A prescription THC drug put more than one-third of PTSD patients' nightmares into complete remission in a 10-week Charité trial

A 10-week, double-blind Phase II/III trial at Charité — Universitätsmedizin Berlin found that dronabinol, a prescription form of synthetic Δ9-THC, cut the frequency and intensity of PTSD-related nightmares by 1.5 points more than placebo on a standard clinical scale. More than one-third of patients on the drug saw their nightmares disappear completely by week 10, with more than half qualifying as responders, per the Charité summary.

Published this week in Nature Medicine, the study randomized 171 adults with trauma-related nightmares to once-daily dronabinol or placebo, dosed 2.5 to 15 mg before bed. The primary endpoint was CAPS-IV item B2, which scores nightmare frequency and intensity. The between-group difference was −1.50 points (95% CI −2.28 to −0.71), Cohen's d 0.65, P < 0.001. The trial was led by psychiatrist Stefan Röpke at Charité's Benjamin Franklin Campus.

No severe adverse events, withdrawal signals, or dependence emerged. The most common side effects were mild to moderate dizziness and headache. Dronabinol is prescribable in the US off-label, but Germany has no drug approved for trauma-related nightmares, and the 10-week window leaves durability open. The population skewed young (mean age 37.9) and female (79.3%). The trial was prospectively registered, per the protocol paper.