Category Archives: Gender differences
In previous blogs I have examined a number of extreme behaviours involving hands (both sexual and non-sexual) including hand wear fetishism, fingernail fetishism, ‘hands on hip’ fetishism, alien hand syndrome, ‘touch the truck’ endurance television, and thumb sucking as an addiction. However, it was while I was researching a previous blog on belly inflation fetishes that I came across a man who on the Yahoo! Answers website claimed he had a belly inflation fetish and a thumb fetish along with another person who responded saying he also shared the same fetish:
- Extract 1: “Another weird fetish I have is ‘hitchhiker’s thumb’. Hitchhikers thumb is when the top part of your thumb bends backwards when pushed on or fully extended…The hitchhiker’s thumb fetish developed when I found out that my cousins could do it. I would ALWAYS ask questions about it and I would bend her thumbs back and forth for hours. And I just get turned on by it now…is this weird?” (Male, sexual orientation unknown)
- Extract 2: “I [also] have a fetish for bendy thumbs hence the profile pic. It’s all good I say whatever turns u on and if not hurting anyone then it’s cool” (Male, sexual orientation unknown)
Although I have read about (i) thumb bondage (mentioned in a 2007 book chapter on themes of sadomasochistic expression by Dr. Charles Moser and Dr. Peggy Kleinplatz) and (ii) thumb sucking by adult babies that are into paraphilic infantilism, I had never read anything on standalone thumb fetishes. (I would also point out that the ‘thumb sucking’ is just one of many baby-like behaviours that paraphilic infantilists enjoy but do not necessarily see as a source of arousal in and of itself). There is also those who say that they engage is ‘thumb sex’ and defined by the online Urban Dictionary as “when two people hold hands and run their thumbs around the other persons thumb or twiddle the thumbs”. There are also (for want of a better word) ‘cultural’ references to thumb fetishes such as the instrumental song ‘Mayor Oscar Goodman’s Thumb Fetish’ by US deathcore band Molotov Solution.
As far as I am aware there has never been any empirical research on thumb fetishism. There are various online websites and forums that feature individuals that claim to have very specific types of thumb fetishes. This is one of the more specific that I found:
- Extract 3: “I’m a 34 year old men and I have thin thumbs (each ones have the same width as an American/Canadian penny, that’s 0.74 inch or 19 millimeters). I got a fetish that seems to be pretty rare. It consists of being turn on by comparing my thin thumbs with a woman that has larger ones than mine. Also, the younger the woman is with larger thumbs, the better. It’s pretty inoffensive, but rare I think” (Male heterosexual).
There are also whole webpages dedicated to the sexiness of thumb sucking. Here are some of the online accounts I found on the Thumb Sucking Adults website. They begin by noting that adult thumb sucking is “sexy. This fact shouldn’t be too surprising in that it involves the sensual oral center [and] so much of what is human has become sexualized in one way or another that thumb sucking adults is just another part of the total picture”. They then highlight some of their readers’ experiences:
- Extract 3: “I am a bisexual woman who finds other women sucking their thumbs extremely erotic…First of all, growing up, I had a very close friend who lived down the street from me who also sucked her thumb. Experimenting with sex at a very early age…[she] and I would spend hours together exploring our bodies and touching each other. We learned how to masturbate and although I was so young, I discovered how to reach orgasm. I think perhaps Janice and I shared a certain closeness in our friendship and later in our intimacy because we both sucked our thumbs and felt accepted by each other if not by peers who seemed to ridicule us…I can summarize that my earliest, deepest feelings of sexual desire were connected to both thumb sucking and a female partner. Many years passed and I dated men here and there, but never quite felt emotionally or sexually fulfilled [as with women]…From the e-mails I’ve read on your site, I have also noticed that it is mostly the men who find thumbsucking erotic. Perhaps as a woman who is mostly gay and possesses some traits and attributes more commonly associated with men…I am more turned on by this than other women. And why does it turn me on? I’m sure it has to do with my childhood friend and the feelings associated with that particular behavior”(Bisexual female).
- Extract 4: “The arousal that naturally occurs when I do it. Thumb in mouth…hand on penis. This goes way back. I had contributed an early ‘embarrassment’ to [another website] saying that I watched a home movie in front of all our relatives and there was this shot of me, around 3 years old, standing by the garage, thumb in mouth, hand holding crotch. I had never seen that before. There was devilish laughter. I laughed along, but was shocked. I do remember a dry climax sucking my thumb when I was about 6 or 7. And my first real emission at age 12 or 13 involved thumb sucking in my bed. So it is very ingrained in me. The physical feeling of doing it brings such erotic pleasure. When I first insert my thumb in my mouth, pressing it against my palate and rubbing it back and forth about 1/2″, the stimulus begins. I don’t suck continuously. I do it for 1-2 minutes and take my thumb out for about 20 seconds and then put it back in. Each time it gets better and better. The key thing is that my thumb gets wetter and softer and SMOOTHER against my palate. I am very curious if anyone else sucks their thumb this way. I don’t actually SUCK it. I rub it. The other important part is that as I rub it, my tongue proceeds to pulsate. It’s involuntary. There’s no stopping it as long as I connect with the right spot on my palate. This enhances the feeling greatly. This dual rubbing, pulsating action. My thumb would have to be cut off to stop me from doing it. The last part of sexuality in thumb sucking is observing others doing it. I have to be honest in saying that watching…is an immense turn-on. Fortunately, I know I can control my desires” (Heterosexual male)
- Extract 5: “Larry finds many things attractive in a woman. One of these things, apparently, is that she sucks her thumb. It probably is not essential that she does so (if it was, we’d be talking more along the lines of a fetish) but, if she does suck her thumb, he finds that attractive, whatever the underlying psychodynamics. I propose that his preferences aren’t much different than, say, another man’s predilections for big-breasted women, though both allures aren’t necessarily exclusive…There are societal stigmas associated with the habit. Try sucking your thumb whenever you want to and you’ll see that at least an undue amount of attention will be focused your way for a while. The point is, perhaps as adult thumb sucking becomes more widely known, it is natural that some out there will find it an endearing quality in a person…For the adult thumb sucker, this site has been liberating…And, in the case of Larry, the fact that he has felt solitude in his thumb sucking, all his adult life, it’s certainly understandable to me that among all the feelings that are engendered when he sees it in another for the first time…[This website] simply proposes that adult thumb sucking is more common than otherwise assumed and should be accepted since it is, essentially, harmless and, for those that indulge, beneficial. As for thumb sucking being sexually provocative, I suppose that anything human can be sexualized by others eventually. As long as it’s legal, what’s wrong with that?” (Gender and sexual orientation unknown)
- Extract 6: “I love adult women who still suck on their thumb. Since I was a kid, I felt an attraction for girls sucking their thumbs. My twin sister sucked her thumb till she was 16 years old! When I first started masturbating at age 12, I thought of a girl sucking her thumb. I’ve always looked for women that sucked their thumb and then ask them to suck it for me. When I was 18, I met a girl I suspected of still sucking her thumb. Strangely, I noticed she didn’t have any marks or callus on her thumb. But from time to time, I saw teeth marks and lipstick marks on her thumb…We started to have thumb sucking sex and I loved it. She liked it also. We stayed together four years. It became a habit. She’d suck her thumb for me and then I’d suck her thumb while we made love. I never sucked my thumb but now I suck my thumb while masturbating and thinking about my former girlfriend’s thumb or another girl’s thumb. I always look for women sucking their thumbs in their cars while driving. I have seen three in all the years I have looked. Those times were awesome. I never tried to make contact. I am married now, but my wife never sucks her thumb. She will do it if I ask her, but that isn’t the same. I like it when an adult woman does it naturally…I love a woman with a thumb callus and nice teeth (there are a few). I love to see a wet thumb. I like it when an adult sucks her thumb with the index finger over the nose. I find that very sexy” (Heterosexual male).
- Extract 7: “I find thumb sucking sensual, sexual, erotic, comforting, calming…It’s like catching someone at their most vulnerable. Partly because of its social taboo, it can even be slightly ‘naughty’…But it is an exciting thought to me to perhaps one day ‘catch’ someone else thumb sucking. Thumb sucking provides sensations around the mouth and nose that can be reproduced during sex or loveplay, although thumb sucking is less tiring. It feels nice, smells nice, tickles [the] pleasure centers. It provides the sensations of skin-to-skin warmth that I think everyone of us craves…It’s sensual, it’s intimate. But it’s also sensual and sexual. I find myself sucking my thumb after sex much like I might grab for a cigarette…But I think that thumb sucking is by far more satisfying and truly far less addicting [than smoking]. And definitely far less damaging…Quite honestly I didn’t find out how much I found finger and thumb sucking an exciting part of foreplay and sex until I was 23” (Heterosexual female).
- Extract 8: “I suck my thumb for the usual reasons, tension relief, to go to sleep, it feels good. But, I notice that other contributors here suck their thumb because it also feels erotic, and, I have to say, I agree…When I’m aroused, it enhances the feeling so much more. So it’s obvious that I’ve learned to associate my thumb sucking with something sexual…When I look at the photos of women at this site, sucking away, I just find them so beautiful, so sexually enthralling….First off, there’s the lips. I think most people can understand why lips can be very erotic. I don’t want to get into heavy psychology, but, let’s face it, lips are sexy, especially full lips, parted ever so slightly. They’re like an invitation to something exciting…When I see a woman’s full lips open just a bit, my tongue gets an irresistible urge to explore her sweet mouth…If her teeth were affected by thumb sucking, all the better. The thought that she can’t stop her habit, and the pleasure she derives from it, even if her teeth are affected to the point of obvious buckedness adds that much more to my sensation…She looks like something innocent, childlike but not a child. Her profile, exaggerating her now protrusive lips, wrapped around a phallus-like object that is her compulsion, her requirement, her urgency…I want her thumb to feel comfortable in my mouth as I experience, once again, her essence, her habit as mine” (Heterosexual male).
Obviously this is just a small selection of online accounts of sexual thumb sucking I have come across and I can’t know for sure that they are genuine (but they appear that way to me). Also, I have no idea whether these are typical but I can make a few tentative conclusions. Firstly, both males and females can find thumb sucking sexually stimulating. Secondly, sexual thumb suckers tend to be heterosexual (although one account was from a bisexual woman). Thirdly, most experiences of sexual thumb sucking are rooted in childhood experiences and that the acquisition and development of such behaviour is related with associative pairing (i.e., classical conditioning). Fourthly, no-one pathologizes the behaviour, and as long as the act is consensual, there is absolutely nothing wrong with the behaviour as a sexual preference. Finally, none of the accounts suggest the sexual thumb sucking is fetishistic – just that it is a non-normative sexual expression that fits alongside their other sexual experiences.
While researching this article I also came across the remarkable story of American Rafe Briggs (from Oakland, California) in a 2013 issue of the International Business Times. In 2004, Biggs fell off a roof and broke his neck leaving him paralyzed from the chest down. He obviously thought he would never experience any kind of sexual pleasure again but he was wrong:
“Turns out he can. Biggs, 43, says that his thumb is his ‘surrogate penis’, and that he gets ‘orgasmic sensations’ whenever it’s stimulated. ‘I never thought it would be possible, but massaging and sucking on my thumb, feels a lot like my penis used to feel – it’s really hot” said Biggs, whose girlfriend helped him discover this phenomenon a year after the accident. Sex therapists like Lisa Skye Carle, who works with Biggs, calls it a ‘transfer orgasm – where another place on the body gives the same sensation”. Biggs has made it his mission to helping quadriplegics lead sexually fulfilling lives, working with the group ‘Sexability’ an ‘organization committed to empowering people with disabilities to explore sexuality and creating intimate loving relationships. Since our beginning in 2006, we have been working with individuals, groups and organizations to transform sexuality and disability’. ”
Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK
Huffington Post (2013). Rafe Biggs’ thumb has become his ‘surrogate penis’ after accident left him paralyzed, April 22, Located at: http://www.huffingtonpost.com/2013/04/22/rafe-biggs-thumb_n_3132325.html?utm_hp_ref=weird-news
Moser, C., & Kleinplatz, P. J. (2007). Themes of SM expression. In D. Langdridge & M. Barker (Eds.) Safe, sane & consensual: Contemporary perspectives on sadomasochism. (pp. 35-54). Hampshire, UK: Palgrave Macmillan.
Thumb Sucking Adults (undated). Why [thumb sucking] is sexy. Located at: http://www.thumbsuckingadults.com/mytsingissexypage.htm
Tungol, J.R. (2013). Paralyzed man Rafe Biggs has ‘orgasmic sensations’ through his thumb, ‘surrogate penis’ International Business Times. April 22. Located at: http://www.ibtimes.com/paralyzed-man-rafe-biggs-has-orgasmic-sensations-through-his-thumb-surrogate-penis-1208099
Most people now accept that weather can affect mood state and for some people can lead to extreme depression in the form of Seasonal Affective Disorder. There also seems to be some evidence that weather can affect people’s sex lives. Being too hot or too cold is likely to lessen the desire to engage in sexual behaviour. Most academic research appears to indicate that sex drives are higher in spring and summer. One of the reasons given for this is that during spring and summer, there is more sun, and that a particular hormone – Melanocyte Stimulating Hormone (MSH) – stimulates sex, particularly in women.
A number of studies have also indicated that during the spring and summer months, the body produces more seretonin (the so-called ‘feel good neurotransmitter’) because increased luminosity of sunlight. During the winter months as the amount of sunlight decreases, the body produces more melatonin, and this appears to inhibit sex drives. However, there is wide individual variation and the weather and subsequent hormone stimulation differs highly from one person to the next. As an online article by Shiv Joshi confirms:
“Sunlight has a direct effect on the brain’s serotonin production, according to researchers at the Human Neurotransmitter Laboratory and Alfred and Baker Medical Unit, Baker Heart Research Institute, Australia. Our serotonin levels increase with increase in luminosity. And how does that matter? Among other things, serotonin also regulates arousal, says Ray Sahelian, MD, author of Mind Boosters…Not just serotonin, but sunlight affects many other hormones in our body as well, some of which are associated with mood and pleasure feelings, according to professor Carmen Fusco, an instructor in pharmacology. It decreases melatonin, norepinephrine, and acetylcholine and increases cortisol, serotonin, GABA, and dopamine. The summer heat is good for your sex life too. It works on your muscles, by relaxing them and intensifies sensations of the skin. Further, the heat slows us down. This helps us get in touch with our more subdued sensual side, according to psychologist Stella Resnick, PhD, author of The Pleasure Zone”.
German researchers Winfried März and colleagues examined the relationship between vitamin D production (aided by sunny weather) and sex hormones (published a 2010 issue of the journal Clinical Endocrinology). In a study of 2,299 men, the researchers found that levels of Vitamin D were associated with androgen (i.e., testosterone) production with peak levels in August (the sunniest time of year in Germany). They concluded that testosterone and Vitamin D levels “are associated in men and reveal a concordant seasonal variation. Randomized controlled trials are warranted to evaluate the effect of vitamin D supplementation on androgen levels”. The study was replicated by Dr. Katharina Nimptsch and her colleagues among a sample of 1,362 men (also published in the same journal in 2012), and they found the same association between Vitamin D and testosterone production (although they found no seasonal effect). However, a more recent 2014 study published by Dr. Elizabeth Lerchbaim and her colleagues in the journal Andrology found no association (but it was on a much smaller sample of 225 men).
Although I have been unable to track down the academic source, an article by Sam Rider in Coach Magazine claimed that:
“Exposing the skin to sunlight for just 15-20 minutes can raise your testosterone levels by 120%, says a report from Boston State Hospital in the US. The research also found that the hormone increased by a whopping 200% when genital skin was exposed to the sun. Stick to the privacy of your own garden though – we don’t want any arrests”.
In previous blogs I briefly reviewed some of the many studies into courtship requests by Dr. Nicolas Guéguen (which you can read here and here). In one of his studies (published in a 2013 issue of Social Influence), Guéguen examined the effect of sunshine on romantic relationships (reasoning that sunny weather puts people in a better mood than non-sunny weather). In this study, an attractive 20-year old man approached young women walking alone in the street and asked them for their telephone number in two conditions (sunny or cloudy days). The temperature was controlled for and all days of the experiment were dry. The results showed that more women gave the man their telephone numbers on the sunny days. Guéguen concluded that positive mood induction by the sun may explain the success in courtship solicitation.
Finally, in his 2009 book Forensic and Medico-legal Aspects of Sexual Crimes and Unusual Sexual Practices, Dr. Aggrawal was quoted as saying that “like allergies, sexual arousal may occur from anything under the sun including the sun”. In fact, Aggrawal’s book arguably contains the most references to fetishes that concern the weather. This includes fetishes and paraphilias in relation to sexual arousal to sunny weather (actirasty), sexual arousal from the cold or winter (cheimaphilia), sexual arousal from snow (chionophilia), sexual arousal from thunderstorms (brontophilia), sexual arousal from thunder and lightning (keraunophilia), sexual arousal from fog (nebulophilia), sexual arousal from rain and being rained upon (ombrophilia and pluviophilia), and love of thunder (tonitrophilia). However, as far as I am aware, no scientific research has ever investigated any of these alleged fetishes.
Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK
Aggrawal A. (2009). Forensic and Medico-legal Aspects of Sexual Crimes and Unusual Sexual Practices. Boca Raton: CRC Press.
Amanad, V. (2012). Does weather affect your sex drive? Only My Health, June 29. http://www.onlymyhealth.com/does-weather-affect-your-sex-drive-1340990772
Guéguen, N. (2013). Weather and courtship behavior: A quasi-experiment with the flirty sunshine. Social Influence, 8, 312-319.
Herbert, E. (2009). Sex: Weather-driven desire? Elle, July 28. Located at: http://www.elle.com/life-love/sex-relationships/sex-tips-women
Hurwood, B.J. (1965). The Golden Age of Erotica. Los Angeles, CA: Sherbourne Press.
Joshi, S. (2010). Summer and intimacy: Felling hot, hot, hot. Complete Wellbeing, May 11. Located at: http://completewellbeing.com/article/feeling-hot-hot-hot/
Lerchbaum, E., Pilz, S., Trummer, C., Rabe, T., Schenk, M., Heijboer, A. C., & Obermayer‐Pietsch, B. (2014). Serum vitamin D levels and hypogonadism in men. Andrology, 2(5), 748-754.
Nimptsch, K., Platz, E. A., Willett, W. C., & Giovannucci, E. (2012). Association between plasma 25‐OH vitamin D and testosterone levels in men. Clinical Endocrinology, 77(1), 106-112.
Rider, S. (2015). How to boost your testosterone levels (the natural way). Coach Magazine, October 5. Located at: http://www.coachmag.co.uk/lifestyle/1558/10-ways-boost-testosterone
Wehr, E., Pilz, S., Boehm, B. O., März, W., & Obermayer‐Pietsch, B. (2010). Association of vitamin D status with serum androgen levels in men. Clinical Endocrinology, 73(2), 243-248.
If the many media reports are to be believed, a 2014 study published in the journal Cell claimed that “sunshine can be addictive like heroin”. In an experiment carried out on mice, a research team led by Dr. Gillian Fell at the Harvard Medical School in Boston (US) reported that ultraviolet exposure leads to elevated endorphin levels (endorphins being the body’s own ‘feel good’ endogenous morphine), that mice experience withdrawal effects after exposure to ultraviolet light, and that chronic ultraviolet causes dependency and ‘addiction-like’ behaviour.
Although the study was carried out on animals, the authors speculated that their findings may help to explain why we love lying in the sun and that in addition to topping up our tans, sunbathing may be the most natural way to satisfy our cravings for a ‘sunshine fix’ in the same way that drug addicts yearn for their drug of choice.
Reading the findings of this study took me back to 1998 when I appeared as a ‘behavioural addiction expert’ on Esther Rantzen’s daytime BBC television show that featured people who claimed they were addicted to tanning (and was dubbed by the researchers on the programme as ‘tanorexia’). I have to admit that none of the case studies on the show appeared to be addicted to tanning at least based on my own behavioural addiction criteria (i.e., salience, mood modification, tolerance, withdrawal, conflict, and relapse) but it did at least alert me to the fact that some people thought sunbathing and tanning was addictive (in fact, the people on the show said their excessive tanning was akin to nicotine addiction).
There certainly appeared to be some similarities between the people interviewed and nicotine addiction in the sense that the ‘tanorexics’ knew they were significantly increasing their chances of getting skin cancer as a direct result of their risky behaviour but felt they were unable to stop doing it (similar to nicotine addicts who know they are increasing the probability of various cancers but also feel unable to stop despite knowing the health risks).
Since then, tanorexia has become a topic for scientific investigation (and I looked at the topic in a previous blog). For instance, in a 2006 study published in the Journal of the American Academy of Dermatology by Dr. Mandeep Kaur and colleagues reported that frequent tanners (those who tanned 8-15 times a month) that took an endorphin blocker normally used to treat drug addictions (i.e., naltrexone) significantly reduced the amount of tanning compared to a control group of light tanners.
A 2005 study published in the Archives of Dermatology by Dr. Molly Warthan and colleagues claimed that a quarter of the sample of 145 “sun worshippers” would qualify as having a substance-related disorder if ultraviolet light was classed as the substance they crave. Their paper also reported that frequent tanners experienced a “loss of control” over their tanning schedule, and displayed a pattern of addiction similar to smokers and alcoholics.
A 2008 study published in the American Journal of Health Behavior by Dr. Carolyn Heckman and colleagues reported that 27% of 400 students they surveyed were classified as “tanning dependent”. The authors claimed that those classed as being tanning dependent had a number of similarities to substance use, including (i) higher prevalence among youth, (ii) an initial perception that the behaviour is image enhancing, (iii) high health risks and disregard for warnings about those risks, and (iv) the activity being mood enhancing.
Another study by Dr. Heckman and her colleagues in the American Journal of Health Promotion surveyed 306 female students and classed 25% of the respondents as ‘tanning dependent’ based upon a self-devised tanning dependence questionnaire. The problem with this and most of the psychological research on tanorexia to date is that almost all of the research is carried out on relatively small convenience samples using self-report and non-psychometrically validated ‘tanning addiction’ instruments.
Based on my own six criteria of behavioural addiction although some studies suggest some of these criteria appear to have been met, I have yet to be convinced that any of the published studies to date show genuine addiction to tanning (i.e., that there is evidence of all my criteria being endorsed) but that doesn’t mean it’s not theoretically possible. However, I’ve just done a study on tanorexia with my research colleagues at the University of Bergen and when we publish our findings I’ll be sure to let my blog readers know about it.
(Please note: A version of this article first appeared in The Conversation and The Washington Post)
Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK
Fell, G.L., Robinson, K.C., Mao, J., Woolf, C.J., & Fisher, D.E. (2014). Skin β-endorphin mediates addiction to UV light. Cell, 157(7), 1527-1534.
Griffiths, M.D. (2005). A ‘components’ model of addiction within a biopsychosocial framework. Journal of Substance Use, 10, 191-197.
Griffiths, M.D. (2014). Sunshine addiction is a hot topic – but does ‘tanorexia’ really exist? The Conversation. June 20. Located at: https://theconversation.com/sunshine-addiction-is-a-hot-topic-but-does-tanorexia-really-exist-28283
Griffiths, M.D. (2014). Sunshine: As addictive as heroin? Washington Post. June 24. Located at http://www.washingtonpost.com/posteverything/wp/2014/06/24/sunshine-as-addictive-as-heroin/
Heckman, C.J., Cohen-Filipic, J., Darlow, S., Kloss, J.D., Manne, S.L., & Munshi, T. (2014). Psychiatric and addictive symptoms of young adult female indoor tanners. American Journal of Health Promotion, 28(3), 168-174.
Heckman, C.J., Darlow, S., Kloss, J.D., Cohen‐Filipic, J., Manne, S.L., Munshi, T., … & Perlis, C. (2014). Measurement of tanning dependence. Journal of the European Academy of Dermatology and Venereology, 28(9), 1179-1185 .
Heckman, C.J., Egleston, B.L., Wilson, D.B., & Ingersoll, K.S. (2008). A preliminary investigation of the predictors of tanning dependence. American Journal of Health Behavior, 32(5), 451-464.
Kaur, M., Liguori, A., Lang, W., Rapp, S.R., Fleischer, A.B., & Feldman, S.R. (2006). Induction of withdrawal-like symptoms in a small randomized, controlled trial of opioid blockade in frequent tanners. Journal of the American Academy of Dermatology, 54(4), 709-711.
Warthan, M.M., Uchida, T., & Wagner, R.F. (2005). UV light tanning as a type of substance-related disorder. Archives of Dermatology, 141(8), 963-966.