Antipsychotics and schizophrenia, and their relationship to diabetes

Schizophrenia is a major psychiatric disorder with a lifetime prevalence of 1%. Symptoms of schizophrenia include hallucinations, delusions and disordered thoughts (collectively known as positive symptoms) as well as lack of motivation, social withdrawal and apparent lack of emotion (negative symptoms). An individual may experience symptoms from either or both of these categories. Men and women are equally susceptible to the condition, and initial manifestations of the illness typically present during an individual’s teenage or early adulthood years. Schizophrenia is associated with significant increased morbidity and mortality.1 The average life expectancy of an individual with schizophrenia is 62.8 years in UK men and 71.9 years in UK women.2 This is 14.6 and 9.8 years earlier than expected for men and women without mental illness, respectively. Approximately 75% of all deaths in people with schizophrenia are now caused by physical illness, with cardiovascular disease (CVD) being the most common cause of death. All major CVD risks factors, including diabetes, are increased 2to 3-fold in people with schizophrenia.3 Traditional risk factors for type 2 diabetes (T2DM), especially being overweight or obese, are observed more commonly in people with schizophrenia. Forty-two percent of people with schizophrenia had a BMI over 27kg/m2 compared to 27% of the general population in one study.4 Why is this important? Predictors of morbidity and mortality in schizophrenia include T2DM. People with schizophrenia who develop diabetes are in addition more susceptible to the complications associated with the latter. Evidence highlights that they are 74% more likely to develop acute complications and more likely to develop microvascular or macrovascular complications.1 Diabetesrelated deaths are six times more frequent with schizophrenia, contributing to significant excess mortality.5