Muscling in on body image disorders: What is the nosological status of muscle dysmorphia?

Muscle dysmorphia (MD) is a condition characterised by a preoccupation with the belief that one’s body is insufficiently muscular or lean, or too small and puny (Phillips and Castle, 2001). It afflicts males almost exclusively and has gained ‘official’ status in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) where it is classified as a subtype of body dysmorphic disorder (BDD) which is an illness characterised by a preoccupation with a perceived flaw in appearance associated with distress and psychosocial disability (American Psychiatric Association, 2013). However, in this edition of the Journal, dos Santos Filho et al. (2016) suggest that the current literature does not provide sufficient evidence to support the classification of MD under any existing nosological category: indeed, the authors question its very status as a discrete disorder.

The nosology of MD has been of debate since it was first described as ‘reverse anorexia’ by Pope et al. (1993). There are many descriptions in the scientific literature and lay media about this putative entity, and certainly individuals who meet the DSM-5 diagnostic criteria exist in clinical practice. What has been specifically challenged, however, is the stipulation that a diagnosis of MD is only ‘allowed’ if a diagnosis of an eating disorder does not override it. Indeed, some authors have suggested that MD may be better classified under the heading of eating disorders on the basis, inter alia, that the core feature of MD resembles that of eating disorders, particularly anorexia nervosa (AN), in that a disturbed perception of body image is present. AN and MD also share a number of other features including disordered eating and exercise behaviour, while differences between the two groups are consistent with the opposing physiques strived for in each condition as well as the striking gender difference (Murray et al., 2012). Why, then, is MD not just the ‘male’ variant of AN? One consideration is that the fundamental phenomenological feature of MD is excessive exercising, with disordered eating a secondary feature; however, the reverse is true for AN. Regardless, the categorisation of disorders based on illness symptoms overlooks the underlying neurobiology, of which little is yet known regarding MD.

We suggest another approach, namely, that AN and the eating disorders be grouped with MD and BDD as body image disorders. Indeed, the issue of unhappiness with physical appearance is the very core of these disorders, and arguably all associated behaviours, including eating too much or too little, are driven by a desire to achieve some unrealistic appearance ideal. Similar to the eating disorders, individuals with MD and BDD often do not identify the significant disturbance in their perceived body image and consequently often do not seek treatment independently. The treatments for BDD, MD and eating disorders are also similar, with a focus on cognitive behaviour therapy and serotonergic antidepressants. The behaviours exhibited by these patients are also alike, in that excessive behaviours and mental acts are performed in relation to their perceived physical flaw. Excessive grooming and checking are also common in these conditions, as are compensatory behaviours to try to counter these perceived physical defects. Individuals with BDD employ methods of concealing their perceived flaws and often seek cosmetic surgery in this regard, whereas common features in MD and eating disorders include dietary restrictions and excessive exercise to achieve the respective idealised physiques. Furthermore, the use of anabolic steroids and other illicit compounds used to enhance muscularity in MD, in some ways, parallels the use of stimulants, laxatives and the like used in eating disorders to augment weight reduction. The impact on social functioning seen in eating disorders and MD draws further similarities, with ritualistic food preparation and planning often evident, to the extent where social engagements and recreational activities may be ceased due to fear of disruption to one’s routines and rules.

While definitive classification is likely to continue to be a subject of debate, what is clear is that the distorted perception of one’s body is central to all of the conditions considered in this commentary. In a society whereby body image is a significant cause of concern and distress for many, it is important to try to establish a solid evidence base to allow for accurate diagnosis and classification, and to deliver effective treatments. Greater research specifically identifying the nosological similarities including underlying neurobiology among these illnesses may lead to a more appropriate classification of these conditions under the new categorisation of body image disorders.

See Review by dos Santos Filho et al., 50(4): 322–333.