Distinct Patterns of Intentional and Unintentional Overdose Among Psychiatric Patients With Bipolar and Substance Use Disorders.

BACKGROUND: Co-occurrence of Bipolar Disorder (BD) and Substance Use Disorder (SUD) increases the risk of negative mental health outcomes, including both intentional (i.e., suicide self-poisoning) and unintentional overdose (i.e., accidental). While it is clear that both forms of overdose are a relevant concern, less is understood about the differences in phenomenology between intentional and unintentional overdose among this high-risk group. METHODS: Demographic and clinical characteristics were drawn from a sample of patients at a Rhode Island hospital during their baseline session of a larger psychosocial intervention clinical trial. RESULTS: Among 171 participants with co-occurring BD-SUD, 77% reported a history of any type of overdose, 48% reported a history of unintentional overdose, 56% reported a lifetime suicide attempt via intentional overdose, and 28% reported experiencing both intentional and unintentional overdose. Collectively, antidepressant/antipsychotic/mood-stabilizing medications were the most frequently reported substances for intentional overdose, followed by sedating medications and alcohol. Opioids were the most frequently reported substance for accidental overdose, followed by alcohol and stimulants. Polysubstance use was indicated for 62% of intentional overdose events and 43% of accidental overdose events. Compared to participants with a history of intentional overdose only, those who have experienced both types of overdose were significantly younger and more likely to have co-occurring alcohol use disorder and drug use disorder. CONCLUSIONS: Our findings suggest that psychotropic medications traditionally used to treat BD and other psy- chiatric disorders are often implicated in intentional over- dose. Additionally, our results highlight the need for a focus on prevention of polysubstance overdose across the intentionality spectrum.