Tuesday, September 16, 2014
Now, a thoughtful paper by Johannes Hebebrand and colleagues, published in Neuroscience & Biobehavioral Reviews, argues that there is in fact little evidence for addiction to “food” per se (as you would see in addiction to a specific substance) and that therefore, it may be better to describe the addiction-like overconsumption of food as a behavioural addiction, in this case, an addiction to eating.
“Eating is intrinsically rewarding and reinforcing, and food consumption is well-known to activate the reward system in the brain; this applies particularly in the physiological state of hunger. It is easy to see that the rewarding properties of food and their activation of the reward pathway might lead intuitively to the idea that food substances may have addictive properties. However, just because eating behavior engages these reward systems, it does not necessarily follow that specific nutrients (substances) are able to evoke a substance addiction. Instead, the complex activation of the reward system as the initial step of the process ending in addiction can be viewed as being dependent on eating (subjectively) palatable foods irrespective of their nutritional/chemical composition.”
“Per se, foods are nutritionally complex and there is hardly any evidence to suggest that under normal physiological circumstances humans crave specific foods in order to ingest a specific ‘substance’. Instead, the diet of subjects who overeat typically contains a broad range of different, subjectively palatable foods. It can be argued that access to a diversity of foods, especially a diverse range of palatable foods, may be a pre-requisite for the development of addictive-like eating behavior.”
“There is currently no evidence that single nutritional substances can elicit a Substance Use Disorder in humans according to DSM 5 criteria. In light of the lack of clinical studies that have aimed to detect addictions to specific nutrients, it cannot as yet be ruled out that a predisposed subgroup does indeed develop such a substance based addiction, which in theory may be substantially weaker than in the case of addictions based on well-known exogenous substances such as alcohol, cannabis, nicotine or opiates. The fact, that clinical case studies do not abound on an addiction like intake of specific nutrients or even specific foods, would suggest that such cases are rare, if they exist at all. Alternatively, the addiction is so weak that it is not adequately perceived and reported as such. This leads to the question as to the boundaries between excessive consumption and the beginning of a true addiction.”
“…there is very little evidence to indicate that humans can develop a “Glucose/Sucrose/Fructose Use Disorder” as a diagnosis within the DSM-5 category Substance Use Disorders. We do, however, view both rodent and human data as consistent with the existence of addictive eating behavior. The novel DSM-5 (APA, 2013) currently does not allow the classification of an “Overeating Disorder” or an “Addictive Eating Disorder” within the diagnostic category Substance-Related and Addictive Disorders; indeed, the current knowledge of addictive eating behaviors does not warrant such a diagnosis. However, efforts should be made to operationalize the diagnostic criteria for such a disorder and to test its reliability and validity. It needs to be determined if such a disorder can occur distinct from other mental disorders.”
Overall I believe that reframing the perceived loss of control over food intake often reported by my patients as a “behavioural” rather than a “substance” addiction may be helpful in approaching this rather complex topic and may well open the path to novel therapeutic approaches more consistent with our current understanding of behavioural addictions.
Hebebrand J, Albayrak O, Adan R, Antel J, Dieguez C, de Jong J, Leng G, Menzies J, Mercer JG, Murphy M, van der Plasse G, & Dickson SL (2014). “Eating addiction”, rather than “food addiction”, better captures addictive-like eating behavior. Neuroscience and biobehavioral reviews PMID: 25205078