Interventions to reduce weight gain in schizophrenia

Weight gain is common for people with schizophrenia and this has serious implications for health and well being.

To determine the effects of both pharmacological (excluding medication switching) and non pharmacological strategies for reducing or preventing weight gain in people with schizophrenia.

We searched key databases and the Cochrane Schizophrenia Group's trials register (April 2006), reference sections within relevant papers, hand searched key journals, and contacted the first author of each relevant study and other experts to collect further information.

We included all clinical randomised controlled trials comparing any pharmacological or non pharmacological intervention for weight gain (diet and exercise counselling) with standard care or other treatments for people with schizophrenia or schizophrenia-like illnesses.

We reliably selected, quality assessed and extracted data from studies. As weight is a continuous outcome measurement, weighted mean differences (WMD) of the change from baseline were calculated. The primary outcome measure was weight loss.

Twenty-three randomised controlled trials met the inclusion criteria for this review. Five trials assessed a cognitive/behavioural intervention and eighteen assessed a pharmacological adjunct. In terms of prevention, two cognitive/behavioural trials showed significant treatment effect (mean weight change) at end of treatment (n=104, 2 RCTs, WMD -3.38 kg CI -4.2 to -2.0). Pharmacological adjunct treatments were significant with a modest prevention of weight gain (n=274, 6 RCTs, WMD - 1.16 kg CI -1.9 to -0.4). In terms of treatments for weight loss, we found significantly greater weight reduction in the cognitive behavioural intervention group (n=129, 3 RCTs, WMD -1.69 kg CI -2.8 to -0.6) compared with standard care.

Modest weight loss can be achieved with selective pharmacological and non pharmacological interventions. However, interpretation is limited by the small number of studies, small sample size, short study duration and by variability of the interventions themselves, their intensity and duration. Future studies adequately powered, with longer treatment duration and rigorous methodology will be needed in further evaluating the efficacy and safety of weight loss interventions for moderating weight gain. At this stage, there is insufficient evidence to support the general use of pharmacological interventions for weight management in people with schizophrenia.