Hallucinogen-Psychosis Associations Are Confounded by Baseline Psychiatric History

Area of Science:

• Psychiatry and Public Health
• Substance Use Research
• Epidemiology

Background:

• Drug policy debates frequently question if hospital admissions linked to hallucinogen use imply a causal relationship with psychosis.
• This study investigates the role of pre-existing psychiatric conditions in mediating the association between hallucinogen use and psychosis.

Purpose of the Study:

• To examine the extent to which pre-existing psychiatric conditions mediate observed associations between hallucinogen use and psychosis.
• To provide evidence for informed psychedelic policy formulation.

Main Methods:

• Retrospective analysis of MarketScan Medicaid and commercial claims databases (2015-2019).
• Included individuals receiving substance use disorder treatment with substance-related emergency admissions or hospitalizations.
• Used Cox regression models to compare psychosis-related admissions between hallucinogen and nonhallucinogen substance users, adjusting for clinical characteristics and demographics.

Main Results:

• Psychosis diagnoses were more prevalent after hallucinogen-related admissions (16.4%) compared to nonhallucinogen substance admissions (6.6%).
• Unadjusted models showed an increased psychosis risk with hallucinogen use (HR=1.22), but this association became nonsignificant after adjusting for clinical factors (HR=0.97).

Conclusions:

• Observed associations between hallucinogen use and psychosis are primarily attributed to baseline psychiatric comorbidities, not direct causal effects.
• Findings suggest that population-level data on hallucinogen safety should consider underlying vulnerability factors.
• Results have implications for evidence-based policy development and regulatory frameworks concerning hallucinogens.