New research shows the first definitive evidence that there is a chemical imbalance in the brains of those suffering from attention deficit and hyperactivity disorder (ADHD). The study, conducted by the US Department of Energy's (DOE) Brookhaven National Laboratory in New York State, has found that ADHD sufferers have deficiencies in the way the brain deals with dopamine, an amino acid involved in regulation of movement, thought, and behavior. "These deficits in the brain's reward system may help explain clinical symptoms of ADHD, including inattention and reduced motivation, as well as the propensity for complications such as drug abuse and obesity among ADHD patients,\u201d said Nora Volkow, lead author and director of the National Institute on Drug Abuse. During the study, brain scans were done on 53 adult ADHD patients who had never received treatment and 44 healthy control subjects. Study co-author Gene-Jack Wang, chair of Brookhaven's medical department, said: "Other studies from our group suggest that patients who abuse drugs or overeat may be unconsciously attempting to compensate for a deficient reward system by boosting their dopamine levels.\u201d "Understanding how deficits in the dopamine system contribute to ADHD and finding ways to improve the functioning of the reward system could help mitigate these troubling consequences in the ADHD patient population,\u201d he continued.