Ten Weeks, Over 170 Participants
The study enrolled more than 170 people with diagnosed PTSD and frequent, intense nightmares. For ten weeks, participants received either dronabinol in drop form or a placebo each evening before bed. The placebo looked identical and tasted like cannabis as well. Neither the treating physicians nor the participants knew who received what treatment. This design meets the gold standard of clinical research: a double-blind, placebo-controlled trial.
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Initiated and led by researchers at the Charité Berlin, the study also involved the Psychiatric University Clinic at St. Hedwig Hospital, the University Hospital Hamburg-Eppendorf, and the Central Institute for Mental Health in Mannheim. The pharmaceutical company Bionorica SE provided support. Such investigations have been possible in Germany only since the „Cannabis as Medicine“ law took effect in 2017. The challenging path to this point is illustrated by the public hearing on the cannabis-as-medicine petition and the earlier debate between legalization and prohibition in medicine.
Nightmare Burden Decreased Nearly Twice as Much

Nightmare burden was measured on a scale of zero to eight points. In the dronabinol group, it decreased by an average of 3.7 points, compared to only 2.2 points under placebo. This is a difference that affected individuals notice clearly in daily life. Remarkably, the placebo itself showed strong effects—approximately one-third of the control group also responded.
More than one-third of patients treated with dronabinol reported experiencing no nightmares at all after ten weeks. A further 21 percent reported at least a 50 percent reduction in nightmare burden. Overall, roughly five out of six patients in the dronabinol group perceived their health status as significantly improved.
This quote comes from Prof. Stefan Röpke, who directs the trauma disorders research unit at the Clinic for Psychiatry and Psychotherapy at Campus Benjamin Franklin. For details on the specific preparation used, see our in-depth article on dronabinol as pure THC from the pharmacy.
Why REM Sleep Is the Focus

THC interacts with the body’s endocannabinoid system. This system is involved in regulating sleep, stress, and the processing of emotional memories. Researchers suspect this is where the mechanism of action occurs.
Evidence suggests that THC reduces trauma activity during REM sleep—the intense dream phases in which the brain processes experiences and regulates emotions—thereby alleviating nighttime stress reactions.
This explanation aligns with observations from earlier research. For an overview of the current evidence, see our analysis of what science really says about cannabis and sleep. A smaller 2022 study already showed that cannabis improves sleep in PTSD. What is new here is the scale and methodological rigor of the Berlin study.
What the Study Explicitly Does Not Show
The effect targeted nightmares and sleep specifically, not the disorder as a whole. The severity of post-traumatic stress disorder and accompanying depression did not change definitively. Dronabinol is therefore not a PTSD medication, but rather a treatment for one particularly distressing symptom.
Tolerability was favorable. Severe adverse effects did not occur. The team more frequently observed moderate and mild side effects such as dizziness, headaches, and increased appetite. Researchers found no withdrawal symptoms after stopping the evening doses. It remains unclear whether the effect persists beyond ten weeks or whether tolerance develops. This is exactly what the researchers intend to investigate next.
Filling a Real Gap in German Healthcare

Currently, no pharmaceutical preparation is approved in Germany specifically for trauma-related nightmares. Antidepressants and blood pressure medications are prescribed, but these typically do not address nighttime dream disturbances. For those interested in following the debate on cannabis in trauma therapy, our article on how veterans and trauma patients benefit from cannabis provides the broader context. The Berlin data now provides this discussion with the first robust randomized evidence from Germany. While this does not automatically lead to approval, it certainly strengthens arguments for cost coverage in individual cases.
Frequently Asked Questions
What is Dronabinol?
Dronabinol is prescription THC derived directly from the cannabis plant in this case. The study used it in drop form. In Germany, it is already prescribed in pain medicine, typically when standard treatments prove insufficient.
How many people participated in the study?
More than 170 patients with post-traumatic stress disorder and frequent, intense nightmares participated. They received either dronabinol or placebo each evening for ten weeks. Assignment was random and blinded.
Does THC cure post-traumatic stress disorder?
No. The effect was limited to nightmares and sleep. The severity of PTSD and accompanying depression did not change definitively in the study. Psychotherapy therefore cannot be replaced by this medication.
What side effects occurred?
There were no severe adverse effects. Participants more commonly reported dizziness, headaches, and increased appetite. After discontinuation, the research team found no withdrawal symptoms.
Can I get dronabinol prescribed for nightmares now?
There is no approved indication for this use in Germany. Prescription is theoretically possible on a case-by-case basis—the decision rests with the treating physician. The new data strengthens arguments with insurance companies but does not replace medical consultation.
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Sources: Charité, press release from 05.08.2026 „Cannabis active ingredient THC can eliminate trauma-related nightmares“; Roepke S et al., Dronabinol for nightmares in post-traumatic stress disorder: a randomized controlled trial, Nature Medicine, 05.08.2026, doi: 10.1038/s41591-026-04546-9; Deutsches Ärzteblatt, 05.08.2026.




































