Cannabis-using psychosis patients had more hospital readmissions and longer stays over 6 years
In a 6-year follow-up of 161 early psychosis patients, cannabis use at first admission predicted significantly more hospital readmissions and longer total hospital stays, especially in male and Black patients.
Quick Facts
What This Study Found
Researchers followed 161 patients admitted to an early psychosis intervention unit for 6 years, tracking hospital readmissions and total time spent hospitalized. Cannabis use was extremely common, with 62.4% reporting lifetime use at admission.
Cannabis use significantly predicted both the number of subsequent hospital readmissions and the total length of stay over the following 6 years. This relationship remained significant even after adjusting for use of other substances, indicating that cannabis had an independent effect on psychosis outcomes.
The impact was not evenly distributed across demographics. Male patients who used cannabis had particularly longer hospital stays compared to females. Black patients who used cannabis also had longer stays compared to other ethnic groups. These demographic disparities within the cannabis-using psychosis population highlight additional vulnerability factors.
The average patient had 2.2 readmissions over 6 years, spending a total of 197 days in the hospital, representing an enormous burden on both patients and healthcare systems.
Key Numbers
161 early psychosis patients. 62.4% had lifetime cannabis use. Average initial admission: 54.3 days. Over 6 years: 2.2 readmissions on average, 197.4 total hospital days. Cannabis predicted more readmissions and longer stays independent of other substance use. Male and Black patients most affected.
How They Did This
Retrospective cohort study of 161 consecutive early psychosis inpatients. Cannabis use at admission and hospital readmission data (number of readmissions and total length of stay) over a 6-year follow-up were extracted from clinical records. Analyses adjusted for use of other substances.
Why This Research Matters
Hospital readmission is one of the most concrete and costly outcomes in psychosis care. This study demonstrates that cannabis use at the first psychosis admission has lasting consequences for the disease trajectory, predicting worse outcomes for years to come. The economic implications are substantial.
The Bigger Picture
This study adds longitudinal evidence to the cannabis-psychosis literature, showing that the association extends well beyond the acute episode. The 6-year follow-up captures the chronic course of illness and demonstrates that cannabis use at the beginning of psychotic illness portends a more difficult trajectory.
What This Study Doesn't Tell Us
The retrospective design limits causal conclusions. Cannabis use was assessed at admission and may not reflect ongoing patterns. Readmission data does not capture outpatient functioning or community care. The study did not account for cannabis type, potency, or frequency. Racial disparities may reflect systemic healthcare factors rather than biological differences.
Questions This Raises
- ?Would cannabis cessation programs integrated into early psychosis intervention reduce readmission rates?
- ?Do the racial disparities reflect differences in cannabis use patterns, access to community support, or systemic healthcare inequities?
- ?Is cannabis a cause of worse outcomes or a marker of other risk factors?
Trust & Context
- Key Stat:
- Cannabis predicted more readmissions and 197 total hospital days over 6 years
- Evidence Grade:
- This is a retrospective cohort with 6-year follow-up, providing moderate evidence for the long-term impact of cannabis on psychosis outcomes.
- Study Age:
- Published in 2018. Cannabis intervention in early psychosis programs continues to be studied.
- Original Title:
- Longitudinal assessment of the effect of cannabis use on hospital readmission rates in early psychosis: A 6-year follow-up in an inpatient cohort.
- Published In:
- Psychiatry research, 268, 381-387 (2018)
- Authors:
- Colizzi, Marco(10), Burnett, Natoy, Costa, Rosalia, De Agostini, Mattia, Griffin, James, Bhattacharyya, Sagnik
- Database ID:
- RTHC-01624
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Does cannabis use lead to more psychiatric hospitalizations?
In this study, psychosis patients who used cannabis at their first admission had significantly more hospital readmissions and spent more total days hospitalized over the following 6 years, even after accounting for other substance use.
Does it matter who uses cannabis with psychosis?
The study found that male patients and Black patients who used cannabis had particularly longer hospital stays. This may reflect biological differences, social factors, differences in cannabis use patterns, or systemic healthcare disparities.
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Cite This Study
https://rethinkthc.com/research/RTHC-01624APA
Colizzi, Marco; Burnett, Natoy; Costa, Rosalia; De Agostini, Mattia; Griffin, James; Bhattacharyya, Sagnik. (2018). Longitudinal assessment of the effect of cannabis use on hospital readmission rates in early psychosis: A 6-year follow-up in an inpatient cohort.. Psychiatry research, 268, 381-387. https://doi.org/10.1016/j.psychres.2018.08.005
MLA
Colizzi, Marco, et al. "Longitudinal assessment of the effect of cannabis use on hospital readmission rates in early psychosis: A 6-year follow-up in an inpatient cohort.." Psychiatry research, 2018. https://doi.org/10.1016/j.psychres.2018.08.005
RethinkTHC
RethinkTHC Research Database. "Longitudinal assessment of the effect of cannabis use on hos..." RTHC-01624. Retrieved from https://rethinkthc.com/research/colizzi-2018-longitudinal-assessment-of-the
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.