The second generation antipsychotic medicines such as clozapine and olanzapine are the most effective treatment for schizophrenia and as such they are widely used drugs. However, one of the side effects of the drugs is obesity and metabolic derangements characteristic of Type-2 diabetes. Therefore these drugs could be making a significant contribution to the increased incidence of Type-2 diabetes in recent times. It was long assumed that these metabolic defects were secondary to the obesity that developed but our work in rats found that these drugs acutely induce defects in glucose metabolism. However, these differ from those seen in type-2 diabetes in that they appear to be driven by hyposecretion of GLP-1 and hypersecretion of glucagon that causes a subsequent increase in hepatic glucose release and thus a flow on effect on insulin secretion. We are now in the process of replicating these studies in humans and will report the preliminary results of these studies at the ANZOS meeting