Psychometric properties of the Brazilian version of the Pittsburgh Sleep Quality Index Addendum for PTSD (PSQI-A)

Objective: Sleep disturbances play a fundamental role in the pathophysiology posttraumatic stress disorder (PTSD), and are not only a secondary feature. The aim of this study was to validate and assess the psychometric properties of the Brazilian version of the Pittsburgh Sleep Quality Index Addendum for PTSD (PSQI-A-BR), a self-report instrument designed to assess the frequency of seven disruptive nocturnal behaviors, in a sample of participants with and without PTSD. Methods: PSQI-A was translated into Brazilian Portuguese and applied to a convenience sample of 190 volunteers, with and without PTSD, who had sought treatment for the consequences of a traumatic event. Results: The PSQI-A-BR displayed satisfactory internal consistency (Cronbach's coefficient of 0.83 between all items) and convergent validity with the Clinician Administered PTSD Scale (CAPS), even when excluding sleep-related items (r = 0.52). Test-retest yielded high agreement in the global PSQI-A-BR, with good stability over time (r = 0.88). A global PSQI-A-BR cutoff score of 7 yielded a sensitivity of 79%, specificity of 64%, and a global score of 7 yielded a positive predictive value of 93% for discriminating participants with PTSD from those without PTSD. Conclusion: The PSQI-A-BR is a valid instrument for PTSD assessment, applicable to both clinical and research settings.