Cannabis use: A co-existing condition in first-episode bipolar mania patients

An association between first-episode presentation of bipolar mania and concurrent cannabis use disorder has been well established in the current literature (Bally et al., 2014, Baethge et al., 2008). Previous studies have shown that 30-70% of patients admitted for a first manic episode had concurrent cannabis use (Bally et al., 2014). The exact mechanism of this association has yet to be confirmed.

We aim to evaluate the prevalence of cannabis use in patients with bipolar disorder (BD) admitted to UTHealth Harris County Psychiatric Center (HCPC) for a first manic episode.

In this retrospective cohort study, 15,969 inpatient records of patients admitted to HCPC between 2012-2013 were examined to identify patients admitted with a first manic episode according to ICD-9 criteria (single episode mania). The prevalence of multiple sociodemographic and clinical variables including cannabis positivity in urine drug screening (UDS) were examined.

Twenty patients were admitted for a first manic episode. Half of the patients were females; mean age was 28.65 ± 10.56 years and mean length of stay (LOS) was 7.15 ± 3.72 days. Fifteen patients received a UDS. Of these fifteen, seven were positive for cannabinoids (47%). One patient was positive for phencyclidine (in addition to cannabis) and one patient was positive for amphetamine (but not cannabis).

The prevalence of cannabis use was higher in first-episode mania patients compared to the general population. The influence of cannabis on the first episode of mania requires additional study.