Ghrelin plasma levels during psychopharmacological treatment

The mechanisms underlying weight gain induced by psychopharmacological agents are poorly understood. Because the recently discovered enteric hormone, ghrelin, stimulates food intake, we hypothesized that increases in circulating ghrelin levels might mediate the weight gain caused by certain antidepressants and atypical antipsychotic drugs. Fifty-two patients receiving psychopharmacological treatments were included in the study: 16 patients received antidepressants that are not known to induce weight gain, and 13 patients received mirtazapine or trimipramine, which are antidepressants known to lead to weight gain; 6 patients received clozapine and olanzapine, which have the highest liability among the antipsychotics to cause weight gain, and 17 patients received other antipsychotics. Fasting venous blood samples for the measurement of ghrelin were drawn in the morning between 06:00 and 08:00 a.m. in the second week of treatment. Although psychopharmacological treatment induced significant weight changes in the expected directions (most prominent in the clozapine or olanzapine treatment group), ghrelin levels did not differ significantly between groups. Psychotropic drugs with different propensities to induce body weight gain are associated with similar concentrations of plasma ghrelin in psychiatric patients after a short period of treatment.