Neurocognitive predictors of substance use disorders and nicotine dependence in ADHD probands, their unaffected siblings, and controls: a 4‐year prospective follow‐up

Background Attention‐Deficit/Hyperactivity Disorder ( ADHD ) is a risk factor for substance use disorders ( SUD s) and nicotine dependence ( ND ). Neurocognitive deficits may predict the increased risk of developing SUD s and nicotine dependence. Methods This study comprised three groups derived from the Dutch part of the International Multicenter ADHD Genetics ( IMAGE ) study: ADHD probands ( n  =   294), unaffected siblings ( n  =   161), and controls ( n  =   214). At baseline (age = 12.2), a range of neurocognitive functions was assessed including executive functions (inhibition, working memory, timing), measures of motor functioning (motor timing and tracking) and IQ . After a mean follow‐up of 4.2 years, SUD s and ND were assessed. Results None of the neurocognitive functions predicted later SUD s or ND in ADHD probands, even after controlling for medication use and conduct disorder. Slower response inhibition predicted later nicotine dependence in unaffected siblings ( OR  = 2.06, 95% CI  = 1.22–3.48), and lower IQ predicted increased risk for SUD s in controls ( OR  = 1.96, 95% CI  = 1.12–3.44). Conclusions Cold executive functions, motor functioning, and IQ did not predict the elevated risk of SUD s and ND in ADHD . Future studies should target ‘hot’ executive functions such as reward processing as risk factors for SUD s or ND .