M-A: Psilocybin significantly reduces depression symptoms across diverse populations – The BMJ

Study Design and Population:

This systematic review and meta-analysis synthesized data from randomized trials assessing the efficacy of psilocybin as a treatment for depression in adults. Researchers utilized five electronic databases for published literature and four databases for unpublished and international studies. The analysis included 436 participants, aged 36 to 60 years, from seven randomized trials, with both genders represented and varying comorbidities such as cancer.

Main Findings:

The meta-analysis revealed a significant reduction in depression scores among participants treated with psilocybin, with a Hedges’ g value of 1.64, indicating a large effect size. Notably, the improvement was more pronounced among those with secondary depression and those assessed using self-report depression scales. Subgroup analyses and metaregression also highlighted that older age and previous use of psychedelics correlated with greater symptom improvement. Despite the robust findings, high heterogeneity and a risk of small study bias led to a low certainty of evidence.

Implications for Practice:

The findings support psilocybin’s potential as an effective antidepressant, particularly among specific subgroups such as those with secondary depression. However, the presence of high heterogeneity and small study biases suggests that further research is needed to explore the impact of expectancy effects, moderating factors, and treatment modalities. Clinicians should consider these elements when discussing psilocybin as a treatment option with patients, and further high-quality studies are necessary to solidify its role in clinical practice.

Reference (link to free full-text):

Reference: Metaxa, A.-M. et al. (2024). Efficacy of psilocybin for treating symptoms of depression: systematic review and meta-analysis. BMJ, 385. DOI: https://doi.org/10.1136/bmj-2023-078084.