In a retrospective study of 20 patients admitted for a first manic episode, 47% of those screened tested positive for cannabis on urine drug screening.
Psychiatrists, emergency medicine providers, and researchers studying bipolar disorder onset.
47% of screened first-episode mania patients tested positive for cannabis
What the researchers found
Of 15 patients who received urine drug screening, 7 (47%) tested positive for cannabinoids, a rate substantially higher than the general population. Only two patients tested positive for other substances.
Why it matters
The high prevalence of cannabis use among first-episode mania patients adds to evidence linking cannabis use to the onset of bipolar disorder, though the direction of this association remains unclear.
The numbers in context
20 patients identified from 15,969 records. 15 received UDS. 7 of 15 (47%) positive for cannabis. Mean age: 28.65 years. 50% female. Mean hospital stay: 7.15 days.
How the study worked
Retrospective cohort study examining 15,969 inpatient psychiatric records from 2012-2013 at a single center to identify patients admitted with a first manic episode (single episode mania per ICD-9 criteria).
What this study cannot tell us
Very small sample of 20 patients, making statistical analysis limited. Single center, retrospective design. Urine drug screening was not performed on all patients. The study cannot determine whether cannabis use preceded or followed mood symptoms.
How to read the evidence
Preliminary: very small retrospective sample (20 patients) from a single center.
When this study was published
Published in 2020 in Journal of Affective Disorders.
The bigger picture
The 47% cannabis positivity rate in first-episode mania is consistent with prior literature reporting 30-70% co-occurrence, raising questions about whether cannabis triggers mania in vulnerable individuals or whether both share common risk factors.
Questions still open
- Does cannabis trigger first manic episodes, or do people experiencing prodromal mania self-medicate with cannabis? Would routine cannabis screening in psychiatric emergencies improve diagnostic accuracy?
Common questions
Does cannabis cause bipolar mania?
How does 47% compare to the general population?
Read the original research
Cannabis use: A co-existing condition in first-episode bipolar mania patients.
Journal of affective disorders, 263, 289-291
Citation
Etyemez, Semra; Currie, Terrence T; Hamilton, Jane E; Weaver, Michael F; Findley, J Chase; Soares, Jair; Selek, Salih. (2020). Cannabis use: A co-existing condition in first-episode bipolar mania patients.. Journal of affective disorders, 263, 289-291. https://doi.org/10.1016/j.jad.2019.11.097
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