Aim 3: To conduct a randomized controlled pilot trial comparing ICBT plus standard Substance Abuse Treatment Program (SATP) or PTSD care versus standard SATP or PTSD care alone, with OEF/OIF/OND Veterans diagnosed with PTSD and substance use disorders, and assess substance use and PTSD outcomes at post treatment and 3-month post treatment follow-up (Stage I Phase III: Randomized Pilot Trial).