Antipsychotic drugs and obesity: Is prolactin involved?

Objectives: To correlate the anthropometric indexes (Body Mass Index [BMI] and Waist-Hip ratio [WHR]) with the serum pro-lactin levels in a heterogene ous population of patients treated with typical antipsychotic (AP) drugs. Methods: We evaluated BM, WHR, and fasting serum prolactin of inpatients (n = 105) and outpatients (n = 122) treated with APS, in outpatients receivin g other psychotropic drugs (OPDs) (n = 77), and in drug-free subjects (n = 33). Outpatients had free access to food, whereas the inpatient sample comp rised people with a monotonous diet of approximately 2000 Kcal daily. Results: Prolactin correlated positively with the BM in the whole group of AP-treated outpatient men (P = 0.03) and with the WHR in AP-treated inpatie nt men (P = 0.053). Regarding treatment duration, prolactin and BM correlat ed positively in men consecutively treated for more than 1 year (P = 0.023) . By contrast, a trend toward a negative correlation between prolactin and BMI was observed in AP-treated outpatient women (P = 0.08). No significant correlation, or even a trend, was observed in the other groups. Conclusions: Prolactin may be involved in AP-induced weight gain, particula rly in men. Future studies should characterize thc period of maximal prolac tin impact on body weight during AP treatment. Specific populations particu larly sensitive to hyperprolactinemia might be identified as well. The nega tive correlation between prolactin and BMI detected in AP-treated women res embles the dampened prolactin response observed in severe primary obesity.