The Reliability & Validity of Outcome Measures for Assessing Psychosis in Adolescents.


M. Munroe, N. Browne, S. Archie, E. Gardizi

Background: The routine use of outcome measures, such as scales, assessing the mental state is thought to improve decision making and patient care in the treatment of individuals with psychosis.

Objectives: Evaluate the reliability and validity of scales currently being used by five early intervention psychosis programs at university-based centres in Ontario. The outcome measures represented the following domains: symptoms, functioning, quality of life, and substance use

Method: Literature searches were conducted on the outcome measures to obtain reliability and validity data for each scale. Reliability was based on inter-rater reliability and reproducibility. Validity was compared to a ‘gold standard’ and sensitivity to change. The outcome measures were ranked regarding inter-rater or construct validity, from minimal (<0.2) to almost perfect level of agreement (>0.9).

Results: Almost perfect to moderate inter-rater reliability and construct validity ratings were obtained for many of the scales. Only the Global Assessment of Functioning (GAF) Scale displayed a minimal level of agreement.

Conclusions: Most of the measures demonstrated excellent psychometric properties for assessing outcomes for first episode psychosis patients.

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