Effect of atypical antipsychotics on body weight in geriatric psychiatric inpatients

Background: Studies suggest that antipsychotic-induced weight gain is not a great concern in the elderly population. This study investigated the weight change in elderly patients with various treatment duration and antipsychotics. Part 1 of the study was to determine whether atypical antipsychotics induced weight change in elderly patients. Part 2 was to determine whether certain atypical antipsychotics induced more weight change in elderly patients. Methods: In Part 1, a retrospective chart review was done on 115 geriatric inpatients. After exclusion, patients were divided into four groups: control ( n = 17), new treatment ( n = 18), long-term treatment ( n = 13), and medication switch groups ( n = 8). In Part 2, a retrospective medication review was performed on 169 geriatric inpatients. After exclusion, patients were divided into three groups: aripiprazole ( n = 18), olanzapine ( n = 49), and risperidone ( n = 57). Body weights were obtained at two different time points. Results: No significant difference in weight change was observed among the control (1.5 kg), new treatment (0.8 kg), long-term treatment (−0.3 kg), and medication switch (1.9 kg) groups. No significant difference in weight change was observed between patients with and without dementia (0.8 and 1.1 kg, respectively). The weight change in the aripiprazole group (−2.0 kg; −2.30% from baseline) was significantly different from the weight change in the olanzapine group (0.7 kg; 1.87% from baseline; p < 0.05), but not from the risperidone group (−0.4 kg; −0.45% from baseline). Clinically significant weight gain (>7% increase in body weight) occurred in 14.3% of the olanzapine patients, a percentage significantly higher than the 3.5% in the risperidone group. Conclusion: Although atypical antipsychotics were generally weight neutral in the geriatric population, aripiprazole and olanzapine were associated with significant weight loss and weight gain, respectively.