The Beliefs About Medication Scale: Development, Reliability, and Validity

The purpose of the study was to develop and evaluate a psychometrically sound health belief measure, the Beliefs About Medication Scale (BAMS) that can be used with adolescent chronic illness populations whose prescribed treatment includes oral medication. One hundred and thirty-three adolescents (age 11–18 years) with asthma (n = 60), HIV (n = 31), or inflammatory bowel disease (n = 42) completed the BAMS and, along with their parent, a self-report medication interview. A confirmatory factor analysis supported the hypothesized subscales of Perceived Threat, Positive Outcome Expectancy, Negative Outcome Expectancy, and Intent to Adhere to treatment. The subscales evidenced good internal consistency and 3-week test-retest reliability. Univariate and multivariate analyses demonstrated that the health belief constructs accounted for 22% of the variance in medication adherence beyond demographic and illness characteristics. The study provides preliminary evidence of the reliability and validity of a theoretically based measure of health beliefs for adolescents. The BAMS may be a useful tool to evaluate the psychological barriers to adherence that place teenagers at risk for nonadherence.