High prevalence of obsessive–compulsive disorder among posttraumatic stress disorder patients

Posttraumatic obsessions have been reported in a few studies and case series. However, the magnitude of this phenomenon is still unknown. In the current study we systematically evaluated the prevalence of OCD in a sample of combat and terror related PTSD patients. Out of 44 referrals, 43% of the participants had PTSD with no OCD and 41% were diagnosed also with OCD. Six percent had sub-threshold OC symptoms. No difference was found between PTSD and PTSD–OCD participants' characteristics (including demographics, trauma-related factors, and other psychiatric co-morbidity). The surprisingly high number of OCD found in the current study suggests that PTSD–OCD might be underdiagnosed, signifies the importance of direct assessment of OCD in patients with PTSD, and raise questions regarding the underlying mechanism of post-traumatic OCD.