Objective: To test whether the latent structure of attention deficit/hyperactivity disorder (ADHD) is best understood as categorical or dimensional in samples of 1774 children (aged 6-12 years) and 1222 adolescents (aged 13-17 years) drawn from an Australian epidemiological study.
Method: Two taxometric procedures (MAXEIG and MAMBAC) examined ADHD symptom measures assessed by diagnostic interview and parental ratings.
Results: Consistent with behavioural genetic research, findings fail to support the view that a latent category underpins ADHD.
Conclusions: ADHD is best modelled as a continuum among both children and adolescents, and no discrete dysfunction can therefore be assumed to cause it. The placement of the diagnostic threshold should therefore be decided on pragmatic grounds (e.g. impairment or need for treatment).