Age of Onset of Bipolar Disorder Linked With Substance Use Disorders

Time of onset of bipolar disorder has shown an association with incident substance use disorders, according to a study published in the Journal of Affective Disorders. Compared with those without bipolar disorder, substance use disorders are more prevalent in men with bipolar disorder when the onset of bipolar disorder occurred before age 60.

This cohort study included 38,173 men representative of their community who were aged 65 to 85 years at baseline. Of these, 175 individuals had bipolar disorder with onset before age 60 and 75 had an onset ≥ age 60. Alcohol use disorders were 3.87 times more common (95% CI, 2.52-5.93) in men with bipolar onset before age of 60 compared with healthy controls vs 2.38 times (95% CI, 1.08-5.25) in men whose onset was ≥ age 60. After adjustments, the hazard ratio for alcohol use among those with bipolar disorder whose onset came before age of 60 was 3.23 (95% CI, 1.87-5.58) and was 2.38 (95% CI, 1.38-4.11) for other substances. Those with bipolar disorder onset was ≥ age 60 showed no significant association with substance use disorders. Mortality hazard showed no correlation with the interaction between substance use and bipolar disorder.

The follow-up period for this study was 18 years. Researchers used the Western Australian Data Linkage System to identify substance use disorders and bipolar disorder among study participants. Data were also collected on comorbidities including hypertension, stroke, diabetes, and ischaemic heart disease. Of the study’s total sample, 707 (1.9%) were classified as having both alcohol and other substance use disorder, 1541 (4.0%) as having alcohol use disorder, and 6070 (15.9%) as having substance use disorder.

Researchers conclude that, “[substance] use disorders (alcohol or others) are more prevalent among older adults with than without [bipolar disorder], but new cases are only more frequent among men with [bipolar disorder] onset < 60 years of age. Grouping [bipolar disorder] into early and late onset is clinically informative and may affect approach to assessment and management.”

Reference

Almeida OP, Hankey GJ, Yeap BB, Golledge J, Flicker L. Substance use among older adults with bipolar disorder varies according to age at first treatment contact. J Affect Disord. 2018;239:269-273.