Type 2 diabetes mellitus induced by an atypical antipsychotic medication.

Diabetes and mental disorders are common chronic illnesses in the United States, affecting more than 16 million and 44.3 million Americans, respectively. As a result of the ever-increasing incidence of obesity, diabetes is being diagnosed more often, not only in the adult population but also in children. Additionally, more focus is being given to behavioral disorders in recent years, and the Healthy People 2010mental health initiative is being favorably reviewed and accepted in the medical community. Consequently, such conditions as bipolar and major depression are being diagnosed and treated more often in the primary care setting. Recently, the introduction of the new class of atypical antipsychotic medications has been a major treatment advance for patients with affective disorders. These agents are being prescribed for the treatment of behavioral disorders because they provide clinically effective therapies without some of the side effects that are associated with older agents, such as the phenothiazine class of antipsychotic medications. These side effects often include extrapyramidal symptoms, of which several can be irreversible. Because of the increased use of the atypical antipsychotic medications, new and unanticipated side effects have appeared. Specifically, atypical antipsychotic drugs have been associated with new-onset diabetes and weight gain. These side effects have involved such agents as clozapine, olanzapine, quetiapine, and a combination of clozapine and quetiapine. The development of diabetes has been reported to occur anywhere from 10 days to 18 months after starting therapy. One theory is that diabetes might result from the weight gain caused by these agents. Other studies suggest that these agents affect glucose transport metabolism peripherally in patients, possibly increasing the potential for hyperinsulinemia and peripheral insulin resistance. Further hypotheses point to the activity of atypical antipsychotic drugs at the serotonin receptors of the beta cells in the pancreas, more specifically 5HT1A and 5HT2 receptors. This activity might lead to derangement of beta cell function, with resulting increases in glucose levels in patients. A case is described of a patient who developed new-onset diabetes shortly after starting an atypical antipsychotic drug. This case differs from previous ones in that we report the temporal association of the medications and onset of diabetes, and we offer possible explanations for the onset of diabetes and management techniques from a primary care standpoint.