Changes in body mass index for individuals with and without schizophrenia, 1987-1996

The advent of the novel or atypical antipsychotic drugs has improved the treatment and quality of life for many individuals. However, many of these newer agents confer a degree of weight gain that is both greater than conventional antipsychotics and of a clinically meaningful magnitude. To better place this issue into perspective, we evaluated body mass index (BMI; kg/m2) levels and the prevalence of overweight and obesity among schizophrenic versus non-schizophrenic individuals among nationally representative samples of the US adult population and evaluated whether there were changes in these rates during the decade from 1987 to 1996, a period in which use of novel/atypical agents increased. Results showed that mean BMI for individuals with schizophrenia is significantly higher than individuals who are not schizophrenic. The non-schizophrenic population shows steady and significant gains in BMI from 1987 to 1996 both as a whole and when stratified by gender and age. In contrast, time trends among the population of schizophrenic individuals show a more complex pattern. Specifically, for most groups, there is little evidence of a general trend in BMI over time. However, among females with schizophrenia ages 18-30, BMI has increased dramatically and significantly causing a much higher obesity rate among young women with schizophrenia in recent years relative to their non-schizophrenic counterparts. The mechanism that underlies this weight age and sex specific time trend is unclear.