The purpose of this study is 1) to evaluate whether massing 10 PE sessions in 2 weeks (massed trials; M-PE) is more efficacious than Minimal Contact control (MCC); 2) whether the massed sessions format retains the efficacy of treatment compared to 10 PE sessions spaced over 8 weeks (spaced trials; S-PE), and 3) to evaluate for the first time the efficacy of the 10 PE sessions delivered in 8 weeks in an active duty population by comparing it to an active comparison condition, Present-Centered Therapy (PCT).