Association between antipsychotics and weight gain among psychiatric outpatients in Pakistan: a retrospective cohort study

We performed a case note review of all patients who had been prescribed antipsychotic medication at the psychiatry outpatient clinic of a tertiary care university hospital in Pakistan over a 4-year period.A total of 50% of patients had a BMI in the overweight or higher range at baseline. Patients showed a mean weight gain of 1.88 kg from baseline in 3 months and 3.29 kg in 6 months. Both of these values were statistically significant. The increase in mean BMI from baseline was 0.74 and 1.3 in 3 months and 6 months, respectively. In patients for whom we had at least one further weight measurement after baseline, 48% (39/81) showed a clinically significant weight gain.Pakistani patients are just as likely to put on weight during antipsychotic treatment as patients from other countries. Considering that this population already has a much higher prevalence of diabetes mellitus compared to the Western countries, the consequences of increased weight may be even more serious in terms of increased morbidity and mortality.The mortality rate of people suffering from schizophrenia has been estimated to be twice as high as in the general population[1]. More than two thirds of this excess mortality is due to 'natural' causes[2], with death due to cardiovascular complications being the leading cause of this excess mortality[3].The first reports of an increased risk of impaired glucose tolerance in people suffering from schizophrenia appeared in the literature several years before the first antipsychotic became available[4,5]. Soon after chlorpromazine was discovered reports suggesting an association between chlorpromazine and diabetes started appearing[6]. Since then many studies have been published firmly establishing a clear link between antipsychotics and diabetes mellitus, more with atypical than typical antipsychotics [7-10]. This led to a US Food and Drug Administration (FDA) recommendation in 2003 for including a warning about association with hyperglycaemia and diabetes o