Cannabis-derived drug cuts PTSD nightmares in clinical trial

A prescription medication containing tetrahydrocannabinol (THC) significantly reduced trauma-related nightmares in people with post-traumatic stress disorder (PTSD), according to a study published in Nature Medicine. The research, led by scientists at Charité – Universitätsmedizin Berlin, tested dronabinol, a plant-derived THC formulation, against a matched placebo in a double-blind, placebo-controlled trial.

More than 170 adults diagnosed with PTSD and experiencing frequent, severe nightmares were randomly assigned to receive either dronabinol or a cannabis-flavored placebo as oral drops each evening for 10 weeks. Neither participants nor clinicians knew which treatment was administered until the study concluded.

Using an eight-point nightmare severity scale, patients treated with dronabinol showed an average reduction of 3.7 points compared with 2.2 points for the placebo group. Over one-third of participants receiving the active drug reported that their nightmares disappeared completely, while another 21 percent experienced at least a 50 percent reduction in severity.

Approximately five out of six patients taking dronabinol said their overall health had improved significantly during the treatment period. Lead researcher Prof. Stefan Röpke noted that targeting nightmares directly could provide meaningful relief even if other PTSD symptoms persist.

The study found that while dronabinol improved nightmare frequency and sleep quality, it did not conclusively reduce overall PTSD severity or accompanying depression. Researchers suggest that better sleep may still yield long-term benefits, as chronic sleep disruption worsens mental health and daily functioning in PTSD.

Side effects were mild to moderate and included dizziness, headaches, and increased appetite. No severe adverse events or withdrawal symptoms were reported after participants stopped the medication at the end of the 10-week period.

The authors emphasize that longer studies are needed to assess whether the treatment remains effective and safe with extended use and whether patients develop tolerance to THC over time. The trial involved collaborators from the Psychiatric University Clinic of Charité at St. Hedwig Hospital, the University Medical Center Hamburg-Eppendorf, and the Central Institute for Mental Health in Mannheim, with support from Bionorica SE.

Germany currently has no medications specifically approved for trauma-related nightmares, and existing therapies often provide limited relief. The findings suggest dronabinol could become a promising option for one of PTSD's most distressing symptoms.