 ADHD is thought to be caused by an insufficiency of dopamine and norepinephrine activity in the prefrontal cortex of the brain.Most of the TCAs inhibit the reuptake of norepinephrine, though not dopamine, and as a result, they show some efficacy in remedying the disorder.Notably, the TCAs are more effective in treating the behavioral aspects of ADHD than the cognitive deficits, as they help limit hyperactivity and impulsivity, but have little to no benefits on attention.