Nightmares can be one of the most exhausting symptoms of post-traumatic stress disorder, or PTSD.
For some people, sleep becomes a time when frightening memories return so vividly that they wake in panic and begin to fear going to bed.
PTSD can develop after experiences such as violence, war, serious accidents, disasters or other events that make a person feel that their life or safety is under threat. Symptoms can include unwanted memories, strong emotional reactions, avoiding reminders of the trauma and feeling constantly alert for danger.
Sleep problems are also common. Some people have trouble falling asleep, wake repeatedly during the night or experience recurring nightmares in which parts of the traumatic event seem to happen again.
These nightmares are more than ordinary bad dreams. Repeated sleep disruption can worsen daytime exhaustion, concentration, mood and the ability to cope with other PTSD symptoms.
Current treatments can help many people, especially trauma-focused psychological therapies. Medicines such as certain antidepressants are also used, while some doctors prescribe other drugs to target sleep or nightmares, but responses vary and many patients continue to struggle.
Researchers at Charité — Universitätsmedizin Berlin therefore tested whether Dronabinol, a prescription medicine containing tetrahydrocannabinol, or THC, could reduce severe PTSD-related nightmares. THC is best known as the main psychoactive compound in cannabis.
The idea is linked to the body’s endocannabinoid system. This signaling system helps regulate functions including stress, sleep and emotional processing, making it a possible target for problems that occur when traumatic memories intrude during sleep.
Researchers have been especially interested in rapid eye movement, or REM, sleep. This is the stage in which vivid dreaming is common and the brain is thought to process emotional experiences.
Professor Stefan Röpke and colleagues proposed that THC might reduce intense dream activity and the stress response connected with traumatic dreams. To test the idea properly, they conducted a randomized, double-blind and placebo-controlled clinical trial.
More than 170 adults with PTSD and frequent severe nightmares took part. For ten weeks, participants received either Dronabinol or a placebo designed to resemble the cannabis-based treatment.
The drops were taken in the evening before bedtime. Neither the participants nor the health professionals working directly with them knew who was receiving the active medicine, which helps reduce bias when symptoms are measured.
After ten weeks, nightmare severity had fallen more in the Dronabinol group. On an eight-point scale, the average score fell by 3.7 points among people receiving Dronabinol, compared with 2.2 points in the placebo group.
More than one-third of those treated with Dronabinol reported that their nightmares had disappeared by the end of the study. Another 21% said their nightmare burden had fallen by at least half.
About five out of six patients in the Dronabinol group also reported a noticeable improvement in their overall health. For people whose nights had been repeatedly disrupted by trauma, better sleep could potentially make daily life easier even if other PTSD symptoms remain.
That last point is important because the drug did not clearly improve every part of PTSD. Researchers could not conclusively show that Dronabinol reduced the overall severity of the disorder or accompanying depression.
This suggests the treatment may be more targeted toward sleep and nightmares rather than acting as a complete treatment for PTSD. Psychological therapies that address traumatic memories and avoidance would therefore remain important even if the drug is eventually used more widely.
The safety findings were encouraging over the ten-week period. No severe side effects were reported, although dizziness, headaches and increased appetite occurred more often among people receiving Dronabinol.
The researchers also did not observe withdrawal symptoms when treatment ended. However, the study was not long enough to answer every question about dependence, tolerance or the effects of using THC-based medicine for months or years.
That is one of the main limits of the research. Longer trials will be needed to see whether the benefits continue, whether patients need increasing doses over time and whether long-term treatment creates new risks.
The placebo group also improved substantially, which is common in studies involving symptoms such as sleep and distress. This means the real drug effect was meaningful but smaller than the improvement seen in the Dronabinol group alone might suggest.
Overall, the study provides stronger evidence than earlier reports because it used a large randomized and blinded design. Still, Dronabinol should not be viewed as a cure for PTSD, and the findings do not mean that ordinary cannabis use will produce the same effects or safety profile as a carefully dosed prescription medicine.
The research was published in Nature Medicine. If future studies confirm the results over longer periods, Dronabinol could become an additional option for people whose trauma-related nightmares continue despite standard treatment.
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Source: Charité — Universitätsmedizin Berlin.
