Using the Theory of Planned Behavior to Improve Treatment Adherence in Mexican Americans with Schizophrenia


Failure to adhere to treatment with antipsychotic medication is the most common cause of relapse among patients with schizophrenia. A novel multi-family group (MFG) intervention, informed by the Theory of Planned Behavior (TPB), demonstrated efficacy in increasing medication adherence and decreasing re-hospitalizations in schizophrenia patients. This report explores the hypothesis that the improved outcomes obtained through the MFG approach were mediated by changes in the patients’ attitudes towards medications, subjective norms-social influences, and perceived behavioral control of resources.


Data from a recently completed, randomized controlled trial of MFG was used to test the hypothesis that the improvement in adherence was mediated by the three TPB factors. Subjects were 174 Mexican American adults with schizophrenia-spectrum disorder who had participated in a study of MFG focused on improving medication adherence. Assessments occurred at baseline and at 4, 8, 12, 18 and 24 months.


Path analysis revealed that the increased adherence associated with MFG was mediated by improvements in subjective norms but not attitudes towards medications nor perceived behavioral control.


An MFG treatment specifically tailored to increase medication adherence among Mexican Americans with schizophrenia achieved its benefits by leveraging social influences through teaching family members how to support medication adherence in their ill relatives. 

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Home of the Culturally Adapted Psychoeducation project for families of patients with first-episode psychosis and The Culture and Psychosis Working Group