In veterans, psilocybin's anxiety relief tracked entirely with depression improvement

Psilocybin's evidence base for treatment-resistant depression has grown substantially, but its effects on the conditions that commonly accompany depression — anxiety, disability, post-traumatic stress symptoms — have received comparatively less direct study, particularly in veterans, a population where these conditions frequently co-occur. A study published this month in the Journal of Affective Disorders reports exploratory findings on exactly this question from an open-label trial [s1].

The design

Fifteen veterans with treatment-resistant depression received a single 25 mg dose of psilocybin with psychological support [s1]. The primary assessment point was three weeks post-dose, with follow-up extending to 12 months; ten participants completed the long-term follow-up [s1]. Outcomes tracked included anxiety severity (GAD-7), quality of life (Q-LES-Q-SF), functional impairment (WSAS), and post-traumatic stress disorder symptoms (PCL-5) [s1]. Mixed-effects models evaluated changes over time, and correlation analyses tested whether these outcomes tracked alongside changes in depressive symptoms specifically [s1].

What it found

Anxiety scores showed sustained improvement through 12 months, with a 59% reduction from baseline at week 3 [s1]. Quality-of-life gains were significant through week 12, with a 24% increase at week 3 [s1]. Functional impairment improved through month 6 before declining, with a 46% reduction at week 3 [s1]. Unadjusted PTSD symptom scores were also reduced at all timepoints measured [s1].

But here's the finding that reframes all of the above: once the researchers accounted for concurrent improvements in depressive symptoms, the anxiety and functional improvements were "no longer statistically significant" [s1]. In other words, once depression itself improved, the anxiety and quality-of-life gains largely tracked alongside it rather than representing a separable, independent effect of psilocybin.

Why that adjustment is the study's most important methodological move

It would have been easy for this study to report anxiety, quality of life, and functioning improvements as independent findings and stop there — several of the raw, unadjusted numbers (a 59% anxiety reduction, a 46% functional impairment reduction) would make for a more dramatic headline in isolation. Instead, by explicitly testing whether these secondary improvements held up after accounting for depression change, the researchers distinguish between two very different possible interpretations: that psilocybin has broad, independent benefits across multiple domains, versus that psilocybin's primary effect is on depression, with anxiety and functioning improving as a downstream consequence of feeling less depressed rather than through a separate mechanism. Their own data supports the second, more conservative interpretation [s1].

What the acute-experience finding adds

The trial also measured acute subjective experiences during the dosing session itself — using the Mystical Experience Questionnaire, Challenging Experiences Questionnaire, and Emotional Breakthrough Inventory, tools commonly used across psychedelic research to characterize the drug session's phenomenology [s1]. Notably, these exploratory analyses found the acute subjective experience measures did not correlate with treatment response [s1] — meaning, in this small sample, having a more intense mystical experience or emotional breakthrough during the session wasn't associated with a bigger clinical improvement afterward, a finding that runs against a commonly proposed mechanism in psychedelic research linking the intensity or quality of the acute experience to therapeutic outcome.

What this doesn't establish

Fifteen participants, with only ten completing 12-month follow-up, is a small sample for parsing multiple secondary outcomes and their statistical relationship to a primary outcome — the kind of analysis that benefits from, and is more reliably interpreted with, considerably larger sample sizes. This was an open-label trial with no placebo comparison, meaning none of the reported improvements, adjusted or unadjusted, can be fully separated from expectation effects, natural symptom fluctuation, or the psychological support provided alongside dosing. The study's authors describe these as "exploratory findings" throughout [s1], appropriately calibrated language for a trial of this size and design.

What to watch

Whether larger, controlled trials confirm that psilocybin's benefits for anxiety and functioning in treatment-resistant depression are secondary to its antidepressant effect rather than independent, and whether the finding on acute experience intensity not predicting outcome replicates — a result with implications for how psychedelic-assisted therapy sessions are structured and evaluated going forward. Psilocybin is not approved for depression, anxiety, or PTSD; this article describes an early-stage investigational trial and is not medical advice.

Sources

1. Changes in anxiety, quality of life, and functioning following psilocybin-assisted therapy in veterans with treatment-resistant depression — Journal of Affective Disorders, 4 June 2026