Mental health articles

Genetic factors

Genetic factors may contribute to risk for both anorexia and bulimia. Klump et al., for example, estimated 74 per cent of the variance in anorexic behaviours to be attributable to genetic factors, following a twin study in which they found 50 per cent of MZ twins and no DZ twins to be concordant for anorexia. Similarly, Kendler et al. found the rate of concordance for bulimia between MZ twins to be higher than that between DZ twins, although the concordance rates for both groups were relatively low: 23 and 9 per cent respectively. In addition to genetic risk for eating disorders, Keel et al. found evidence of shared genetic risk for both eating and anxiety disorders in a large-scale twin study involving nearly 700 twins. Genetic studies have now moved from family studies, indicating potential genetic processes, to examination of actual genes. Key genes identifi ed as being involved in eating disorders appear to control serotonin metabolism, with particular attention given to various alleles of the serotonin 5-HT(2A) receptor gene– although other variants have also been studied. The dopamine receptor genes D2/D3 and DRD4 also seem to be implicated.

Tags: anorexia, bulimia, genetic