Post-traumatic stress disorder, or PTSD, can develop after people experience terrifying events such as war, assault, natural disasters or serious accidents.
Many people with PTSD repeatedly relive these events through distressing memories, flashbacks and especially nightmares. These nightmares can interrupt sleep night after night, leaving people exhausted, anxious and unable to recover emotionally.
Current treatments for PTSD include psychological therapy and medicines such as antidepressants. While these treatments help many patients, nightmares often continue even after other symptoms improve. Doctors have been searching for treatments that specifically target trauma-related nightmares.
A research team led by Professor Stefan Röpke at Charité–Universitätsmedizin Berlin investigated whether dronabinol, a prescription form of tetrahydrocannabinol (THC), could help.
THC is the main psychoactive compound found in cannabis and affects the body’s endocannabinoid system, which helps regulate sleep, stress and emotional memory. The findings were published in Nature Medicine.
Scientists believe THC may reduce dream activity during rapid eye movement, or REM, sleep. This is the stage of sleep when vivid dreaming usually occurs and when the brain processes emotional experiences. Reducing excessive dream activity may lessen trauma-related nightmares.
The clinical trial enrolled more than 170 adults with PTSD who experienced frequent severe nightmares. Participants were randomly assigned to receive either dronabinol drops or a placebo every evening for ten weeks. Neither the patients nor the researchers knew who received the real medicine until the study ended.
By the end of the trial, people taking dronabinol reported much greater improvement than those taking the placebo. Nightmare severity fell by an average of 3.7 points on an eight-point scale compared with 2.2 points in the placebo group.
More than one-third of patients taking dronabinol said their nightmares disappeared completely, while another one-fifth reported that their nightmares were reduced by at least half.
Most participants also felt their overall health had improved because they were finally able to sleep more peacefully. However, the medicine did not significantly improve every symptom of PTSD or reduce depression, suggesting that it may work best as part of a broader treatment plan rather than as a complete replacement for existing therapies.
The medicine was generally well tolerated. Some people experienced mild or moderate side effects such as dizziness, headache or increased appetite, but no serious safety problems were reported. Researchers also found no signs of withdrawal symptoms after treatment stopped.
The researchers now plan longer studies to determine whether the benefits continue over time and whether patients develop tolerance to the medicine. Study review and analysis: This randomized, double-blind, placebo-controlled trial provides strong evidence that dronabinol can reduce PTSD-related nightmares.
However, the study lasted only ten weeks, so long-term effectiveness and safety remain uncertain. The findings suggest the medicine could become an important option for patients whose nightmares do not respond to current treatments.
