New Johns Hopkins Psilocybin Study Explores Long-term Effects on Major Depressive Disorder

Medically reviewed by 
Mindbloom Review Board
Published on 
March 7, 2022
Updated on 

In recent years, studies have suggested that psilocybin, the psychedelic compound in certain mushrooms, has the potential to quickly help those challenge with mental health conditions like major depressive disorder (MDD), though it wasn’t clear for how long. Now, a follow-up study into psilocybin treatment for MDD suggests that impact could last longer for some patients —up to one year.

A new study from researchers at Johns Hopkins University School of Medicine (Johns Hopkins)  examines how long the effects of psilocybin, combined with talk therapy, can last.

Psilocybin, combined with psychotherapy, shows antidepressant effects

Preliminary data had suggested that psilocybin-assisted treatment led to quick and significant antidepressant effects in patients with MDD, though it was unclear how long those effects could last. The new study, published in the The Journal of Psychopharmacology, examined the efficacy and safety of psilocybin-assisted therapy through a 12-month period.

The study analyzed participants who had experienced depression long-term, the majority of whom having experienced depressive symptoms for about two years before the start of the evaluation. The participants included 19 women and five men, with the average age of 40. The majority of participants —88%— had previously been taking standard antidepressants, with 58% who reported using antidepressants to treat their current depressive episodes.

Once screened, the study’s participants were randomly assigned into one of two groups: those receiving treatment right away, and those receiving treatment after an eight-week stretch. Once it was time for treatment, the participants all went to six to eight hours of preliminary meetings with two treatment facilitators. 

Following this, the study’s participants were given two doses of psilocybin, approximately two weeks apart. They returned to the follow-up a day and a week after each session, followed by one, three, six and 12 months after the second session. Though 27 participants had been recruited for the study, by the end, 24 of the research participants had finished both the psilocybin session and the follow-up assessment appointments. 

Psilocybin meaningfully reduced depression symptoms based on rating scale

Researchers found that the psilocybin treatment in both groups led to a considerable dip in depression, and the severity of the mental illness stayed low one, three, six and 12 months after treatment was completed. The GRID-Hamilton Depression Rating Scale was used to measure depressive symptoms prior to treatment, as well as after. This standard tool to assess depression uses a score system, in which 24 or higher means severe depression, 17-23 moderate, 8-16 mild and 7 or less no depression.

For most participants in the study, scores went from 22.8 at pretreatment to 8.7 after one week, 8.9 after four, 9.3 at three months, 7 at six months and 7.7 at one year after treatment.

"Psilocybin not only produces significant and immediate effects, it also has a long duration, which suggests that it may be a uniquely useful new treatment for depression," Roland Griffiths, PhD, one of the study’s authors and founding director of the Center for Psychedelic and Consciousness Research at Johns Hopkins, said in a statement to Science Daily

Natalie Gukasyan, MD, another author of the study, cautioned that “the results we see are in a research setting and require quite a lot of preparation and structured support from trained clinicians and therapists, and people should not attempt to try it on their own.”

The study notes that further research is needed with active treatment or placebo comparison controls, involving larger and more diverse populations to examine if the effects of psilocybin-related treatment has the potential to last longer than 12 months.



This article is for informational purposes only and is not intended to be a substitute for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. If you are in a life-threatening situation, call the National Suicide Prevention Line at +1 (800) 273-8255, call 911, or go to the nearest emergency room.

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