Predictors of antipsychotic-induced weight gain in first-episode psychosis: conclusions from a randomized, double-blind, controlled prospective study of olanzapine, risperidone, and haloperidol.

BACKGROUND

Antipsychotic-induced weight gain is one of the most distressing adverse effects being observed in recent times. Most studies have been limited by several confounders.

AIM

To evaluate the predictors of antipsychotic-induced weight gain in drug-naive patients with first-episode psychosis treated with olanzapine, risperidone, or haloperidol and compare them with a healthy matched control group.

METHODS

Newly diagnosed patients with first-episode schizophrenia treated with antipsychotic medication-olanzapine, risperidone, or haloperidol-and matched healthy controls were followed for 6 weeks. Body mass index (BMI), waist circumference, and weight changes and proportions of subjects with more than 7% weight gain were calculated. The predictors of weight gain were explored.

RESULTS

Ninety-nine patients with first-episode schizophrenia and 51 healthy controls were examined. Waist circumference (r = -0.25; P < 0.01) and weight (r = -0.24; P < 0.01) at baseline in addition to the disease process (P < 0.001) as well as antipsychotic use (P < 0.001) were associated with greater increases in weight and BMI. Olanzapine (77%) had greater clinically significant weight gain as compared with risperidone (63%) and haloperidol (22%). Lower BMI at baseline and a diagnosis of undifferentiated schizophrenia were associated with antipsychotic-induced weight gain.

CONCLUSIONS

The results confirm clinically significant and substantial weight gain induced by antipsychotic treatment in drug-naive patients with first-episode schizophrenia and identify several risk factors for weight gain such as lower BMI scores, use of olanzapine, and a diagnosis of undifferentiated schizophrenia.