AbstractBackgroundADHD in childhood is associated with development of negative psychosocial and behavioural outcomes in adults. Yet, relatively little is known about which childhood and adulthood factors are predictive of these outcomes and could be targets for effective interventions. To date follow-up studies have largely used clinical samples from the United States with children ascertained at baseline using broad criteria for ADHD including all clinical subtypes or the use of DSM III criteria.AimsTo identify child and adult predictors of comorbid and psychosocial comorbid outcomes in ADHD in a UK sample of children with DSM-IV combined type ADHD.MethodOne hundred and eighteen adolescents and young adults diagnosed with DSM-IV combined type ADHD in childhood were followed for an average of 6 years. Comorbid mental health problems, drug and alcohol use and police contact were compared for those with persistent ADHD, sub-threshold ADHD and population norms taken from the Adult Psychiatric Morbidity Study 2007. Predictors included ADHD symptomology and gender.ResultsPersistent ADHD was associated with greater levels of anger, fatigue, sleep problems and anxiety compared to sub-threshold ADHD. Comorbid mental health problems were predicted by current symptoms of hyperactivity-impulsivity, but not by childhood ADHD severity. Both persistent and sub-threshold ADHD was associated with higher levels of drug use and police contact compared to population norms.ConclusionsYoung adults with a childhood diagnosis of ADHD showed increased rates of comorbid mental health problems, which were predicted by current levels of ADHD symptoms. This suggests the importance of the continuing treatment of ADHD throughout the transitional years and into adulthood. Drug use and police contact were more common in ADHD but were not predicted by ADHD severity in this sample.