Sally Meikle is a PhD candidate specialising in behavioural psychopharmacology and psychedelic-assisted therapies. Completing her PhD through the University of Melbourne, her research focuses on the cognitive and social processing effects of classical psychedelics and the potential role of these effects in therapeutic contexts. She also served as the clinical trial coordinator for one of Australia’s first studies on psilocybin therapy for treatment-resistant depression, conducted in collaboration with researchers at Swinburne University. Sally’s broader interests include the ethical challenges of psychedelic therapies, aiming to inform responsible and equitable applications of these treatments in clinical settings.

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Twitter: @SallyEMeikle

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Psilocybin with Psychological Support for Treatment-Resistant Depression: A Pilot Clinical Trial

Amid growing interest in the therapeutic potential of psychedelics for treatment-resistant depression (TRD) and the recent rescheduling of psilocybin for this indication in Australia, this pilot open-label trial explores the safety, feasibility, and therapeutic impact of psilocybin combined with psychological support within an Australian context.
Seven participants completed the trial, which included two sessions of 25mg psilocybin spaced 4–6 weeks apart, along with three preparatory sessions and three integration sessions following each dose. Depression severity was assessed using the Quick Inventory of Depressive Symptomatology (QIDS). Acute subjective and expectancy effects were evaluated with various measures and qualitative interviews captured individual experiences. To understand the broader effects of psychedelic therapy, we evaluated cognitive and social processing through a comprehensive task battery, assessing processing speed, verbal fluency, learning and memory, executive function, cognitive flexibility, emotion identification, affect sharing, and self-other differentiation, alongside self-report assessments of broader socio-emotional functioning (pending analysis).
Consistent with previous research, we observed a substantial, clinically meaningful reduction in depressive symptoms at the primary endpoint (3-weeks post-dose 2; mean change = -7.14; Hedge’s g = 1.41; 95% CI [0.10, 2.71]), and the long-term follow-up (20-weeks post-dose 2; mean change = -7.14; Hedge’s g = 1.06; 95% CI [0.09, 2.22]). Looking at individual level data, two participants displayed a sustained treatment response, three showed a relapsing response, and two exhibited no substantial improvement. Exploratory analyses identified mindset prior to dosing, and spiritual experiences and perceptual shifts during dosing as possible predictors of treatment trajectory, while treatment expectations did not appear to influence treatment outcomes. These findings are further supported by initial analyses of qualitative interview data. Safety monitoring revealed adverse events largely consistent with previous studies with no serious adverse events, although some unexpected, related events were noted.
These findings underscore the potential of psilocybin therapy for TRD while highlighting the diversity of treatment responses. The individual-level presentation of data in this small study provides valuable insights into the interplay between individual differences, subjective experiences, and clinical outcomes, enhancing understanding of the complex dynamics in psychedelic therapy."