CLINICAL HANDBOOK OF SCHIZOPHRENIA

174 III. SOMATIC TREATMENTReports of hyperlipidemia with risperidone and quetiapine are limited, but the likelihoodof these agents causing adverse changes in lipid levels appears lower than that ofclozapine or olanzapine. Similarly, data are too limited to determine definitively the potentialimpact of ziprasidone and the risk of developing dyslipidemia. Nonetheless, ahandful of investigations have reported that ziprasidone does not have an adverse effecton lipid levels and may even lead to beneficial changes in some lipid parameters. Datacurrently available suggest that aripiprazole has a desirable lipid profile. A 26-week trialof 310 patients with chronic schizophrenia investigated the effects of aripiprazole versusplacebo on cholesterol levels. The investigators reported similar changes compared toplacebo in total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein(LDL) cholesterol, and triglycerides. In other studies of aripiprazole in patientswith lipid elevations due to prior antipsychotic treatment, lipid levels often decreased topatients’ baseline levels with the switch to aripiprazole.In summary, some atypical antipsychotics have the ability to increase cholesterol levels,namely, triglyceride levels. The selection of an antipsychotic with a decreased likelihoodof worsening existing dyslipidemia may be an important consideration. Patientswhose cholesterol levels substantially worsen while they receive atypical antipsychotictreatment may need to be switched to an agent with a lower likelihood of elevating cholesterol.In addition, the ability of antipsychotics to produce metabolic side effects such asdyslipidemia necessitates monitoring (see Table 17.2).Diabetes/Glucose IntoleranceThe last several years have seen considerable attention focused on the potential of atypicalantipsychotics to cause new cases of diabetes or to worsen existing diabetes. It is difficultto clearly separate the apparent increase in diabetes risk and use of antipsychotics inpatients with schizophrenia. For instance, the prevalence of diabetes and obesity amongindividuals with schizophrenia appears to be up to two times higher than that of the generalpopulation. Additionally, individuals with psychiatric illness may also have a higherprevalence of impaired glucose tolerance. Cigarette smoking, an extremely common habitin patients with schizophrenia, can exacerbate insulin resistance despite possible reductionsin body weight. Increased visceral adiposity, a risk factor for diabetes, also appearsto be greater in patients with schizophrenia compared to the general public.Numerous case reports and review articles have documented both the onset of newcases of diabetes and worsening of existing diabetes following initiation of treatment withatypical antipsychotics. Retrospective cohort studies have consistently reported that patientsprescribed clozapine and olanzapine are at increased risk of developing diabetescompared to individuals prescribed conventional antipsychotics. The risk associated withrisperidone and quetiapine varies among studies, and limited data for both ziprasidoneand aripiprazole suggest a very limited risk for diabetes. In a group of patients prescribedTABLE 17.2. Monitoring Recommendations for Atypical AntipsychoticsBaseline 4 weeks 8 weeks 12 weeks Quarterly AnnuallyWeight and BMI × × × × ×Waist circumference × ×Blood pressure × × ×Fasting plasma glucose × × ×Fasting lipid profile × × ×Note. BMI, body mass index.