ADHD appears to be associated with depressed dopamine activity in the brain

Adults with attention-deficit/hyperactivity disorder (ADHD) show a blunted response to the drug methylphenidate (Ritalin), which increases brain dopamine levels, according to a report in the August issue of Archives of General Psychiatry, one of the JAMA/Archives journals. This suggests that dopamine dysfunction may be involved with ADHD symptoms and may contribute to substance abuse that often occurs simultaneously.