Vulnerability to posttraumatic stress disorder

Most individuals will experience a traumatic event during their lives and some will develop subsequent posttraumatic stress disorder (PTSD). PTSD is characterized by symptoms of re-experiencing the traumatic event, avoidance of reminders of the event, and hyperarousal symptoms. The thesis of Miriam Lommen describes six studies related to three different aims. First, two studies aimed to identify individual differences that increase vulnerability to PTSD. Dutch soldiers were tested before and after their deployment to Afghanistan. The results showed reduced fear extinction learning and higher neuroticism scores before deployment predicted PTSD symptom severity after deployment. This suggests that reduced extinction learning and neuroticism are pre-trauma vulnerability factors for PTSD. Second, two studies in the laboratory aimed to understand the mechanisms that contribute to PTSD. Results showed that individuals with high neuroticism scores avoided more ambiguous stimuli than those with low neuroticism scores. This may be the pathogenic mechanism that links neuroticism to PTSD. Third, two studies aimed to test PTSD prevalence in groups that are studied less often, including tsunami survivors in Sri Lanka and patients with schizophrenia. Results showed that PTSD was highly prevalent in these samples. However, PTSD in patients with schizophrenia was often overlooked by clinician