Antipsychotic adherence, switching, and health care service utilization among Medicaid recipients with schizophrenia.

Objective: To evaluate health care resource utilization in patients with schizophrenia who continued newly prescribed antipsychotic medications, compared with those switching to different treatments.

Methods: Adults with schizophrenia in the California Medicaid (MediCal) database who initiated treatment with index medications in 1998-2001, were classified as having: 1) abandoned antipsychotic medications; 2) switched to another medication; or 3) continued with the index antipsychotic, for up to 6 months after the index date.

Results: Of 2300 patients meeting eligibility criteria, 1382 (60.1%) continued index medications, 480 (20.9%) switched, and 438 (19.0%) abandoned antipsychotic treatment. Utilization in several resource categories occurred significantly more frequently among patients whose regimens were switched (vs those continuing index medications). These included using psychiatric (24.2% vs 14.5%; P < 0.001) or nonpsychiatric (31.5% vs 24.3%; P < 0.05) emergency services; being admitted to a hospital (10.6% vs 7.4%; P < 0.05); making nonpsychiatric outpatient hospital visits (43.3% vs 36.4%; P < 0.05) or nonpsychiatric physician visits (62.7% vs 56.4%; P < 0.05); and using other outpatient psychiatric (53.3% vs 40.7%; P < 0.001) or nonpsychiatric (82.7% vs 74.6%; P < 0.001) services.

Conclusions: Switching antipsychotic medications is associated with significantly increased health care resource utilization (vs continuing treatment).