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Psych Congress  

Adherence to Treatment With Antipsychotic Medications Among Patients With Schizophrenia, Major Depressive Disorder, or Bipolar Disorder

Michael DeGeorge, PharmD
Robert Millet, MD
Patricia Woster, PharmD
Mancia Ko, PharmD
Thomas Smith, MD
Ingenuity Health, a service of Ameritox Ltd.

Objective: To assess potential nonadherence among patients prescribed antipsychotic agents and to identify the use of illicit substances and/or nonprescribed medications in these patients. Methods: Urine samples that were submitted to the laboratory from patients prescribed antipsychotic medications were analyzed for the presence of antipsychotics and/or illicit substances (marijuana metabolite and/or cocaine metabolite) and nonprescribed opioid medications. Samples were classified as positive or negative for the antipsychotic if either parent and/or metabolite(s) were confirmed or not detected, respectively. Antipsychotic medications were tested using liquid chromatography/tandem mass spectrometry. Other drugs were tested using mass spectrometry confirmation following a presumptive positive screening result. Results: Among 3609 urine samples analyzed, 1561, 686, and 1362 samples had a listed diagnosis of schizophrenia, major depressive disorder (MDD), or bipolar disorder (BD), respectively. The proportion of urine samples that tested negative for a prescribed antipsychotic medication was significantly higher for both MDD (32.8%; odds ratio [OR], 2.1; 95% confidence interval [CI], 1.7-2.6) and BD (27.2%; OR, 1.6; 95% CI, 1.3-1.9) groups compared with the schizophrenia group (19.0%). The presence of illicit substances (ie, marijuana, cocaine) and/or nonprescribed medications (ie, opiate, synthetic opioid, benzodiazepine) was detected in significantly more samples from patients with MDD (42.7%; OR, 2.1; 95% CI, 1.7-2.5) or BD (35.2%; OR, 1.5; 95% CI, 1.3-1.8) relative to schizophrenia patients (26.5%). Conclusions: These results indicate that potential antipsychotic medication nonadherence and substance misuse may be even greater among patients with MDD or BD than those with schizophrenia.

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