Psychometric properties of the Specific Phobia Dimensional Scale in an Australian adult community sample

Objective: The Specific Phobia Dimensional Scale (SP-D) is a 10-item scale developed by the Diagnostic and Statistical Manual (Fifth Edition) Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic and Dissociative Disorder work group to supplement current categorical approaches to Specific Phobia (SP) assessment. The aim of the current study was to examine the psychometric properties of the SP-D in an Australian community sample. Method: A total of 285 participants (74% female) aged 18-76 years (M = 28.15; SD = 12.01) completed the study. A smaller subsample (n = 18) completed the measures of interest a second time to examine test-retest reliability. Results: Confirmatory factor analysis indicated a unidimensional factor structure of the SP-D (root mean square error of approximation [RMSE] = 0.13; comparative fit index [CFI] = 0.94). Internal consistency and test-retest reliability was high (a = 0.95 and Intraclass Correlation Coefficient [ICC] = 0.95, respectively). The measure demonstrated adequate convergent validity with the Specific Phobia Questionnaire (SPQ; rs = 0.54), and unsatisfactory divergent validity with the Fear Questionnaire-Agoraphobia subscale (FQ-Ag; rs = 0.45). Conclusions: Overall, the findings suggest that the SP-D can reliably and briefly measure SP symptoms within an Australian community sample. Further research is required to investigate divergent validity. Replication of the test-retest results are required due to small sample size. Overall, this study is limited in its female-biased convenience sample and recruitment methodologies.