Assessing expectancy and suggestibility in a trial of escitalopram v. psilocybin for depression.
Balázs Szigeti, Brandon Weiss, Fernando E. Rosas, David Erritzøe, David Nutt, Robin Carhart-Harris
Psychological Medicine June 1, 2024 DOI: 10.1017/s0033291723003653 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Double-blind Peer reviewed |
|---|---|
| Sample size | 55 |
| Population | Adults with major depressive disorder |
| Interventions | Escitalopram COMP360 psilocybin |
| Topics | Depression Psilocybin |
| Keywords | Clinical trial Comparative effectiveness trial Expectancy Psychedelics psilocybin Hallucinogens Entheogens Antidepressants ssris Escitalopram Treatment expectations plac |
| Citations | 74 |
| Registration | NCT03429075 |
| Key findings | Pre-trial expectancy for escitalopram predicted response to escitalopram, but expectancy for psilocybin did not predict response to psilocybin; trait suggestibility predicted response to psilocybin but not escitalopram. |
Abstract
To investigate the association between pre-trial expectancy, suggestibility, and response to treatment in a trial of escitalopram and investigational drug, COMP360, psilocybin, in the treatment of major depressive disorder (ClinicalTrials.gov registration: NCT03429075). We used data (n = 55) from our recent double-blind, parallel-group, randomized head-to-head comparison trial of escitalopram and investigational drug, COMP360, psilocybin. Mixed linear models were used to investigate the association between pre-treatment efficacy-related expectations, as well as baseline trait suggestibility and absorption, and therapeutic response to both escitalopram and COMP360 psilocybin. Patients had significantly higher expectancy for psilocybin relative to escitalopram; however, expectancy for escitalopram was associated with improved therapeutic outcomes to escitalopram, expectancy for psilocybin was not predictive of response to psilocybin. Separately, we found that pre-treatment trait suggestibility was associated with therapeutic response in the psilocybin arm, but not in the escitalopram arm. Overall, our results suggest that psychedelic therapy may be less vulnerable to expectancy biases than previously suspected. The relationship between baseline trait suggestibility and response to psilocybin therapy implies that highly suggestible individuals may be primed for response to this treatment.
Comparable studies
Other randomized controlled trials on psilocybin for depression, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial Cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety | 2016 | Randomized controlled trial | n = 51 |
| Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial Patients with cancer-related anxiety and depression | 2016 | Double-blind, placebo-controlled, crossover trial | n = 29 |
| Trial of Psilocybin versus Escitalopram for Depression Selected group of patients with depression | 2021 | Randomized controlled trial | |
| Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder Adults aged 21 to 75 years with major depressive disorder, not currently using... | 2020 | Randomized controlled trial | n = 24 |
| Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression. Adults with treatment-resistant depression | 2022 | Phase 2 double-blind randomized controlled trial | n = 233 |