this can vary by patient. I suffered from PTSD for about a year after a traumatic incident, and found indicas like kush's and grape ape helped me. But I have a friend who works specifically with veterans with PTSD and finds there is a wide variety of preferences for PTSD patients from heady energetic sativas to sleep inducing indicas. It really depends on your personal biochemistry. But if you want to see what has worked for others, check out sites like leafly.com or cannasos.com where you can search for strains based on symptoms. You can see what others rated as most helpful there and try them to see if they work for you as well.