- This aim is to test the effect of ICBT on symptoms of PTSD and substance use disorders among returning OEF/OIF/OND Veterans seen in a VA clinic. ICBT will be tested with 16 Veterans who meet criteria for both PTSD and substance use disorder at the PTSD or SATP clinics. The investigators propose that ICBT will result in significant reductions in PTSD and substance use severity from baseline to follow-up assessment.