Psilocybin-assisted therapy for veterans with treatment-resistant PTSD: a plain-language summary
A contributed article: the study's lead author summarises her own published research
Background
Post-traumatic stress disorder (PTSD) is a serious mental health condition that can develop after someone experiences or witnesses traumatic events. PTSD affects many military veterans, and some continue to have severe symptoms even after trying standard treatments like therapy or medication. For some, these treatments offer little relief. Because of this, researchers are looking for new ways to help people whose PTSD does not improve with current treatments.
What the study looked at
This study examined the safety, feasibility, and preliminary changes in PTSD symptoms of psilocybin-assisted therapy (PAT) in U.S. military veterans with severe PTSD that has not improved with other treatments. Psilocybin is a natural psychedelic compound that can produce significant changes in thoughts, feelings, and perception. In this study, psilocybin was given in a structured therapy setting, with preparation sessions before the doses of psilocybin and integration sessions after.
Who took part
The study was conducted at The Ohio State University Center for Psychedelic Drug Research and Education. The participants were veterans between 21 and 64 years old who had been diagnosed with PTSD for at least six months and who had not improved after therapy and antidepressant treatment. Twelve veterans completed the study.
How the treatment worked
The intervention lasted about 11 weeks. Before getting psilocybin, participants attended four preparation sessions, which totaled about eight hours of therapy. They then had two psilocybin sessions, spaced two to three weeks apart. The first session used a 15 mg dose of synthetic psilocybin, and the second used 25 mg. On dosing days, trained facilitators supported participants in a comfortable clinic setting. After each session, participants attended integration sessions to help them reflect on and understand their experiences. Researchers checked PTSD symptoms, side effects, and suicidal thoughts or behaviors regularly during the intervention and for one month after the last psilocybin session.
Safety
The main goal of the study was to see if the treatment was safe. No serious side effects occurred. The most common side effects were headaches, anxiety, and dizziness, but these were usually mild or moderate and temporary. During the dosing sessions, researchers also monitored heart rate and blood pressure, which stayed within safe limits. Suicidal thoughts and behaviors did not increase during the study.
Changes in PTSD symptoms
Researchers also monitored how PTSD symptoms changed. They measured PTSD severity with clinician-rated assessments and self-report questionnaires. On average, participants had much lower PTSD symptoms from before treatment to one month after the second psilocybin session. Nine out of twelve participants (75%) had at least a 50% drop in clinician-rated PTSD symptoms and met the study’s criteria for remission, meaning their symptoms were below the level used to determine PTSD in the trial. Ten participants (83%) had what researchers called a meaningful improvement in symptoms.
Why symptoms may have improved
The study also looked at why symptoms might have improved. Some participants’ symptoms started to improve by the end of the preparation phase and before receiving psilocybin, and those veterans tended to have better PTSD symptom scores one month later, which may suggest that the therapy sessions and relationship with therapists may have been important. Participants’ expectations about the treatment did not seem to explain the improvements.
Limitations
While these results are promising, there are some important limitations to keep in mind. This was a small study with only 12 participants. There was no control group, so researchers could not compare the results with another treatment or a placebo. The study was open-label, so both participants and researchers knew psilocybin was being given. Researchers followed participants for only one month after treatment, so we do not know the long-term effects. Also, because the study excluded people with certain medical or psychiatric conditions, the results may not apply to all veterans with PTSD.
Summary
In summary, these results suggest that psilocybin-assisted therapy can be safely given to veterans with severe, treatment-resistant PTSD in a supervised clinical setting. Most participants had meaningful reductions in PTSD symptoms, and no serious safety problems were found. However, these findings are preliminary. Larger, randomized, controlled studies are needed to find out if psilocybin-assisted therapy works, how long the benefits last, and who is most likely to benefit.