Prescribing more than one antipsychotic at the same time is becoming common in the treatment of patients with severe mental illness (SMI), although most guidelines recommend monotherapy.

The aim of this study was to examine the prevalence of antipsychotic polypharmacy and to compare the practices of polypharmacy and monotheraphy in terms of the rationale and compatibility of the treatment.

This study included 235 patients with SMI between 18 and 65 years of age who were followed at KTU Psychiatry Department Schizophrenia-Bipolar Disorder outpatient clinic between January 2007 and December 2014. The sociodemographic and clinical data were evaluated by a chart review form which was prepared by the researcher and designed according to American Psychiatric Association treatment algorithm and National Associated Mental Health Program Directors polypharmacy classification.

138 patients (58.7%) were diagnosed with schizophrenia, 75 patients (31.9%) were diagnosed with bipolar disorder and 22 patients (9.4%) were diagnosed with schizoaffective disorder. 62 patients (26.4%) were receiving antipsychotic polypharmacy. Combinations of two second-generation antipsychotics were most common. Anticholinergic drug use was significantly more common in patients on antipsychotic polypharmacy. Reported adverse events were more common in patients on polypharmacy but did not reach the level of statistical significance. Patients on antipsychotic polypharmacy were more likely to be diagnosed with schizophrenia. Polypharmacy patients were also more likely to receive clozapine and amisulpride whereas monotherapy patients were more likely to receive olanzapine.

Our results confirm previous reports that indicate patients with SMI are most likely to receive antipsychotic polypharmacy.

The authors have not supplied their declaration of competing interest.