Changes in Posttraumatic Stress Disorder Symptoms and Social Withdrawal Coping By Perpetrator Type. Final model, F (3, 114) = 8.61, p < .001. βCSI-Social Withdrawal = .53, p < .001; βperpetrator type = −18, p < .05; βinteraction = −.30, p < .01. PTSD = posttraumatic stress disorder; SW = social withdrawal.