Blog Archives

Eat to the beat: What is the relationship between exercise addiction and eating disorders?

In previous blogs I briefly examined both exercise addiction and eating addiction. However, there is some research that these two disorders sometimes co-occur. In some of the papers I have co-written we have reviewed the evidence as to whether exaggerated exercise behaviour is a primary problem in the affected person’s life or whether it emerges as a secondary problem in consequence of another psychological dysfunction. In the former case, the dysfunction is usually classified as primary exercise addiction because it manifests itself as a form of behavioural addiction. In the latter case, it is usually termed as secondary exercise addiction because it co-occurs with another dysfunction, typically with eating disorders, such as anorexia nervosa or bulimia nervosa.

In primary exercise addiction, the motive for over-exercising is typically geared toward avoiding something negative, although the affected individual may be totally unaware of their motivation. It is a form of escape response to a source of disturbing, persistent, and uncontrollable stress. However, in the case of a secondary exercise addiction, the excessive exercise is used as a means of weight loss (in addition to very strict dieting). Thus, secondary exercise addiction has a different etiology than primary exercise addiction. Nevertheless, it should be highlighted that many symptoms and consequences of exercise addiction are similar whether it is a primary or a secondary exercise addiction. The distinguishing feature between the two is that in primary exercise addiction, the exercise is the main objective, whereas in secondary exercise addiction, weight loss is the main objective, while exaggerated exercise is one of the primary means in achieving the objective.

In a qualitative study published by Dr Diane Bamber (University of Cambridge), she and her team interviewed 56 regularly exercising adult women. On the basis of the analysis of the results, the authors identified three factors in the diagnostic criteria of secondary exercise addiction. Among these factors, only the presence of eating disorder symptoms differentiated secondary from primary exercise addiction. The other two factors (i.e., dysfunctional psychological, physical, or social behaviour, and the presence of withdrawal symptoms) were nonspecific to secondary exercise addiction.

However, Dr Michelle Blaydon (formerly of the University of Hong Kong) and colleagues attempted to further sub-classify secondary exercise addiction based on the primary source of the problem, which in their view was related to either a form of eating disorder or to an exaggerated preoccupation with body image. Although this appears to have face validity, to date, there is no empirical evidence for such speculation. Furthermore, a different research study by Dr Diane Bamber found no evidence for primary exercise addiction. In fact, they believe that all problematic exercise behaviours are linked to eating disorders. However, this view remains critically challenged in the literature and there are documented case studies – including one that I published myself back in 1997 where no eating disorders were present at all.

In addition to several studies that have reported disordered eating behaviour often (if not always) accompanied by exaggerated levels of physical exercise, the reverse relationship has also been established. Individuals affected by exercise addiction often (but not always) show an excessive concern about their body image, weight, and control over their diet. This co-morbidity makes it difficult to establish which is the primary disorder. This dilemma has been investigated using trait and personality-oriented investigations. In an early but widely cited controversial study led by Dr Alayne Yates (University of Hawaii) concluded that addicted male long-distance runners resembled anorexic patients on a number of personality dispositions (e.g., introversion, inhibition of anger, high expectations, depression, and excessive use of denial) and labelled the similarity as the “anorexia analogue” hypothesis.

To further test the hypothesis, Yates and colleagues examined the personality characteristics of 60 male obligatory exercisers and then compared their profiles with those of clinical patients diagnosed with anorexia nervosa. While the study did not lend support to the hypothesis, the authors claimed that running and extreme dieting were both dangerous attempts to establish an identity, as either addicted to exercise or anorexic. The study has been criticized for a number of shortcomings, including the lack of supporting data, poor methodology, lack of relevance to the average runner, over-reliance on extreme cases or individuals, and exaggerating the similarities between the groups.

Indeed, later investigations also failed to reveal similarities between the personality characteristics of people affected by exercise addiction and those suffering from eating disorders. Therefore, the anorexia analogue hypothesis has failed to secure empirical support. Numerous studies have further examined the relationship between exercise addiction and eating disorders but no consensus has emerged. One reason for the inconsistent findings may be attributed to the fact that the extent of co-morbidity could vary from case to case depending on personality predispositions, the underlying psychological problem that has led to exercise addiction, and/or the interaction of the two, as well as the form and severity of the eating disorder.

A French study led by Professor Michel Lejoyeaux (Bichat and Maison Blanche Hospital) on 125 Parisian male and female current exercise addicts reported that 70% of their sample were bulimic. In another US study by Dr Patricia Estok and Dr Ellen Rudy among 265 young American adult women runners and non-runners, 25% of those who ran more than 30 miles per week showed a high risk for anorexia nervosa. In studies of people with eating disorders, a study by Peter Lewinsohn (Oregon Research Institute, US) found excessive exercise activity among males with binge eating disorders, but not females. However, the percentage overlap was not reported. Finally, in a review by Marilyn Freimuth (Fielding Graduate University, US), she and her colleagues reported that among people with eating disorders, 39% to 48% also experienced an exercise addiction.

Basically, the major weakness of the literature is the complete lack of large-scale studies. In a recent review of the addiction co-morbidity literature that I did with Dr Steve Sussman and Nadra Lisha (University of Southern California), we didn’t locate a single study on the co-occurrence of exercise addiction with other disorders with a sample size of more than 500 participants.

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

Further reading

Bamber, D.J., Cockerill, I.M., Rodgers, S., & Carroll, D. (2003). Diagnostic criteria for exercise dependence in women. British Journal of Sports Medicine, 37(5), 393–400.

Berczik, K., Szabó, A., Griffiths, M.D., Kurimay, T., Kun, B. & Demetrovics, Z. (2012). Exercise addiction: symptoms, diagnosis, epidemiology, and etiology. Substance Use and Misuse, DOI: 10.3109/10826084.2011.639120.

Blaydon, M.J., & Lindner, K. J. (2002). Eating disorders and exercise dependence in triathletes. Eating Disorders, 10(1), 49-60.

Blaydon, M.J., Lindner, K. J., & Kerr, J. H. (2004). Metamotivational characteristics of exercise dependence and eating disorders in highly active amateur sport participants. Personality and Individual Differences, 36(6), 1419-1432.

Estok, P.J., & Rudy, E.B. (1996). The relationship between eating disorders and running in women. Research in Nursing & Health, 19, 377-387.

Freimuth, M., Waddell, M., Stannard, J., Kelley, S., Kipper, A., Richardson, A., & Szuromi, I. (2008). Expanding the scope of dual diagnosis and co-addictions: Behavioral addictions. Journal of Groups in Addiction & Recovery, 3, 137-160.

Griffiths, M. D. (1997). Exercise addiction: A case study. Addiction Research, 5, 161-168.

Lejoyeux, M., Avril, M., Richoux, C., Embouazza, H., & Nivoli, F. (2008). Prevalence of exercise dependence and other behavioral addictions among clients of a Parisian fitness room. Comprehensive Psychiatry, 49, 353-358.

Lewinsohn, P.M., Seeley, J.R., Moerk, K.C., & Striegel-Moore, R.H. (2002). Gender differences in eating disorder symptoms in young adults. International Journal of Eating Disorders, 32, 426-440.

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.

Szabo, A. (2010). Addiction to exercise: A symptom or a disorder? New York, NY: Nova Science Publishers.

Yates, A., Leehey, K., & Shisslak, C. M. (1983). Running – an analogue of anorexia? New England Journal of Medicine, 308(5), 251-255.

A glutton for reward (rather than punishment)? A brief psychological overview of excessive and addictive eating

In a previous article in this blog on shopping addictions, it was highlighted that the form of excessive or addictive behaviour someone develops may depend upon gender. As I noted in that article, men are more likely to be addicted to drugs, gambling and sex whereas women are more likely to suffer from ‘mall disorders’ such as eating and shopping. Food is – of course – a primary reward as it is necessary for our survival. However, it is this reward that gives highly palatable food (such as sugar) its addictive potential, leading to excessive eating as an addictive behaviour. Possible reasons behind such excessive eating in today’s society are many, including the increasing availability of food, a more inactive lifestyle, and financial considerations. Furthermore, as a means of mood enhancement, food is highly rewarding, easily available, low-cost and most of all it is legal!

Such justifications demonstrate some degree of explanatory power, contributing to research into the topic of excessive eating as an area of increasing interest. However, no such explanations address the critical question of why certain people seem to overeat, despite repeated efforts not to. The majority of obese cases tend to result from an over-consumption of energy, independent from a lack of physical activity. Therefore it may be people, rather than food, that need to be of focus here.

Prevalence rates for excessive and addictive eating are highly variable. Past year prevalence rates of eating disorders (particularly binge eating disorder, among older teens and adults typically varies between 1 to 2% but much higher figures have been reported in a variety of studies in a number of different countries (between 6% and 15% depending upon the sample). Based on these many studies that included samples of at least 500 participants, Professor Steve Sussman, Nadra Lisha (both at the University of Southern California) and myself estimated a past year prevalence rate of 2% for eating addiction among general population U.S. adults.

Reward sensitivity is a personality construct of Jeffrey Gray’s Reinforcement Sensitivity Theory, and is thought to control approach behaviour, by means of the dopamine reward centre. Individuals that are highly sensitive to reward are more prone to detect signals of reward in their environment (such as food) resulting in approaching these rewards more frequently, along with responding quicker and more strongly. Research demonstrates associations between reward sensitivity and increased food cravings, body weight, binge eating, and a preference for high fat food. Such findings offer a possible explanation for why only some individuals eat excessively when reward, particularly that produced by food, is a process available to all.

An excessive appetite for food has long been linked to emotional eating with research demonstrating that refined food addicts specifically report eating when they feel anxious. For instance, this is demonstrated in the eating habits of overweight Americans, revealing that women tend to binge eat when they feel lonely or depressed, while men overeat in positive social situations. Research dating back to the early 1990s found that women being treated for eating disorders described feeling less anxious as an episode of binge eating went on. Such research suggests that highly anxious people are more likely to turn to food for comfort, leading to excessive eating, yet in turn cause themselves more anxiety when this comfort is unavailable. For instance, this is demonstrated in the eating habits of overweight Americans, revealing that women tend to binge eat when they feel lonely or depressed, while men overeat in positive social situations.

Research has shown that obese people score higher on impulsiveness personality scales. Impulsivity is a tendency to ‘act on the spur of the moment’, often associated with a failure to learn from negative experience, wherein individuals know the appropriate way to behave but fail to act accordingly. Refined food addicts eat for a ‘pick-me-up’, although they are aware that they are not hungry, suggesting a correlation between reward sensitivity and impulsive reactions to such reward cues. Impulsive individuals have a tendency to react to stress and anxiety, with a craving for immediate satisfaction as a form of relief. Although eating may deliver this reward or relief, it may then condition impulsive individuals to react quickly, with this inapt response, to such feelings in the future; such as with feelings of hunger when feeling anxious. This could explain why repeated attempts to restrict food intake and lose weight, so often results in relapse in obese people.

Associations have also been observed between self-esteem and a variety of excessive eating behaviour populations, such as restrained eaters, bulimic patients, and binge eaters. One explanation for this suggests that individuals with low self-esteem have lower expectations for personal performance, resulting in less effort being made to resist challenges and temptations to their diets. This offers another explanation that individuals with low self-esteem depend more on external cues to control eating, such as how food looks, rather than internal cues, such as hunger, indicating reward sensitivity and resulting in dieters with low self-esteem overeating. Here, low self-esteem combined with reward sensitivity and its further correlations to impulsivity and anxiety, seem to demonstrate a destructive model of influence on behaviour, one trait further amplifying the next leading to continuous eating to excess.

In relation to low self-esteem, low social desirability has been seen to correlate significantly with restrained eating in obese people. High social desirability is most commonly associated with a desire for thinness. Therefore, although an association with eating behaviour exists, high social desirability is more likely to correlate with anorexic behaviours as opposed to excessive eating. Low social desirability, combined with low self-esteem as a cause or effect, could contribute to explaining excessive eating in some individuals, which in turn could be reasoned by contributions of all traits previously mentioned.

Finally, Professor Elizabeth Hirschman at Rutgers University has proposed a general model of addictive consumption that interrelates excessive and compulsive consumption behaviour. This model suggests similar characteristics people exhibit, along with common causes, patterns of development, and the similar functions such behaviours serve for individuals. Many of these have been previously associated with excessive eating in particular, further suggesting a general consumption personality principle.

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

Further reading

Davenport, K., Houston, J. & Griffiths, M.D. (2012). Excessive eating and compulsive buying behaviours in women: An empirical pilot study examining reward sensitivity, anxiety, impulsivity, self-esteem and social desirability. International Journal of Mental Health and Addiction, DOI 10.1007/s11469-011-9332-7.

Davis, C., Levitan, R. D., Smith, M., Tweed, S. & Curtis, C. (2006) Associations among overeating, overweight, and attention deficit/hyperactivity disorder: A structural equation modelling approach. Eating Behaviors, 7, 266–274.

Hirschman, E.C. (1991) Recovering from drug addiction: A phenomenological account. In Sherry, J.F and Sternthal, B (Eds.), Advances in Consumer Research. Association for Consumer Research, 18, 541-549.

Hodgson R.J., Budd R. & Griffiths M. (2001). Compulsive behaviours (Chapter 15). In H. Helmchen, F.A. Henn, H. Lauter & N. Sartorious (Eds) Contemporary Psychiatry. Vol. 3 (Specific Psychiatric Disorders). pp.240-250. London: Springer.

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.

Trinko, R., Sears, R. M., Guarnieri, D. J. & DiLeone, R. J. (2007) Neural mechanisms underlying obesity and drug addiction. Physiology & Behavior, 91, 499–505.