Swiss Medical Society Shows 2-Year Anxiety Reduction After LSD Therapy

In Austin, Texas, at the Society of Biological Psychiatry (SOBP) meeting, SÄPT announced new data reflecting the long-term efficacy of LSD in treating anxiety. The data comes from the LSD-Assist Study, which evaluated the benefits and safety of LSD over an extended period among adults.

According to the findings presented, one year after the 50-week placebo-controlled phase of the study, remission rates for anxiety remained consistent, showing a slight increase from 32% at week 50 to 33% at week 102. This was measured using the State-Trait Anxiety Inventory-Global (STAI-G), a clinically validated tool.

Dr. Friederike Holze from University Hospital Basel, one of the study's presenters, highlighted the robust nature of the results. She noted that the reductions in STAI-G scores were statistically significant, rapid, and long-lasting. These results are promising, as they suggest sustained anxiety relief from LSD with a good safety profile. The study was meticulously designed as a randomized, double-blind, placebo-controlled clinical trial with a planned long-term follow-up.

During the 50-week placebo-controlled phase, the primary endpoint—reductions in STAI-G scores—was met. Specifically, LSD treatment led to significant reductions in anxiety 16 weeks after treatment, with the effects peaking two weeks post the second LSD session and persisting throughout the study. The least square mean change from baseline difference was -16.2 with a confidence interval ranging from -27.8 to -4.5, and the result was statistically significant (p=0.007).

Positive acute effects or mystical experiences during the LSD sessions were strongly correlated with long-term therapeutic outcomes at 16 weeks. Furthermore, LSD was generally well-tolerated, with only one serious adverse event (SAE) related to the treatment, which involved acute transient anxiety and delusions during an LSD session that resolved positively. Importantly, there were no instances of treatment-emergent suicidal ideation, behavior, or intentional self-injury.

The LSD-Assist Study was an investigator-initiated trial conducted across two centers. It employed a double-blind, placebo-controlled, cross-over design to assess LSD's safety and efficacy in treating anxiety. The trial included 46 patients with either anxiety symptoms related to life-threatening illnesses or anxiety disorders without severe somatic illness. Participants were randomly assigned to two sessions of either oral LSD (200 μg) or placebo, spaced six weeks apart, and were monitored for an initial period of 50 weeks.

The primary endpoint was anxiety symptom reduction 16 weeks post the second session, assessed via the STAI global score. Secondary outcomes included improvements in depression and other psychiatric symptoms, measured by tools such as the Hamilton Depression Scale (HAM-D-21) and the Beck Depression Index (BDI).

The long-term follow-up, planned from the study's inception, aimed to understand LSD's prolonged impact on anxiety. Participants were reassessed using the same validated questionnaires 52 weeks after their last visit from the placebo-controlled phase. The findings suggested enduring benefits from LSD treatment in alleviating anxiety, with improvements in STAI-G scores sustained 12 months post-study and no new adverse effects reported.

Dr. Peter Gasser, a co-investigator and President of SÄPT, expressed satisfaction with the results. He emphasized the importance of the study's long-term follow-up data in demonstrating the lasting efficacy of LSD treatment for anxiety.

The Swiss Medical Society for Psychedelic Treatment (SÄPT), founded in 1985, focuses on making psychoactive substances available for psychotherapeutic use, regulating their application, promoting research, and providing necessary training. The organization has been instrumental in pioneering psychedelic therapy, with Dr. Gasser leading it since 1997.