Weight change with atypical antipsychotics in the treatment of schizophrenia.

Weight gain is a common complication of antipsychotic treatment. Its consequences include decreased self-esteem, reduced quality of life, reduced adherence with medication and increased morbidity and mortality. Most studies that assess weight change are short term. Among the atypicals mean weight gain is greatest with olanzapine and clozapine and least with aripiprazole and ziprasidone. Mean weight change obscures the marked individual variation in weight change that occurs during antipsychotic treatment i.e. irrespective of the antipsychotic, some subjects lose weight, some maintain their weight and some gain weight. In several long-term naturalistic studies (>6 months) mean weight gain is less marked than in randomised controlled trials of a shorter or comparable duration. This may reflect selective prescribing, the effect of weight management interventions and differences in the statistical analysis employed. With most antipsychotics weight stabilizes in the short to medium term but with clozapine it may continue beyond the first year. With some drugs clinical improvement is associated with short-term weight gain. Predictors of long-term weight gain include lower body mass index, increased appetite and rapid initial weight increase. Weight gain is greater in first onset patients due to the lack of prior antipsychotic exposure and associated weight gain. The potential for weight gain should be discussed with patients before starting antipsychotic treatment and weight monitored regularly during treatment. It may be possible to predict weight gain before an antipsychotic is started or early on in treatment enabling high-risk patients to receive more intensive strategies to reduce weight gain.