Clinical and social factors associated with attention-deficit hyperactivity disorder medication use: population-based longitudinal study.

BACKGROUND The impact of longitudinal psychiatric comorbidity, parenting and social characteristics on attention-deficit hyperactivity disorder (ADHD) medication use is still poorly understood. AIMS To assess the baseline and longitudinal influences of behavioural and environmental factors on ADHD medication use. METHOD Survival regressions with time-dependent covariates were used to model data from a population-based longitudinal birth cohort. The sample (n = 1920) was assessed from age 5 months to 10 years. Measures of children's psychiatric symptoms, parenting practices and social characteristics available at baseline and during follow-up were used to identify individual and family-level features associated with subsequent use of ADHD medication. RESULTS Use of ADHD medication ranged from 0.2 to 8.6% between ages 3.5 to 10 years. Hyperactivity-inattention was the strongest predictor of medication use (hazard ratio (HR) = 2.75, 95% CI 2.35-3.22). Among all social variables examined, low maternal education increased the likelihood of medication use (HR = 2.09, 95% CI 1.38-3.18) whereas immigrant status lowered this likelihood (HR = 0.40, 95% CI 0.17-0.92). CONCLUSIONS Beyond ADHD symptoms, the likelihood of receiving ADHD medication is predicted by social variables and not by psychiatric comorbidity or by parenting. This emphasises the need to improve global interventions by offering the same therapeutic opportunities (including medication) as those received by the rest of the population to some subgroups (i.e. immigrants) and by diminishing possible unnecessary prescriptions.