This study is testing a medicine called **TSND-201** to see if it works and is safe for adults with **PTSD** (Post-Traumatic Stress Disorder). PTSD is a mental health condition triggered by a terrifying event. Participants will be randomly assigned to receive one of two doses of TSND-201 or a placebo (a "fake" treatment) once a week for 4 weeks. A placebo helps researchers see if the medicine really works. After the 4-week treatment, there will be an 8-week follow-up period to check on participants' health.
Participants must have PTSD symptoms for at least 6 months and have tried other treatments. They should be able to communicate well and not have any other serious illnesses. People with different primary psychiatric disorders or certain health issues, like heart problems, can't join. Participants need to avoid nicotine for 8 hours before each visit.
- Length of Study: Total of 12 weeks (4 weeks treatment + 8 weeks follow-up).
- Treatment Visits: Once a week for 4 weeks.
- Eligibility: Must have PTSD for at least 6 months and meet other health criteria.