Association of cannabis use with neurocognition in adolescents with bipolar disorder

Bipolar disorder (BD) and cannabis use are each associated with neurocognitive deficits in adolescents. However, little is known regarding the association of neurocognition with cannabis use among adolescents with BD. Therefore, we examined this topic in a sample of adolescents with BD and healthy control (HC) adolescents.

Participants included 121 adolescents (n = 32 with BD and lifetime cannabis use (BD_CB+), n = 31 with BD and no lifetime cannabis use (BD_CB-), n = 58 HC with no lifetime cannabis use), aged 14-20 years. Five neurocognitive subtests of the computerized CANTAB battery were assessed. Groups were compared using an analysis of covariance (ANCOVA) covarying for age, sex, and intelligence quotient.

The three groups differed significantly on tests of visuospatial working memory (F = 4.41, p = 0.014, $$) and sustained attention (F = 5.15, p = 0.007, $$). Post hoc analyses revealed working memory scores were significantly worse in BD_CB+ versus HC (p = 0.04, d = 0.59), and sustained attention was significantly worse in BD_CB- versus HC (p = 0.006, d = 0.70).

These preliminary findings suggest that cannabis use among adolescents with BD is associated with working memory deficits. Future studies in larger samples are warranted to evaluate causation versus predisposition to cannabis use, and to evaluate duration, quantity, and potency of cannabis on neurocognition among adolescents with BD.