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Background Results
Psilocybin-assisted psychotherapy for the treatment of Major Depressive Disorder:
Preliminary results from a randomized controlled trial
Major Depressive Disorder (MDD) is a prevalent condition that
confers substantial public health burden. Current approved
treatments, including pharmacotherapy and psychotherapy, are
limited in effectiveness and adherence. Recent evidence suggests
that one or two administrations of psilocybin under psychologically
supported conditions produces antidepressant effects in cancer
and treatment-resistant depression populations.
Aims and Method
This is a randomized waitlist control trial investigating the immediate
and enduring antidepressant effects of two psilocybin administration
sessions (20mg/70kg and 30mg/70kg) given in the context of
psychotherapy in patients diagnosed with MDD.
Outcome measures include the GRID-Hamilton Depression Rating
Scale (GRID-HAMD) scores at Baseline (>17 required for
enrollment) and 1-and 4-weeks after the second psilocybin
session.
As of December 2018, a total of 12 participants completed the
intervention and the 1- and 4-week assessments:
※Mean age = 39, SD = 14
※Female = 67%
※Mean Years with depression = 16.8, SD = 13.7
Conclusions
Alan K. Davis PhD, Darrick G. May MD, Mary Cosimano MSW,
Matthew W. Johnson PhD, Frederick S. Barrett PhD, Roland R. Griffiths PhD
Johns Hopkins University School of Medicine, Department of Psychiatry and Behavioral Sciences, Psychedelic Research Unit
These preliminary data extend previous studies in depressed cancer patients and patients with treatment-resistant depression by
suggesting that psilocybin-assisted psychotherapy may be efficacious for treatment of MDD in the general population. The overall effect of
this intervention across conditions is 3-4 times above the threshold considered a “large” effect (>0.80). Furthermore, the trend of changes in
depression scores by condition suggests that these effects are not accounted for by the passage of time. Future analyses of a larger patient
sample will include statistical comparison of waitlist and immediate treatment conditions as well as assessment at long-term follow-up time
points at 3, 6, and 12-months.
*** p<.001; ^^^ Effect size: Cohen’s d = 2.7; +++ Effect size: Cohen’s d = 3.1
Funding
The study was supported by a crowdsourced funding campaign organized by Tim Ferriss and by a grant from the Riverstyx Foundation.
Dr. Davis and Dr. May were supported by a NIDA T32 postdoctoral training grant (#DA007209). Drs. Griffiths and Johnson were supported
by a NIDA grant (R01DA003889). The funding sources had no role in the design/execution of this study or the interpretation or
communication of findings.
Contact email for corresponding author: alan.kooi.davis@gmail.com
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Change in mean depression score
from Baseline to 1-wk
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Change in mean depression score
from Baseline to 4-wk
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Mean GRID-HAMD scores: Baseline = 22.8 (SD = 3.1), 1-wk = 8.3 (SD = 6.9), 4-wks = 8.0 (SD = 5.9)
For primary statistical analysis we combined Baseline and 1- and 4-
week follow-up data from the waitlist and immediate treatment
groups to examine overall treatment effect of the psilocybin
intervention. We combined groups because only 3 participants had
completed the waitlist condition at time of analysis.
We calculated the reduction in depression scores (% decrease) at
1-wk and 4-wks, the proportion of participants with a clinically
significant response (>50% decrease in GRID-HAMD scores) at 1-
wk and 4-wks, and the proportion of participants meeting criteria for
remission (<7 on the GRID-HAMD) at 1-wk and 4-wks. Additionally,
we used a paired samples t-test to compare mean depression
scores from baseline to 1-wk and 4-wks.
Lastly, we plotted mean GRID-HAMD scores at all time points in
two separate figures (bottom of results), one for each condition, to
present trend data for the treatment effect.
Data Analyses
Baseline 1-wk Baseline 4-wks
Change in depression scores over time
as a function of treatment condition
83%83%
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1-wk 4-wks
Proportion of participants meeting criteria for
clinically significant response (>50% decrease
in depressions scores)
at 1-wk and 4-wks
58%58%
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1-wk 4-wks
Proportion of participants meeting criteria
for remission (>7 on GRID-HAMD)
at 1-wk and 4-wks