Investigating the Psychometric Properties of the Severity Measure for Specific Phobia

With the publication of the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, the American Psychiatric Association published several disorder-specific severity measures to support a dimensional approach to disorder classification. The Severity Measure for Specific Phobia – Adult (SMSP; Craske et al., 2013) was designed to provide a dimensional assessment of specific phobia symptoms, but limited psychometric data is currently available for this tool. This study assessed the construct and criterion validity of the SMSP in a sample of adults (n = 67) who self-reported specific phobia symptoms. The SMSP demonstrated excellent internal consistency (Cronbach’s α = 0.93) and statistically significant positive correlations were observed between the SMSP and an associated measure of specific phobia and distress. Statistically significant group differences were observed based on the outcome of a telephone-administered psychodiagnostic interview, such that SMSP scores were higher for participants who met diagnostic criteria for specific phobia than participants who did not (p < .001, d = 1.30). Regression models based on the outcome of the telephone interview indicated that scores on the SMSP uniquely predicted the presence or absence of specific phobia (p < .001) compared to scores from a hypothesized discriminant measure of depression (p = .67). Results provide support for the psychometric utility of the SMSP, though further evaluation of the construct validity of this measure in larger and more diverse samples is warranted.