Stars and Stripes reports that a new study, which is about to begin accepting participants, will assess the safety and efficacy of four types of smoked marijuana to manage chronic, treatment-resistant post-traumatic stress disorder (PTSD) symptoms. In the first phase, 76 participants will smoke randomly assigned types of marijuana, including a placebo strain, from a pipe for three weeks. They will then abstain from smoking for two weeks. The second phase is a repeat of the first. Afterward, participants will follow up with the researchers for six months. The study should run about two years. Those interested in participating in the study in the Phoenix area can email firstname.lastname@example.org.