Horticulture clash: Can gardening be addictive?

Back in November 2000, I appeared in numerous tabloid newspapers around the world in a story about ‘gardening addiction’ (such as one in the Daily Mail – ‘Professor says gardening is addictive’). It all began after I was interviewed by a journalist from the New Scientist magazine (Andy Coghlan). Coghlan wanted my reaction to a study published in the journal Biological Psychology led by my friend and colleague, Dr. Gerhard Meyer (with who I later co-edited the book Problem Gambling in Europe in 2009). Meyer and his colleagues had carried out a study on blackjack players and showed that they increased their heart rates while gambling (something that I also found in an earlier study I published on arousal in slot machine gamblers in a 1993 issue of the journal Addictive Behaviors). Meyer’s study also found that blackjack gamblers playing for money also had increased levels of salivary cortisol compared to blackjack gamblers playing for points.

I was asked by Coghlan whether I thought gambling could be a genuine addiction, even though it didn’t involve the ingestion of a psychoactive substance. I systematically went through my addiction components model (salience, mood modification, tolerance, withdrawal symptoms, conflict, and relapse) and spent about 15 minutes talking about my research on various behavioural addictions. When the New Scientist article was published, the only quote attributed to me was the following:

“Some people say you can’t have addiction unless you take a substance, but I would argue that gambling taken to excess is an addiction. If you accept that, you then accept that sex, computer games, even gardening, can be addictive. It opens up the floodgates to everything else”.

I had quite deliberately used the example of gardening to make the point that addiction should be assessed by standard addiction criteria and that if any behaviour fulfils all the criteria for addiction it should be classed as such irrespective of what the behaviour is. I also said in my interview with the New Scientist that I had never come across a case of gardening addiction but that it was theoretically possible. The New Scientist story was re-written by many different news outlets around the world. My comments were included in all of these stories. Some of these stories were reported with the focus being on the gambling study (such as the one reported by the BBC which you can read here). Others such as the Daily Mail and the New York Post (NYP) made my comments as the focus of the story. Here is what the NYP reported under the headline ‘Garden-variety junkies hooked on hobby’:

“Before you stop to smell the roses, you might want to think twice. People who enjoy gardening are as physically addicted as junkies and alcoholics, researchers claim. The findings by scientists at Bremen University in Germany are controversial because many experts refuse to believe that behavior can be addictive…The scientists also found the same is true of sex and gambling. They studied gamblers and measured the amounts of a stress hormone linked to addiction. Dr. Gerhard Meyer asked 10 gamblers in a casino to play blackjack, staking their own money. While the volunteers played, Meyer measured changes in their heart rates and levels of the stress hormone cortisol in their saliva. He then asked them to play for points rather than money, as a ‘control’ situation. Both heart rates and cortisol concentrations were markedly higher when the gamblers played for money…People who use addictive narcotics also have increased cortisol levels, which, in turn, can trigger the ‘addiction chemicals’ dopamine and seretonin in the brain. ‘Some people say you can’t have addiction unless you take a substance, but I would argue that gambling taken to excess is an addiction’, psychologist Mark Griffiths said. ‘If you accept that, you then accept that sex, computer games, even gardening, can be addictive. It opens up the floodgates to everything else’. If the new research is correct, gardening, gambling and sex, which involve pleasurable rewards for effort expended, could set up an addictive chemical pathway in the brain…Meyer says his findings might reduce the culpability of people who have committed crimes. If lawyers can attribute their clients’ crimes to physiological cravings rather than acts of free will, they may receive lighter sentences, he says”.

I spent much of the week in the media trying to get what I had actually said into context (and even appeared on Channel 4’s Big Breakfast television show defending what I had said). The Daily Mail article had sought comment from TV’s most high profile gardening expert Alan Titchmarsh who said: “[Gardening] is a very addictive pursuit. Once you’ve discovered the thrill of making things grow, you can’t stop. I get very twitchy if I can’t get outside and garden for a few days. It is an addiction – but a positive, useful addiction”. While I have no doubt Titchmarsh believed gardening to be a positive addiction (and would fulfil Dr. Bill Glasser’s criteria for positive addiction that I examined in a previous blog), it wouldn’t be an addiction using my own criteria. I wrote a letter to the New Scientist that they published on November 22 (2000) under the title ‘All kinds of addiction’. In that letter I wrote:

“My alleged comments about gardening addiction have been taken totally out of context and I would like to set the record straight, particularly as many of the national media appeared to have had a laugh at my expense following your press release on this story. My comments were made in reaction to the research by Meyer on gambling addiction, and whether I thought gambling was a true addiction because it didn’t involve a drug. I replied that any behaviour, be it gambling, sex, eating, Internet use, playing computer games or even, theoretically, gardening, that features all the core components of addiction, that is to say, mood-modifying effects, withdrawal symptoms, build-up of tolerance, total preoccupation with the activity, loss of control, neglect of everything else in their lives and relapse can be classed as an addiction. This was not reported in your article, leaving me wide open to misinterpretation. For the record, I have never said that gardening is addictive. What I have said is that any behaviour that fulfils the criteria for addiction can be operationally defined as addiction”.

On the same day (November 22), the Daily Mail also published an edited version of the letter I sent to the New Scientist buried away on page 73 (which you can read here) under the title ‘Eh, not quite’. In retrospect, I can smile about the whole incident, but I wasn’t smiling at the time. In a 2005 paper in the Journal of Substance Use, I subtly included a reference to the ‘gardening addiction’ story (or rather the lack of it) in a paper examining the nature of addiction:

“It is also important to acknowledge that the meanings of ‘addiction’, as the word is understood in both daily and academic usage, are contextual, and socially constructed (Howitt, 1991; Irvine, 1995; Truan, 1993). We must ask whether the term ‘addiction’ actually identifies a distinct phenomenon – something beyond problematic behaviour – whether socially constructed or physiologically based. If so, what are the principal features of this phenomenon? If we argue that it is hypothetically possible to be addicted to anything, it is still necessary to account for the fact that many people become addicted to alcohol but very few to gardening. Implicit within our understanding of the term ‘addiction’ is some measure of the negative consequences that must be experienced in order to justify the use of this word in its academic or clinical context. It seems reasonable at this stage to suggest that a combination of the kinds of rewards (physiological and psychological) and environment (physical, social and cultural) associated with any particular behaviour will have a major effect on determining the likelihood of an excessive level of involvement in any particular activity”.

I have still to come across anyone that I would say is genuinely addicted to gardening. However, I did come across an interesting paper on unusual compulsive behaviours caused by individuals receiving medication for Parkinson’s disease. The paper was published in a 2007 issue of the journal Parkinsonism and Related Disorders by Dr. Andrew McKeon and his colleagues. They reported seven case studies of unusual compulsive behaviours after treating their patients with dopamine agonist therapy (i.e., treatment that activates dopamine receptors in the body). One of the cases involved a man who developed a gardening compulsion:

“A 53-year-old male with [Parkinson’s disease] for 13 years became intensely interested in lawn care. He would use a machine to blow leaves for 6 [hours] without rest, finding it difficult to disengage from the activity, as he found the repetitive behavior soothing. He also developed compulsive gambling”.

This case study at least suggests that someone can develop addictive and/or compulsive like behaviour towards gardening but is obviously isolated and very rare (and in this case brought on by the medication taken). I am not aware of any empirical research on gardening addiction since my comments on the topic back in 2000. However, I still stick to my assertion that if the rewards are present (i.e., psychological, social, physiological, and/or financial), it is theoretically possible for people to become addicted to almost anything – even gardening.

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

Further reading

Glasser, W. (1976). Positive Addictions. New York, NY: Harper & Row.

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

Griffiths, M.D. (1993). Tolerance in gambling: An objective measure using the psychophysiological analysis of male fruit machine gamblers. Addictive Behaviors, 18, 365-372.

Griffiths, M.D. (2000). All kinds of addiction New Scientist, November 22, p 58.

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

Hoffmann, B. (2000). Garden-variety junkies ‘hooked’ on hobby: Study. New York Post, November 10. Located at: http://nypost.com/2000/11/10/garden-variety-junkies-hooked-on-hobby-study/

Howitt, D. (1991). Concerning Psychology. Milton Keynes: Open University Press.

Irvine, J. M. (1995). Reinventing perversion: Sex addiction and cultural anxieties. Journal of the History of Sexuality, 5, 429–450.

Meyer, G., Hauffa, B. P., Schedlowski, M., Pawlak, C., Stadler, M. A., & Exton, M. S. (2000). Casino gambling increases heart rate and salivary cortisol in regular gamblers. Biological Psychiatry, 48(9), 948-953.

Meyer, G., Hayer, T. & Griffiths, M.D. (2009). Problem Gaming in Europe: Challenges, Prevention, and Interventions. New York: Springer.

McKeon, A., Josephs, K. A., Klos, K. J., Hecksel, K., Bower, J. H., Michael Bostwick, J., & Eric Ahlskog, J. (2007). Unusual compulsive behaviors primarily related to dopamine agonist therapy in Parkinson’s disease and multiple system atrophy. Parkinsonism & Related Disorders, 13(8), 516-519.

Truan, F. (1993). Addiction as a social construction: A postempirical view. Journal of Psychology, 127, 489-499.