A recent follow-up study of a phase 2 clinical trial, published in eClinicalMedicine, has examined the long-term effects of psilocybin compared to escitalopram in patients with moderate-to-severe major depressive disorder (MDD). The study, presented at the European College of Neuropsychopharmacology (ECNP) Congress 2024, suggests that psilocybin demonstrates comparable efficacy to the conventional antidepressant escitalopram over a 6-month period.
Study Details and Findings
The double-blind, randomized, controlled trial initially compared the effects of psilocybin against escitalopram. The follow-up observational study aimed to assess the durability of these effects. While the authors attribute observed differences to the drugs themselves, potential biases in reporting due to participant preconceptions about psilocybin and unblinding during the follow-up phase should be considered.
Dr. James Rucker, Consultant Psychiatrist & Senior Clinical Lecturer in Psychopharmacology at King’s College London (KCL), noted, "The authors have tended to attribute differences observed in this study to comparative differences between the drugs themselves, however it is also possible that the results reflect biased reporting between groups. This is more likely here because A) studies involving psilocybin tend to attract those with positive preconceptions about psilocybin and negative preconceptions about conventional antidepressants, and B) study participants were unblinded during the long term follow up phase that is reported in the paper, so knew which condition they were allocated to."
Implications for Depression Treatment
Despite these limitations, the findings offer encouraging insights into alternative treatment options for depression. Given the heterogeneity of depression, a diverse range of treatment paradigms is necessary. Psilocybin therapy represents a distinct approach compared to traditional antidepressants like escitalopram.
"This said, the nature of depression varies hugely between individuals, and this calls for the development of a similarly varied suite of treatment paradigms. Psilocybin therapy is certainly a different paradigm of treatment to escitalopram. The observation of similar levels of effectiveness to antidepressants here is encouraging to see alongside the much larger trials of psilocybin currently underway here in the UK, Europe and the US," said Dr. Rucker.
Ongoing Research
Several larger trials are currently underway in the UK, Europe, and the US to further investigate the potential of psilocybin in treating depression. These studies aim to provide more definitive evidence regarding the efficacy and safety of psilocybin therapy.
