated by songs about love and relationships (‘Love Me Do’, ‘Please Please Me’, ‘From Me To You’, ‘She Loves You’, and ‘I Wanna Hold Your Hand’, ‘Eight Days A Week’) to a much wider range of topics many of which covered psychological topics such as childhood nostalgia (‘In My Life’, ‘Strawberry Fields Forever’, and ‘Penny Lane’), mind-wandering (‘Fixing A Hole’), domestic violence (‘Getting Better’), jealousy (‘Run For Your Life’, ‘You Can’t Do That’, ‘What Goes On’), casual sex/one-night stands (‘The Night Before’, ‘Day Tripper’), prostitution (‘Polythene Pam’, ‘Maggie Mae’), [alleged] drug use (‘Dr. Robert’, ‘A Day In The Life’, ‘Happiness Is A Warm Gun’, ‘What’s The New Mary Jane‘), running away from home (‘She’s Leaving Home’), homelessness (‘Mean Mr. Mustard’), insomnia (‘I’m So Tired’), depression due to relationship troubles (‘I’m Down’, ‘I’m A Loser’, ‘Help’, ‘Baby’s In Black’, ‘Yesterday’, ‘You’ve Got To Hide Your Love Away’, ‘Ticket To Ride’, ‘For No-One’), suicide (‘Yer Blues’), murder (‘Maxwell’s Silver Hammer’), and death (‘She Said She Said’, ‘Tomorrow Never Knows’).

There were also those songs that were overtly political (‘Taxman’, ‘Revolution’), self-referential (‘Glass Onion’), and autobiographical (‘The Ballad of John and Yoko’, ‘Julia’, ‘Dear Prudence’, ‘Norwegian Wood [This Bird Has Flown]) to songs that were rooted in surrealism (most notably ‘I Am The Walrus’, ‘Lucy In The Sky With Diamonds’, ‘What’s The New Mary Jane‘) and the experimental avant garde (‘Revolution 9’, ‘You Know My Name [Look Up The Number]‘, and – the yet to be released and holy grail for Beatles collectors – ‘Carnival of Light’).

In short, repeated listening to The Beatles’ output brings me continued pleasure. I feel good when I listen to the Beatles. I can listen to The Beatles and create playlists to reflect the mood I’m in. I can simply read the lyrics to their songs and look for meanings that probably weren’t intended by the songwriter. In short, I am constantly rewarded by listening to (and analysing the lyrics of) The Beatles. For me, listening to The Beatles is quite simply “group therapy”!

Dr. Mark Griffiths, Professor of Behavioural Addictions, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

The Beatles (1988). The Beatles Lyrics: The Songs of Lennon, McCartney, Harrison and Starr. London: Omnibus Press.

Davies, H. (2009). The Beatles: The Authorised Biography. London: Ebury.

Goldman, A. (1988). The Lives of John Lennon. W. Morrow.

Lewisohn, M. (1990). The Complete Beatles Chronicle. London: Harmony Books.

Janov, A. (1970). The Primal Scream. New York: Dell Books.

Janov A (1977). Towards a new consciousness. Journal of Psychosomatic Research, 21, 333–339.

Janov, A. (1980). Prisoners of Pain: Unlocking The Power Of The Mind To End Suffering. New York: Anchor Books.

Norman, P. (2011). Shout! the Beatles in their generation. New York: Simon and Schuster.

Sheff, D., & Golson, G. B. (1982). The Playboy Interviews with John Lennon and Yoko Ono. New York: Penguin Group.

Shonin, E., Van Gordon W., Compare, A., Zangeneh, M. & Griffiths M.D. (2015). Buddhist-derived loving-kindness and compassion meditation for the treatment of psychopathology: A systematic review. Mindfulness, 6, 1161–1180.

Shonin, E., Van Gordon W., & Griffiths, M.D. (2014). Current trends in mindfulness and mental health. International Journal of Mental Health and Addiction, 12, 113-115.

Shonin, E., Van Gordon W., & Griffiths M.D. (2014). The emerging role of Buddhism in clinical psychology: Towards effective integration. Psychology of Religion and Spirituality, 6, 123-137.

Shonin, E., Van Gordon, W. & Griffiths, M.D. (2015). Does mindfulness work? Reasonably convincing evidence in depression and anxiety. British Medical Journal, 351, h6919 doi: 10.1136/bmj.h6919.

Shonin, E., Van Gordon, W., & Griffiths, M.D. (2016). Mindfulness and Buddhist-derived Approaches in Mental Health and Addiction. New York: Springer.

Van Gordon, W., Shonin, E., & Griffiths, M.D. (2017). Buddhist emptiness theory: Implications for the self and psychology. Psychology of Religion and Spirituality, in press.

Van Gordon W., Shonin, E., Griffiths M.D. & Singh, N. (2015). There is only one mindfulness: Why science and Buddhism need to work together. Mindfulness, 6, 49-56.

Wenner, J. (2001). Lennon Remembers. Verso.

Wikipedia (2017). Arthur Janov. Located at: http://en.wikipedia.org/wiki/Arthur_Janov

Wikipedia (2017). Primal therapy. Located at: http://en.wikipedia.org/wiki/Primal_therapy

More cock tales: A brief look at genital drug injection

The idea for this blog was initiated when I read a snippet in The Fortean Times about a 34-year old man from New York who injected cocaine into his penis and ended up with gangrene and further medical complications. It turns out that this report was based on a letter published in a 1988 issue of the Journal of the American Medical Association by Drs. John Mahler, Samuel Perry and Bruce Sutton (and subsequently reported in a June 1988 issue of the New York Times).

The man in question came in for medical treatment following three days of priapism (i.e., prolonged and painful penile erection) and paraphimosis (i.e., foreskin in uncircumcised males can no longer be pulled over the tip of the penis). To enhance his sexual performance, he had administered cocaine directly into his urethra. After three days, both the priapism and the paraphimosis “spontaneously resolved”. However, the blood that had caused the priapism then leaked to other areas of his body over the next 12 hours (including his feet, hands, genitals, chest, and back). To stop the spread of gangrene, the medics had to partially amputate both of his legs (above the knee), and nine of his fingers. Following this, his penis also developed gangrene and fell off by itself while he was taking a bath. The exact reason for the spread of gangrene was unknown but sexologists (such as Professor John Money) speculated that it may have been because of impure cocaine being used.

When I started to search for medical literature on the topic of injecting drugs directly into male genitalia I was surprised to find quite a few papers on the topic (but unsurprisingly all case study reports given the rarity of such behaviour). One of the earliest I located was one from 1986 in the Journal of Urology by Dr. W. Somers and Dr. F. Lowe. They reported the cases of four heroin abusers with localized gangrene of the genitalia, although only one of these had actually injected heroin directly into his genitalia, in this case his scrotum and perineum (the area between the anus and the scrotum). This latter case developed more severe gangrene and was described as a “more lethal entity” than the gangrene in the other three heroin users’ genitalia.

Later, in a 1999 issue of the American Journal of Forensic Medicine and Pathology, Dr. Charles Winek and his colleagues reported the rare case of a fatality due to a male injecting heroin directly into his penis. The cause of death was determined to be due to heroin and ethanol intoxication. More recently, in a 2005 issue of the Medical Journal of the Iranian Red Crescent, Dr. Z. Ahmadinezhad and his colleagues reported a case of heroin-associated priapism. In their paper, they reported the case of a 32-year old man who was admitted to hospital following pain and swelling after injecting heroin into his penis two weeks earlier. Unfortunately, the person left the hospital following initial consultation and never came back so the outcome of the treatment provided is unknown.

In a 2011 issue of the Internet Journal of Surgery, Dr. I. Malek and colleagues reported the case of a 35-year old long-term intra-venous drug user who injected citric acid laced with heroin into the dorsal vein of his penis. This caused worsening pain and his penis developed gangrene. Over the (non-operative) treatment period, the man’s pain became worse and he had trouble urinating (so he was catheterised). Eventually, the treatment with antibiotics led to a good recovery at three-month follow-up.

Another unusual case was reported by Dr. Francois Brecheteau and his colleagues in a 2013 issue of the Journal of Sexual Medicine. They reported the successful treatment of a 26-year old male drug addict who had injected the opiate drug buprenorphine directly into the dorsal vein of his penis. After unsuccessful antibiotic treatment on its own, they then used a number of simultaneous treatments including heparin, anti-platelet drugs, antibiotics, and hyperbaric oxygen therapy, the man made a successful recovery.

Returning to cocaine rather than opiates, a case report by Dr. V. B. Mouraviev and his colleagues in a 2002 issue of the Scandinavian Journal of Urology and Nephrology reported the case of a 31-year-old Canadian man who had injected cocaine directly into his penis. He turned up at the emergency having endured penile pain for 22 hours following the injection. Twelve hours after injecting the cocaine, the man noticed swelling and bruising starting to appear on the right side of his penis where he had made the injection. As a consequence, his penis developed gangrene (“localized death and decomposition of body tissue, resulting from obstructed circulation or bacterial infection”) most probably from bacterial infection via the injection. He had to undergo reconstructive skin graft surgery and was given antibiotics. In this particular case, the treatment was successful. Other similar reports of medical complications (usually gangrene) following the injection of cocaine into the penis have since appeared in a number of papers including a 2013 paper by Dr. Fahd Khan and colleagues in the Journal of Sexual Medicine.

Cocaine and heroin aren’t the only recreational drugs to have been injected into male genitalia. A paper in a 2014 issue of Urology Case Reports by Dr. Cindy Garcia and her colleagues reported the case of a 45-year-old male intravenous drug user who developed an abscess after he injected amphetamine into his penis. The man chose a penile vein after being unable to find any other suitable peripheral vein. He was treated with intravenous antibiotics and had to have his abscess drained via a penile incision. Within a month he had been all but successfully treated. In their paper (which also included a review of the literature on penile abscesses), they concluded that:

“Penile abscesses are an uncommon condition. There are multiple aetiologies of penile abscesses, including penile injection, penile trauma, and disseminated infection. Penile abscesses might also occur in the absence of an underlying cause. The treatment of penile abscesses should depend on the extent of infection and the cause of the abscess. Most cases of penile abscess necessitate surgical debridement [removal of dead or infected tissue]”.

Similarly, in a 2015 issue of Case Reports in Urology, Dr. Thomas W. Gaither and his colleagues reported two cases of men who had injected metamphetamine into their penis. The first case was a 47-year-old gay man who had a history of “methamphetamine use, prior penile abscesses, urethral foreign body insertions, HIV, hepatitis C, and diabetes mellitus”. He attended the hospital emergency department suffering from severe penile pain and scrotal swelling having injected methamphetamine into the shaft of his penis a few days before. On the same day that he went to the emergency department he was immediately taken into the operating room where an incision was made in his penis, and the abscess was drained of its “purulent foul-smelling fluid” and washed out with saline solution. The second case was a 33-year-old heterosexual male with no previous medical history (apart from a history of depression) turned up at the hospital emergency department with acute penile pain, a day after he had injected methamphetamine directly into his penis. Again, he was immediately taken to the operating room where his penile abscess was drained after an incision. Neither of the cases involved any penile gangrene and both men were also given antibiotics to treat the infected area. In both cases, the authors speculated that the abscesses formed as a result of direct contamination from repeated penile injections.

Finally, Dr. Lucas Prado and his colleagues reported a case study in a 2012 issue of the Journal of Andrology of a 31-year-old man who was admitted to the emergency department after he had injected 10ml of methadone into his penis in an attempt to commit suicide (the first case of penile methadone injection). The man had a 15-year history of drug abuse over the past year and had attempted a drug-related suicide three times. This particular suicide attempt led to acute liver and renal failure as well as erectile dysfunction. Although the man survived, ten months after the suicide attempt, the man still had complete erectile dysfunction.

Although I didn’t do a systematic review of all the literature, it is clear that the injection of recreational drugs directly into male genitalia appears to be relatively rare although all the literature I located was based on those who end up seeking treatment for when things go horribly wrong. There could of course be many hundreds or thousands of people out there that have engaged in such practices but don’t end up in a hospital emergency ward. However, I certainly wouldn’t recommend such a practice to anyone.

Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Ahmadinezhad, Z., Jabbari, B.H., Saberi, H., Khaledi, F., & Safavi, F. (2005). Heroin associated priapism. Medical Journal of the Iranian Red Crescent, 7(3), 67-68.

Brecheteau, F., Grison, P., Abraham, P., Lebdai, S., Kemgang, S., Souday, V., … & Bigot, P. (2013). Successful medical treatment of glans ischemia after voluntary buprenorphine injection. Journal of Sexual Medicine, 10(11), 2866-2870.

Cunningham, D.L., & Persky, L. (1989). Penile ecthyma gangrenosum: Complication of drug addiction. Urology, 34(2), 109-110.

Gaither, T.W., Osterberg, E.C., Awad, M. A., & Breyer, B.N. (2015). Surgical intervention for penile methamphetamine injections. Case Reports in Urology, 467683, doi.org/10.1155/2015/467683

Garcia, C., Winter, M., Chalasani, V., & Dean, T. (2014). Penile abscess: a case report and review of literature. Urology Case Reports, 2(1), 17-19.

Khan, F., Mukhtar, S., Anjum, F., Tripathi, B., Sriprasad, S., Dickinson, I. K., & Madaan, S. (2013). Fournier’s gangrene associated with intradermal injection of cocaine. Journal of Sexual Medicine, 10(4), 1184-1186.

Malek, I., Parmar, C., McCabe, J., & Irwin, P. (2011). Successful non-operative management of penile wet gangrene following self-injection of heroin in dorsal vein of penis. Internet Journal of Surgery, 11(1), 1-3.

Mireku-Boateng, A.O., & Tasie, B. (2001). Priapism associated with intracavernosal injection of cocaine. Urologia Internationalis, 67(1), 109-110.

Mouraviev, V. B., Pautler, S. E., & Hayman, W. P. (2002). Fournier’s gangrene following penile self-injection with cocaine. Scandinavian Journal of Urology and Nephrology, 36(4), 317-318.

Munarriz, R., Hwang, J., Goldstein, I., Traish, A.M., & Kim, N.N. (2003). Cocaine and ephedrine-induced priapism: case reports and investigation of potential adrenergic mechanisms. Urology, 62(1), 187-192.

Prado, L. G., Huber, J., Huber, C. G., Mogler, C., Ehrenheim, J., Nyarangi‐Dix, J., … & Hohenfellner, M. (2012). Penile methadone injection in suicidal intent: Life‐threatening and fatal for erectile function. Journal of Andrology, 33(5), 801-804.

Singh, V., Sinha, R. J., & Sankhwar, S. N. (2011). Penile gangrene: A devastating and lethal entity. Saudi Journal of Kidney Diseases and Transplantation, 22(2), 359.

Somers, W.J., & Lowe, F.C. (1986). Localized gangrene of the scrotum and penis: A complication of heroin injection into the femoral vessels. Journal of Urology, 136, 111-113.

Winek, C. L., Wahba, W. W., & Rozin, L. (1999). Heroin fatality due to penile injection. American Journal of Forensic Medicine and Pathology, 20(1), 90-92.

Higher and higher: Can psychoactive substance use enhance creativity?

In a previous blog I examined whether celebrities are more prone to addictions. In that article I argued that many high profile celebrities have the financial means to afford a drug habit like cocaine or heroin. For many in the entertainment business such as being the lead singer in a famous rock band, taking drugs may also be viewed as one of the defining behaviours of the stereotypical ‘rock ‘n’ roll’ lifestyle. In short, it’s almost expected. There is also another way of looking at the relationship between celebrities and drugs and this is in relation to creativity, particularly as to whether the use of drugs can inspire creative writing or music. For instance, did drugs like cannabis and LSD help The Beatles create some of the best music ever such as Revolver? Did the Beach Boys’ Brian Wilson’s use of drugs play a major role in why the album Pet Sounds is often voted the best album of all time? Did the use of opium by Edgar Allen Poe create great fiction? Did William S. Burroughs’ use of heroin enhance his novel writing?

To investigate the question of whether drug use enhances creativity, I and my research colleagues Fruzsina Iszáj and Zsolt Demetrovics have just published a review paper in the International Journal of Mental Health and Addiction examining this issue. We carried out a systematic review of the psychological literature and reviewed any study that provided empirical data on the relationship between psychoactive substance use and creativity/artistic creative process that had been published in English in peer-reviewed journals or scientific books. Following a rigorous filtering process, we were surprised to find only 19 studies that had empirically examined the relationship between drug use and creativity (14 empirical studies and five case studies).

Six of the 19 studies (four empirical papers and two case reports) were published during the 1960s and 1970s. However, following the peak of psychedelia, only three papers (all of them empirical) were published in the following 20 years. Since 2003, a further 10 studies were published (seven empirical papers and three case studies). The majority of the studies (58%) were published in the USA. This dominance is especially true for the early studies in which six of the seven empirical papers and both case studies that were published before mid-1990s were written by US researchers. However, over the past 14 years, this has changed. The seven empirical papers published post-2000 were shared between six different countries (USA, UK, Italy, Wales, Hungary, Austria), and the three case studies came from three countries (USA, UK, Germany).

Seven empirical papers and two case studies dealt with the relationship between various psychoactive substances and artistic creation/creativity. Among the studies that examined a specific substance, six (three empirical papers and three case studies) focused on the effects of either LSD or psilocybin. One empirical study focused on cannabis, and one concerned ayahuasca.

With the exception of one study where the sample focused on adolescents, all the studies comprised adults. More non-clinical samples (15 studies, including case studies) were found than clinical ones (four studies). Three different methodological approaches were identified. Among the empirical studies, seven used questionnaires comprising psychological assessment measures such as the Torrance Test of Creative Thinking (TTCT).

According to the types of psychoactive substance effect on creativity, we identified three groups. These were studies that examined the effect of psychedelic substances (n=5), the effect of cannabis (n=1), and those that did not make a distinction between substances used because of the diverse substances used by participants in the samples (n=7). In one study, the substances studied were not explicitly identified.

The most notable observation of our review was that the findings of these studies show only limited convergence. The main reason for this is likely to be found in the extreme heterogeneity concerning the objectives, methodology, samples, applied measures, and psychoactive substances examined among the small number of studies. Consequently, it is hard to draw a clear conclusion about the effect of psychoactive substance use on creativity based on the reviewed material.

Despite the limited agreement, most of the studies confirmed some sort of association between creativity and psychoactive substance use, but the nature of this relationship was not clearly established. The frequently discussed view that the use of psychoactive substances leads to enhanced creativity was by no means confirmed. What the review of relevant studies suggests is that: (i) substance use is more characteristic in those with higher creativity than in other populations, and (ii) it is probable that this association is based on the inter-relationship of these two phenomena. At the same time, it is probable that there is no evidence of a direct contribution of psychoactive substances to enhanced creativity of artists.

It is more likely that substances act indirectly by enhancing experiences and sensitivity, and loosening conscious processes that might have an influence on the creative process. This means the artist will not be more creative but the quality of the artistic product will be altered due to substance use. On the other hand, it appears that psychoactive substances may have another role concerning artists, namely that they stabilize and/or compensate a more unstable functioning.

Beyond the artistic product, we also noted that (iii) specific functions associated with creativity appear to be modified and enhanced in the case of ordinary individuals due to psychoactive substance use. However, it needs to be emphasized that these studies examined specific functions while creativity is a complex process. In light of these studies, it is clear that psychoactive substances might contribute to a change of aesthetic experience, or enhanced creative problem solving. One study (a case study of the cartoonist Robert Crumb) showed that LSD changed his cartoon illustrating style. Similarly, a case study of Brian Wilson argued that the modification of musical style was connected to substance use. However, these changes in themselves will not result in creative production (although they may contribute to the change of production style or to the modification of certain aspects of pieces of arts). What was also shown is that (iv) in certain cases, substances may strengthen already existing personality traits.

In connection with the findings reviewed, one should not overlook that studies focused on two basically different areas of creative processes. Some studies examined the actual effects of a psychoactive substance or substances in a controlled setting, while others examined the association between creativity and chronic substance users. These two facets differ fundamentally. While the former might explain the acute changes in specific functions, the latter may highlight the role of chronic substance use and artistic production.

It should also be noted that the studies we reviewed differed not only regarding their objectives and methodology, but also showed great heterogeneity in quality. Basic methodological problems were identified in many of these studies (small sample sizes, unrepresentative samples, reliance on self-report and/or non-standardized assessment methods, speculative research questions, etc.). Furthermore, the total number of empirical studies was very few. At the same time, the topic is highly relevant both in order to understand the high level of substance use in artists and in order to clarify the validity of the association present in public opinion. However, it is important that future studies put specific emphasis on adequate methodology and clear research questions.

Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Belli, S. (2009). A psychobiographical analysis of Brian Douglas Wilson: Creativity, drugs, and models of schizophrenic and affective disorders. Personality and Individual Differences, 46, 809-819.

Dobkin de Rios, M. & Janiger, O. (2003). LSD, spirituality, and the creative process. Rochester, VT: Park Street Press.

Edwards, J. (1993). Creative abilities of adolescent substance abusers. Journal of Group         Psychotherapy, Psychodrama & Sociometry, 46, 52-60.

Fink, A., Slamar-Halbedl, M., Unterrainer, H.F. & Weiss, E.M. (2012). Creativity: Genius, madness, or a combination of both? Psychology of Aesthetics, Creativity, and the Arts, 6(1), 11–18.

Forgeard, M.J.C. & Elstein, J.G. (2014). Advancing the clinical science of creativity. Frontiers in Psychology, 5, 613.

Frecska, E., Móré Cs. E., Vargha, A. & Luna, L.E. (2012). Enhancement of creative expression and entoptic phenomena as after-effects of repeated ayahuasca ceremonies. Journal of Psychoactive Drugs, 44, 191-199

Holm-Hadulla, R.M. & Bertolino, A. (2014). Creativity, alcohol and drug abuse: The pop icon Jim Morrison. Psychopathology, 47,167-73

Iszáj, F. & Demetrovics, Z. (2011). Balancing between sensitization and repression: The role of opium in the life and art of Edgar Allan Poe and Samuel Taylor Coleridge. Substance Use and Misuse, 46, 1613-1618

Iszaj, F., Griffiths, M.D. & Demetrovics, Z. (2016). Creativity and psychoactive substance use: A systematic review. International Journal of Mental Health and Addiction. doi: 10.1007/s11469-016-9709-8

Jones, M.T. (2007). The creativity of crumb: Research on the effects of psychedelic drugs on the comic art of Robert Crumb. Journal of Psychoactive Drugs, 39, 283-291.

Jones, K.A., Blagrove, M. & Parrott, A.C. (2009). Cannabis and ecstasy/ MDMA: Empirical measures of creativity in recreational users. Journal of Psychoactive Drugs. 41(4), 323-329

Kerr, B. & Shaffer, J. & Chambers, C., & Hallowell, K. (1991). Substance use of creatively talented adults. Journal of Creative Behavior, 25(2), 145-153.

Knafo, D. (2008). The senses grow skilled in their craving: Thoughts on creativity and addiction. Psychoanalytic Review, 95, 571-595.

Lowe, G. (1995). Judgements of substance use and creativity in ’ordinary’ people’s everyday lifestyles. Psychological Reports. 76, 1147-1154.

Oleynick, V.C., Thrash, T. M., LeFew, M. C., Moldovan, E. G. & Kieffaber, P. D. (2014). The scientific study of inspiration in the creative process: challenges and opportunities. Frontiers in Human Neuroscience, 8, 436.

Plucker, J.A., McNeely, A. & Morgan, C. (2009). Controlled substance-related beliefs and use: Relationships to undergraduates’ creative personality traits. Journal of Creative Behavior, 43(2), 94-101

Preti, A. & Vellante, M. (2007). Creativity and psychopathology. Higher rates of psychosis proneness and nonright-handedness among creative artists compared to same age and gender peers. Journal of Nervous and Mental Disease, 195(10), 837-845.

Schafer, G. & Feilding, A. & Morgan, C. J. A. & Agathangelou, M. & Freeman, T. P. &      Curran, H.V. (2012). Investigating the interaction between schizotypy, divergent thinking and cannabis use. Consciousness and Cognition, 21, 292–298

Thrash, T.M., Maruskin, L.A., Cassidy, S. E., Fryer, J.W. & Ryan, R.M. (2010). Mediating between the muse and the masses: inspiration and the actualization of creative ideas. Journal of Personality and Social Psychology, 98, 469–487.

What a drag: A brief look at cigarette smoking and nicotine dependence

Cigarette smoking among adults (i.e., those aged 18 years and over) has been a highly prevalent behaviour in Great Britain for decades but overall rates have significantly declined in recent times. Figures show that the highest recorded level of nicotine smoking among British males was in 1948 when four-fifths smoked (82%) although at that time only two-thirds smoked manufactured cigarettes (as the rest smoked pipes and/or cigars). The highest recorded level of nicotine smoking among British females was in the mid-1960s (45%) slightly higher than the prevalence rate of 41% in 1948.

A 2003 study by Dr. M. Jarvis in the journal Addiction reported that since 2000 the overall adult smoking rates in Great Britain had been declining by around 0.4% per year. More recently, the British prevalence rates of smoking remained constant at 21% between 2007 and 2009 (according to a 2013 report by Action on Smoking and Health [ASH]). According to the 2013 Office for National Statistics report, the most recent prevalence rate is 20% (21% of men and 19% of women). This equates to around 10 million British adult cigarette smokers. Smoking prevalence rates are highest in young adults. More specifically, in the 20-24 year age group, the prevalence rate of nicotine smoking is 30% in males and 28% in females. Only 1% of children are nicotine smokers at the age of 11 years. By the age of 15 years, 11% of children are regular smokers. As the 2013 ASH report noted:

“Since the mid 1970s cigarette consumption has fallen among both men and women. The overall reported number of cigarettes smoked per male and female smoker has changed little since the mid 1980s, averaging 13 cigarettes per smoker per day. As in previous years, men smoked slightly more per day on average than women and there was an association between consumption and socio-economic group. In 2011, smokers in manual occupations smoked an average of 14 cigarettes a day compared with 11 a day for those in managerial or professional groups… In 2011, 63% of smokers said they would like to stop smoking altogether. Other ways of measuring dependence include how difficult people would find it to go for a whole day without smoking and how soon they smoke after waking… In 2011, 60% of smokers said they would find it hard to go for a whole day without smoking. Eighty-one per cent of heavier smokers (20 or more a day) said they would find it difficult, compared to 32% of those smoking fewer than 10 cigarettes per day”.

Like drug addictions more generally, nicotine addiction is a complex combination of influences including genetic, pharmacological, psychological, social and environmental factors. In 2010, the US Surgeon General asserted that “there is no established consensus on criteria for diagnosing nicotine addiction” but that there are a number of symptoms can be viewed as addiction indicators such as:

• Drug use that is highly controlled or compulsive with psychoactive effects
• Stereotypical patterns of use
• Continued use despite harmful effects
• Relapse following abstinence accompanied by recurrent cravings.

A 2000 report by the Royal College of Physicians also noted that nicotine fulfils criteria for defining an addiction and states that:

“It is reasonable to conclude that nicotine delivered through tobacco smoke should be regarded as an addictive drug, and tobacco use as the means of self-administration…Cigarettes are highly efficient nicotine delivery devices and are as addictive as drugs such as heroin or cocaine.”

One of the key characteristics of drug addiction or dependence on a substance is the degree of compulsion experienced by the user. Since 1992, the British General Lifestyle Survey (which typically surveys around 15,000 adults from over 9000 households annually) has asked three questions relevant to nicotine dependence and addiction. The first is whether the person would like to stop smoking, the second is whether person would find it easy or difficult not to smoke for a whole day, and the third is how soon after waking up they smoke their first cigarette. Since 1992, there has been almost no change in any of the three measures.

The latest 2013 survey reported that 63% of smokers said they would like to stop smoking altogether and 60% felt it would be difficult for them to go a day without smoking. Four-fifths (81%) of heavy smokers (i.e., those smoking 20 or more cigarettes a day) said they would find it difficult to give up smoking compared to one-third (32%) of lighter smokers (i.e., those smoking less than 10 cigarettes a day). The average number of cigarettes smoked per day is 13, and 14% smoke a cigarette within five minutes of getting up in the morning, a figure that rises to 35% among heavy smokers who smoke more than 20 cigarettes a day. Research consistently shows that approximately two-thirds of smokers want to quit the behaviour yet the majority are unable to do so, which is also suggestive of a genuine addiction. Those that do try to quit smoking typically experience a wide range of withdrawal symptoms including craving for nicotine, irritability, anxiety, difficulty concentrating, restlessness, sleep disturbances, decreased heart rate, and increased appetite or weight gain.

Outside of Great Britain, tobacco and other drug use prevalence have been examined extensively among youth and adults. For example, by the Monitoring the Future research group in the U.S. (http://monitoringthefuture.org). They reported that daily (20 or more days in last 30 days) cigarette smoking varied from 11.4% among 18 year olds to 17% among 50 year olds. One may infer that daily cigarette smoking is addictive use, though several studies measure tobacco (nicotine) addiction specifically. Tobacco addiction (dependence) among older teenagers has been found to vary between 6% and 8%. Studies have found a prevalence rates of between 1.7% to 9.6% for tobacco addiction among college students.

In a 2004 issue of the Archives of General Psychiatry, Dr. Jon Grant and colleagues found a prevalence of 12.8% for tobacco addiction among a U.S. national sample of adults. A few years later in a 2009 issue of the American Journal of Public Health, Dr. R.D. Goodwin and colleagues found a prevalence of 21.6% and 17.8% for tobacco addiction among a U.S. national sample of male and female adults, respectively. It appears that daily smoking demonstrates about the same level of prevalence as direct measures of dependence, particularly among adults.

In a 2011 study that I carried out with Dr. Steve Sussman and Nadra Lisha, we estimated that past year nicotine dependence prevalence in the general adult population of the U.S. as being approximately 15%. A different summary of research on the epidemiology of drug dependence has shown that of all people who initiate cigarette use, almost one-third become addicted smokers (32%), a figure that is much higher addiction rate than for users of heroin (23%), cocaine (17%), alcohol (15%) or cannabis (9%).

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Action on Smoking and Health (2012). Nicotine and addiction. London: Action on Smoking and Health.

Action on Smoking and Health (2013). Smoking statistics: Who smokes and how much. London: Action on Smoking and Health.

Benowitz, N. (2010). Nicotine addiction. New England Journal of Medicine, 362, 2295–2303,

Carpenter C.M., Wayne, G.F., & Connolly, G.N. (2007). The role of sensory perception in the development and targeting of tobacco products. Addiction, 102, 136-147.

Goodwin, R.D., Keyes, K.M., & Hasin, D.S. (2009). Changes in cigarette use and nicotine dependence in the United States: Evidence from the 2001-2002 wave of the National Epidemiologic Survey of Alcoholism and Related Conditions. American Journal of Public Health, 99, 1471-1477.

Grant, B.F., Hasin, D.S., Chou, P., Stinson, F.S., & Dawson, D.A. (2004a). Nicotine dependence and psychiatric disorders in the United States. Archives of General Psychiatry, 61, 1107-1115.

Information Centre for Health and Social Care (2011). Smoking drinking and drug use among young people in England in 2011. London: Information Centre for Health and Social Care.

Jarvis, M. (2003). Monitoring cigarette smoking prevalence in Britain in a timely fashion. Addiction, 98, 1569-1574.

Office for National Statistics (2012). The 2010 General Lifestyle Survey. London: Office for National Statistics.

Office for National Statistics (2013). The 2011 General Lifestyle Survey. London: Office for National Statistics.

Sussman, S., Lisha, N. & Griffiths, M.D. (2011). Prevalence of the addictions: A problem of the majority or the minority? Evaluation and the Health Professions, 34, 3-56.

Wald, N. & Nicolaides-Bouman, A. (1991). UK Smoking Statistics (2nd edition). Oxford: Oxford University Press.