Intercorrelations among ADHD symptoms across the three time points were high (r values ranging from .69 to .81, all p values < .001), as were correlations among family climate (r values ranging from .43 to .59, all p values < .001), but they were small-to-moderate for school climate (r values ranging from .20 to .43, all p values < .001), for all variants of the DRD4 and 5-HTTLPR genotype. The gene discussed is DRD4; the disease is attention deficit-hyperactivity disorder.