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Triple-combination therapy for schizophrenia may increase risk for type 2 diabetes

Patients with schizophrenia taking a combination of at least three different classes of psychiatric drugs had a higher risk for developing type 2 diabetes compared with those taking first-generation antipsychotics alone, findings published in BMC Psychiatry showed.

“Antidepressants and mood stabilizers have been individually associated with type 2 diabetes risk,” Vasiliki Mamakou, MD, of National and Kapodistrian University Athens Medical School, and Dromokaiteio Psychiatric Hospital, and colleagues wrote. “A better understanding of the underlying mechanism linking [type 2 diabetes] and psychiatric disorders can provide evidence and help shape strategies for the prevention of [type 2 diabetes] in this group of patients.”

In this case-control study, known as the Genetic Overlap between Metabolic and Psychiatric disease study, researchers examined the link between pharmacological treatment and the risk for type 2 diabetes in hospitalized Greek patients with schizophrenia. The investigators evaluated the effects of psychotropic medication, BMI, duration of schizophrenia, number of hospitalizations and physical activity on risk for type 2 diabetes in 1,653 patients with schizophrenia, 611 with type 2 diabetes and 1,042 without diabetes.

Participants were included in the study if they had received one of the following non-overlapping treatment categories consistently for at least 6 months:

• monotherapy with first-generation antipsychotics (n = 373);

• monotherapy with second-generation antipsychotics (n = 215);

• combined therapy of two psychiatric drugs, one of which was an antipsychotic and the other an antipsychotic, antidepressant or mood stabilizer (n = 570); and

• triple or more psychiatric medications, one of which was an antipsychotic (n = 232).

After adjusting for age, BMI, sex, duration of schizophrenia and number of hospitalizations, analysis revealed that patients with schizophrenia who were taking a combination of at least three different classes of psychiatric drugs were more likely to develop type 2 diabetes than those taking first-generation antipsychotic therapy alone (OR = 1.81; 95% CI, 1.22–2.69).

However, there was no link between second-generation antipsychotic use or the combination of drugs belonging to two different classes of psychiatric medications and an increased risk for type 2 diabetes compared with first-generation antipsychotic use.

“Given the widespread use of combined categories of psychiatric medications, we suggest future studies should prospectively explore the effect of different treatment options on type 2 diabetes incidences, in order to formulate clinical guidelines,” Mamakou and colleagues wrote. “Future studies should [also] explore the research hypothesis that maximization of monotherapy doses or switch to a different antipsychotic class may be associated with decreased diabetogenic effect as compared with the addition of multiple antipsychotic medications.” – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.