Objective: Atypical antipsychotics, especially clozapine and olanzapine, have been increasingly associated with weight gain and other adverse metabolic events (diabetes mellitus, hyperlipidemia) in non-mentally retarded populations. This report explores the incidence of this phenomenon in an institution-dwelling population of individuals with developmental disabilities.
Method: A retrospective longitudinal analysis was performed for a sample of 41 adults with developmental disabilities and comorbid psychiatric and/or behavioral syndromes for whom treatment was converted from typical antipsychotics to olanzapine or risperidone for a minimum period of 2 years. Data were collected from October 1998 to September 2002. Among parameters analyzed were chlorpromazine equivalent dosage of antipsychotic, metabolic parameters, body mass index (BMI), level of concurrent medications, and concomitant dietary restrictions.
Results: Thirty-two study subjects (78.0%) were men. The mean age of the study subjects was 43.6 years (at the end of the study). Thirty-seven (90.2%) had severe-to-profound mental retardation. Eight (19.5%) were on a restricted diet. Twenty-three subjects (56.1%) were switched from a typical antipsychotic to olanzapine, and 18 subjects (43.9%) were switched from a typical antipsychotic to risperidone. Of the subsample of subjects who were switched from a typical antipsychotic to risperidone, 12 (66.7%) went on to be switched to olanzapine because of either emergent side effects or lack of efficacy. For the overall sample (N = 41), there was a 19.3% increase in chlorpromazine-equivalent antipsychotic dosage from baseline to the 2-year endpoint along with a 5.6% decrease in fasting blood glucose from baseline to the 2-year endpoint. There were no significant differences between baseline and endpoint values for BMI, total cholesterol, low-density lipoprotein cholesterol, or triglycerides.
Conclusion: The findings of this 2-year evaluation suggest that clinically or statistically significant BMI increases as well as blood glucose and lipid elevations are not unavoidably correlated with the use of the atypical antipsychotic agents olanzapine and risperi-done and may be minimized by careful monitoring, a regimen of dietary control, and a moderate activity level in a residential population of individuals with mental retardation.