The Schizophrenia Care and Assessment Program Health Questionnaire (SCAP-HQ): An instrument to assess outcomes of schizophrenia care

Abstract

Advances in treatment technologies and development of evidence-based standards of care demand better methods for routine assessment of outcomes for schizophrenia in systems of care. This article describes the development and psychometrics of a new instrument to assess outcomes of routine care for persons with schizophrenia in service systems. Candidate items for the Schizophrenia Care and Assessment Program Health Questionnaire (SCAP-HQ) were drawn from existing measures. Domains covered include disease outcomes (symptoms, subjective medication effects, substance abuse), functional status, health status, quality of life, and public safety. A sample of 1,584 patients with schizophrenia or schizoaffective disorder who were recruited into a large prospective, naturalistic study on the course of treatment for schizophrenia completed the SCAP-HQ at baseline and 1 year later (n = 434), providing data for factor analysis, assessment of internal consistency, convergent validity, and responsiveness to change. A subsample of 121 patients completed a test-retest protocol. Fifteen scales were derived by factor analysis from 55 outcome items on the SCAP-HQ. These factors covered psychiatric symptoms, life satisfaction, instrumental activities of daily living, health-related disability, subjective medication side effects, vitality, legal problems, social relations, mental health-related disability, suicidality, drug and alcohol use, daily activities, victimization, violence, and employment. For most scales, standard psychometric parameters, including internal consistency and test-retest reliability, convergent validity, and responsiveness to change, were acceptable for application to large sample evaluations of care systems. This new measure represents an advance in the development of outcome measures for schizophrenia for use in large-scale studies of routine care.