Interformat equivalence between paper and electronic administrations of the self-assessment anhedonia scale in a substance use disorder clinical sample

Background The increasing integration of digital tools in clinical practice and research has led to the widespread use of electronically administered questionnaires. However, when a paper-and-pencil (paper-based) instrument is digitized, its original psychometric properties may not be preserved; assessing interformat reliability is essential to ensure data validity. Objective To evaluate the interformat reliability and psychometric equivalence between the original paper-and-pencil Self-Assessment Anhedonia Scale (SAAS-p) and its electronic version (SAAS-e) in individuals with substance use disorders (SUDs). Methods A fixed-order crossover design was used. Fifty-five adults diagnosed with SUDs were recruited from two Addiction Behavior Units during psychotherapeutic treatment. All participants completed both the SAAS-p and SAAS-e. Internal consistency (Cronbach’s α and McDonald’s ω ), interformat reliability (intraclass correlation coefficients, ICCs), and mean score differences were analyzed. Results Both SAAS formats demonstrated excellent internal consistency across the Global Scale, subscales, and dimensions ( α / ω > 0.80, mostly > 0.90). Interformat reliability was high, with all ICCs exceeding 0.97. No significant differences in mean scores were detected between formats except for the Intensity subscale, which showed slightly higher scores in the electronic version; this difference remained within acceptable equivalence thresholds and lacked clinical significance. Conclusion The SAAS-e and SAAS-p show strong psychometric equivalence in patients with SUDs, supporting the reliability of the electronic version and extending evidence of the scale’s validity to a heterogeneous clinical population.