Avoidant Personality Disorder Severity Index: Dimensional structure and psychometric properties

Introduction: The Avoidant Personality Disorder Severity Index (AVPDSI) is developed to provide a standardized clinical interview to measure the severity of and changes in manifestations of avoidant personality disorder (AVPD) in terms of behavior and anxiety, as defined in the Diagnostic and Statistical Manual of Mental Disorders-IV/5 (DSM-IV/5). This first assessment of the AVPDSI examined its dimensional structure and psychometric properties. 

Methods: We investigated factor structure, reliability, interrater reliability, validity, clinical cutoff scores, and sensitivity to change in a mixed sample of patients with a primary diagnosis of AVPD, borderline personality disorder (BPD), social anxiety disorder (SAD), panic disorder (PAD) and in non-patients (NP) (n = 305). 

Results: The underlying structure indicated a behavior and anxiety dimension. The instrument showed good internal reliability, inter-rater agreement, and a clinical cutoff point with good sensitivity and specificity. Convergent and discriminant validity were good and preliminary results in a treated subsample (n = 20) indicated sensitivity to change. 

Conclusion: In our opinion, a new and valid instrument has been introduced, enabling researchers and clinicians to reliably measure the severity of and changes in manifestations of AVPD.