Assessing daily fluctuations in posttraumatic stress disorder symptoms and substance use with Interactive Voice...

PTSD symptoms and substance use commonly co-occur, but information is limited regarding their interplay. We used ecological momentary assessment (EMA) to capture fluctuations in PTSD symptoms and drinking within and across days. Fifty Iraq and Afghanistan War veterans completed four daily Interactive Voice Response (IVR) assessments of PTSD and substance use with cell phones for 28 days. The aims of this study were to (1) describe participant compliance and reactions to the protocol and (2) identify participant characteristics and protocol reactions that predict compliance. Protocol compliance was high, with participants completing an average of 96 out of a total of 112 IVR assessments (86%). While some participants perceived that the IVR assessments increased their drinking (21%) and PTSD symptoms (60%), self-report measures showed significant decreases in PTSD symptoms and nonsignificant decreases in drinking over the assessment period. Analyses revealed demographic (e.g., older than 24, full-time employment, more education), clinical (e.g., less binge drinking, less avoidance symptoms), and perceived benefit from participation predicted better protocol compliance. Results can guide future research on participant predictors of compliance with intensive EMA methods.