Low leptin levels but normal body mass indices in patients with depressionor schizophrenia

Appetite, food intake and weight are frequently altered in psychiatric diso rders such as major depression and schizophrenia. The few studies investiga ting weight and the body mass index (BMI) have yielded variable results, Le ptin, a fat cell-derived hormone signalling to the brain the size of the ad ipose tissue, plays a pivotal role in the regulation of weight and food int ake. Moreover, leptin is involved in the control of other behaviors and in brain development. There is almost no information about the amounts of circ ulating leptin in major depression or schizophrenia. We investigated the BM I and plasma leptin levels in patients with major depression (n = 62), schi zophrenia (n = 42), and in healthy controls (n = 64). Mean BMIs did not dif fer between groups. However, leptin levels were significantly lower in both patient groups compared to healthy controls. Moreover, patients suffering from schizophrenia showed significantly lower leptin levels than depressed patients. Decreased leptin levels were independent of psychotropic medicati on, We conclude that depression and schizophrenia go along with decreased s ystemic leptin concentrations that cannot be explained by medication or an altered BMI. Hence, leptin might play an important pathophysiological role in these psychiatric disorders that deserves further scientific attention. Copyright (C) 2001 S. Karger AG. Basel.