Comparison of Olanzapine versus Other Second-Generation Antipsychotics in the Improvement of Insight and Medication Discontinuation Rate in Schizophrenia.

Background: In the last decade, olanzapine became widely used in mental health service worldwide even after being criticized for its metabolic side effects. Patients with schizophrenia on olanzapine were usually found to stay on their medications longer than the other second-generation antipsychotics (SGAs) except clozapine. The reason for this is unknown.

Objective: This prospective study compared the influences of olanzapine and other SGAs except clozapine on improving insight and medication discontinuation rate in schizophrenia.

Methods: A total of 148 patients with schizophrenia medically indicated for initiation of treatment with olanzapine or other SGAs were evaluated for symptoms, insight, attitudes toward medication, side effects, body weight and fasting lipid and glucose parameters at admission and before discharge, and follow-up calls one-year after discharge documented whether they were regularly taking prescribed psychotropic medication or not.

Results: After an average of 72.8 days of inpatient treatment, the olanzapine and other SGAs group exhibited similar levels of symptom improvement with an average reduction of 28.7 in the Positive and Negative Syndrome Scale (PANSS) total score. The Olanzapine group exhibited better improvement in insight assessed using the G12 item of PANSS and Insight and Treatment Attitudes Questionnaire (ITAQ), more metabolic side effects indexed with total cholesterol, triglycerides levels and weight gain, and a lower medication discontinuation rate than the other SGAs group.

Conclusion: Although general symptom improvement was similar, olanzapine significantly improved insight and presented less medication discontinuation compared to other SGAs, which might partially explain why patients on olanzapine stayed longer on their medications.