Bulimia may result from hormonal imbalance

Bulimia is normally regarded as a mental illness that should be treated with cognitive behavioural therapy (CBT).

A newly published thesis from Karolinska Institutet in Sweden, however, shows that the condition depends in certain cases on a hormonal imbalance that can be corrected with common oral contraceptives.

"We have shown that one third of female bulimics have metabolic disorders that may explain the occurrence of the eating disorder. These disorders may in certain cases express the hormonal constitution of the patient, rather than any mental illness", says Dr Sabine Naessen about the research results that are presented in her doctoral thesis.

Bulimia nervosa, compulsive overeating, is probably the most common form of eating disorder, and it is approximately ten times more common in women than in men. The condition is normally considered to have psychological causes, and it is for this reason normally treated with cognitive behavioural therapy and antidepressive drugs.

The results that Dr Naessen has obtained show that bulimia is a complex condition that contains hormonal and genetic components, in addition to psychological components. The bulimics in the studies had higher levels of the male sex hormone testosterone and lower levels of the female sex hormone oestrogen than healthy subjects in the control group had. Testosterone is directly involved in the normal appetite regulation of the body, and an increased level may lead to an increased feeling of hunger.

The testosterone level of patients with bulimia could be reduced by treating these patients with oestrogen-dominated oral contraceptives. The result was that the craving for fat and sugar decreased, as did the feeling of hunger, in approximately half of the bulimics after as short a period of treatment as three months. Three subjects became completely free of the eating disorder as a consequence of the treatment.

"This is a very strong effect. Hormone treatment may very well be an alternative to cognitive behavioural treatment", says Dr Naessen.

Doctoral thesis: "Endocrine and metabolic disorders in bulimic women and effects of antiandrogenic treatment" by S. Naessen, Department of Woman and Child Health.

Download: http://diss.kib.ki.se/2006/91-7357-003-6