A new study with twins suggests that for men, the obsession with being too small and undeveloped, known as muscle dysmorphic disorder, may share the same genetic underpinnings as anorexia nervosa.
In five twin pairs, each including one male with anorexia nervosa, Finnish researchers found a "striking familial liability" for traits related to the eating disorder, including major depression, muscle dysmorphic disorder (sometimes called "bigorexia"), and obsessive compulsive disorder. The findings suggest that all of the symptoms have similar genetic roots, the researchers point out.
Anorexia nervosa is rare in men, and the course of the disease is poorly understood, Dr Anu Raevuori of the University of Helsinki in Finland and colleagues note. To better understand how the illness progresses in men, and to examine the potential familial factors, they identified the five twin pairs from a group of 2 122 male twins born in Finland between 1975 and 1979.
Each of the five men with anorexia had been overweight before age 17, but all of their co-twins were normal weight in their early 20s. "The early overweight in otherwise vulnerable males seemed to have had a crucial role in triggering the dieting, which, in turn, led to anorexia nervosa," the researchers write in the International Journal of Eating Disorders.
Eating disorder "distressing"
Four of the men with anorexia and four of the co-twins had a lifetime affective disorder, which was major depression for all but one of them. In all of the anorexia nervosa patients, the eating disorder preceded the onset of depression.
Just two of the individuals with anorexia nervosa underwent treatment. While all recovered from the illness, they retained some symptoms including muscle dysmorphia, obsessive weight-lifting, and the use of protein powders and other supplements intended to build muscle.
Even though all of the men had anorexia for a relatively short time, Raevuori and colleagues note, they said that their bout with the eating disorder was "an especially distressing period" in their lives.
"Feelings of shame, isolation and alienation were ubiquitous among them and appeared to result from the double stigma of having not only a mental illness, but also a 'woman's illness'," the researchers conclude. – (Reuters Health)
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