Dronabinol for nightmares in post-traumatic stress disorder: a randomized controlled trial.

Nightmares are a hallmark of post-traumatic stress disorder (PTSD), yet pharmacological treatments remain limited. Here we conducted a multicenter, double-blind, randomized, placebo-controlled trial to evaluate the efficacy and safety of dronabinol (BX-1; Δ9-tetrahydrocannabinol (THC)) for PTSD-related nightmares. Adults with PTSD and recurrent nightmares were randomly assigned to receive dronabinol (2.5-15 mg) or placebo, once daily before bedtime, for 10 weeks. The primary endpoint was change from baseline to week 10 in the Clinician-Administered PTSD Scale for DSM-IV (CAPS-IV) B2 item assessing nightmare frequency and intensity. A total of 171 patients underwent randomization (mean age, 37.9 ± 12.8 years; 79.3% female), with 87 assigned to dronabinol and 84 to placebo. At week 10, reduction in CAPS-IV B2 scores was significantly greater with dronabinol than with placebo (between-group difference -1.50; 95% confidence interval -2.28 to -0.71; Cohen's d = 0.65; P < 0.001). Adverse events occurred in 78 patients (89.7%) receiving dronabinol and 64 (77.1%) receiving placebo. Treatment discontinuation due to adverse events occurred in five (5.7%) and six (7.2%) patients, respectively. Serious adverse events occurred in seven patients (8.0%) receiving dronabinol and in none receiving placebo. This trial provides evidence that dronabinol reduces the frequency and intensity of PTSD-related nightmares, although long-term efficacy and safety require further evaluation. ClinicalTrials.gov: NCT04448808 .