Speech markers of psychological change following a psychedelic 5-MeO-DMT retreat

BACKGROUND: 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a potent, short-acting psychedelic, induces profound shifts in cognition, affect, and self-awareness. Because language explicitly expresses these domains and voice implicitly conveys them, both may serve as potential 'biomarkers' of behavioural change. AIM: This study introduces a novel framework for analysing baseline language and vocal features, pre- to post-psychedelic changes, and assessing their potential to predict subjective experiences and psychological outcomes. METHODS: Daily voice journals from 29 participants were collected via "RetreatBot" for 2 weeks before and after 5-MeO-DMT (1 × 12 mg). Transcripts were analysed using natural language processing (bag-of-words for vocabulary; transformer model for textual affect), and acoustic features (e.g. pitch, jitter, shimmer) were extracted to assess vocal dynamics. RESULTS: Following 5-MeO-DMT, speech markers revealed increased cognitive language, decreased social words, and altered voice quality (increased jitter/shimmer). Baseline speech patterns predicted psychedelic preparedness, emotional breakthrough, and post-experience well-being. CONCLUSION: This first longitudinal analysis of speech markers surrounding a psychedelic retreat reveals a shift from external focus to introspection. Speech markers predicted and tracked psychological transformation surrounding the 5-MeO-DMT retreat experience, establishing vocal journaling as a valuable framework for monitoring changes during the "preparation" and "integration" periods.