2 Studies Tie Dopamine to ADHD
Low level of brain chemical connected to substance abuse, too
By Heather McPherson,  Newser User
Posted Aug 7, 2007 5:19 PM CDT

(Newser) – Levels of dopamine—a brain chemical associated with movement and emotion—may explain the occurrence of attention deficit and hyperactivity, two studies published yesterday concluded. The studies found decreased dopamine activity in the brains of individuals, both children and adults, diagnosed with ADHD. Doctors say these decreased levels could have an effect on cognition.

The studies might also explain why so many of those struggling with ADHD have problems with substance abuse. Drugs associated with addiction—alcohol, nicotine, meth, cocaine—temporarily increase the level of dopamine in the brain. The adult study involved comparing brain scans of adults with and without ADHD; the children's study compared MRI exams  of the two groups, as well as testing for a gene associated with low dopamine.