Social Support Moderates the Association Between Posttraumatic Stress Disorder Treatment Duration and Treatment Outcomes in Telemedicine-Based Treatment Among Rural Veterans

For patients participating in trauma-focused psychotherapies for posttraumatic stress disorder (PTSD), such as cognitive processing therapy (CPT), pretreatment characteristics may moderate treatment effectiveness. For instance, preexisting supportive relationships may encourage skill utilization or provide contrasts to maladaptive cognitive biases highlighted in trauma-focused treatments for PTSD. Such pretreatment characteristics are important to study in rural individuals, who may experience barriers to initiating and completing treatment. The aim of this study was to examine whether pretreatment social support, measured using the Medical Outcomes Study Social Support Survey, would moderate the association between CPT duration (i.e., number of sessions attended) and change in PTSD symptoms, using data from a pragmatic randomized controlled trial of a telemedicine-based collaborative care intervention for rural veterans (N = 225). Social support moderated the association between CPT duration and PTSD symptom change, B = −0.016, SE = −.006; 95% CI [−0.028, −0.005], such that increased duration was associated with more PTSD symptom change only at average or higher levels of support. This effect was found for overall and emotional support but not tangible support. Additionally, on average, among participants who attended eight or more CPT sessions, only those at or above 1 standard deviation above the mean social support score demonstrated a reliable change in PTSD symptoms. The results indicate that the link between CPT treatment duration and treatment outcomes may be stronger for veterans with higher levels of pretreatment social support.