Cannabis use among people with schizophrenia was not linked to more hospitalizations or longer stays after adjusting for other factors

Among 517 hospitalized patients with schizophrenia or schizoaffective disorder, cannabis users had shorter hospital stays than non-users, but this difference disappeared after controlling for covariates.

Williams, Steven R et al.·Substance use & misuse·2021·Preliminary EvidenceRetrospective Cohort
RTHC-03616Retrospective CohortPreliminary Evidence2021RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Retrospective Cohort
Evidence
Preliminary Evidence
Sample
N=55

What This Study Found

Cannabis-only users (n=55) had shorter mean hospital stays than non-substance users (n=462): 6.15 vs. 8.66 days. However, this difference was no longer significant after controlling for covariates (p=0.15). The number of psychiatric admissions did not differ between groups.

Key Numbers

Cannabis users: 55. Non-users: 462. Mean LOS cannabis group: 6.15 days (SD 5.32). Mean LOS non-users: 8.66 days (SD 11.14). Mean admissions: 1.84. Unadjusted p=0.035; adjusted p=0.15.

How They Did This

Retrospective comparison of 55 cannabis-only users and 462 non-substance users hospitalized with a primary diagnosis of schizophrenia or schizoaffective disorder. Used Wilcoxon-Mann-Whitney tests, ANOVA, and Poisson regression with covariate adjustment.

Why This Research Matters

Contrary to common assumptions, cannabis use did not predict worse hospitalization outcomes in this population, suggesting the relationship between cannabis and schizophrenia course may be more nuanced than assumed.

The Bigger Picture

The finding that cannabis use did not worsen hospitalization metrics in schizophrenia challenges the assumption that cannabis universally worsens psychotic disorder outcomes.

What This Study Doesn't Tell Us

Small cannabis-only group (n=55). Retrospective design. Cannot account for cannabis potency, frequency, or timing relative to symptoms. Excluded polydrug users, limiting generalizability.

Questions This Raises

  • ?What covariates drove the loss of significance in adjusted models?
  • ?Does the type of cannabis (high-THC vs. balanced) matter for hospitalization outcomes in schizophrenia?

Trust & Context

Key Stat:
Cannabis use did not predict worse hospitalization outcomes after covariate adjustment
Evidence Grade:
Retrospective study with small cannabis group and limited covariate data.
Study Age:
Published in 2021.
Original Title:
Psychiatric Hospitalization and Length of Stay Differences in Cannabis Users and Non-Users with a Primary Discharge Diagnosis of Schizophrenia or Schizoaffective Disorder.
Published In:
Substance use & misuse, 56(11), 1736-1739 (2021)
Database ID:
RTHC-03616

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Looks back at existing records to find patterns.

What do these levels mean? →

Frequently Asked Questions

Does cannabis use lead to longer psychiatric hospital stays?

Not in this study. Cannabis users with schizophrenia actually had shorter stays initially, but the difference disappeared after controlling for other factors.

Did cannabis users get hospitalized more often?

No. The number of psychiatric admissions did not differ between cannabis users and non-users with schizophrenia.

Read More on RethinkTHC

Cite This Study

RTHC-03616·https://rethinkthc.com/research/RTHC-03616

APA

Williams, Steven R; Agapoff, James R; Jalan, Devesh; Hishinuma, Earl S; Kida, Lauren E. (2021). Psychiatric Hospitalization and Length of Stay Differences in Cannabis Users and Non-Users with a Primary Discharge Diagnosis of Schizophrenia or Schizoaffective Disorder.. Substance use & misuse, 56(11), 1736-1739. https://doi.org/10.1080/10826084.2021.1949615

MLA

Williams, Steven R, et al. "Psychiatric Hospitalization and Length of Stay Differences in Cannabis Users and Non-Users with a Primary Discharge Diagnosis of Schizophrenia or Schizoaffective Disorder.." Substance use & misuse, 2021. https://doi.org/10.1080/10826084.2021.1949615

RethinkTHC

RethinkTHC Research Database. "Psychiatric Hospitalization and Length of Stay Differences i..." RTHC-03616. Retrieved from https://rethinkthc.com/research/williams-2021-psychiatric-hospitalization-and-length

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.