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Currently, diagnoses of attention deficit hyperactivity disorder (ADHD) and hyperkinetic disorder (HKD) are made on the basis of phenomenology, but information is accumulating from the neurosciences about the biological bases of these disorders. Recent studies addressing the neuropsychology, neuroanatomy, neurochemistry, and molecular biology of ADHD/HKD(More)
CONTEXT Attention-deficit/hyperactivity disorder (ADHD)--characterized by symptoms of inattention and hyperactivity-impulsivity--is the most prevalent childhood psychiatric disorder that frequently persists into adulthood, and there is increasing evidence of reward-motivation deficits in this disorder. OBJECTIVE To evaluate biological bases that might(More)
Multiple theories of Attention-Deficit/Hyper-activity Disorder (ADHD) have been proposed, but one that has stood the test of time is the dopamine deficit theory. We review the narrow literature from recent brain imaging and molecular genetic studies that has improved our understanding of the role of dopamine in manifestation of symptoms of ADHD, performance(More)
When used to treat children with Attention Deficit Hyperactivity Disorder, methylphenidate (MPH) acts primarily by blocking the dopamine (DA) transporter (DAT) and increasing extracellular DA in the striatum. This is strikingly similar to the mechanism of action of cocaine, a primary stimulant drug of abuse. When administered intravenously, MPH like cocaine(More)
Dopamine is believed to play a major role in the manifestation of attention deficit hyperactivity disorder (ADHD), which affects 3-6% of school-age children and shows evidence of familiarity. The dopamine D4 receptor, which is preferentially distributed in cortical and limbic regions of the brain, is currently of major interest because of the high degree of(More)
Loss of control over drug taking is considered a hallmark of addiction and is critical in relapse. Dysfunction of frontal brain regions involved with inhibitory control may underlie this behavior. We evaluated whether addicted subjects when instructed to purposefully control their craving responses to drug-conditioned stimuli can inhibit limbic brain(More)
CONTEXT Attention-deficit/hyperactivity disorder (ADHD) is the most prevalent psychiatric disorder of childhood. There is considerable evidence that brain dopamine is involved in ADHD, but it is unclear whether dopamine activity is enhanced or depressed. OBJECTIVE To test the hypotheses that striatal dopamine activity is depressed in ADHD and that this(More)
The involvement of dopamine in drug reinforcement is well recognized but its role in drug addiction is much less clear. Imaging studies have shown that the reinforcing effects of drugs of abuse in humans are contingent upon large and fast increases in dopamine that mimic but exceed in the intensity and duration those induced by dopamine cell firing to(More)
Attention deficit hyperactivity disorder (ADHD) is the most frequent psychiatric disorder in children, yet data are sparse on its pathophysiology. Particularly relevant are the dopamine transporters since these are the main targets of stimulant medications used for ADHD treatment. Though some imaging studies have shown increases in dopamine transporters in(More)
Attention-Deficit/Hyperactivity Disorder (ADHD) has a very high heritability (0.8), suggesting that about 80% of phenotypic variance is due to genetic factors. We used the integration of statistical and functional approaches to discover a novel gene that contributes to ADHD. For our statistical approach, we started with a linkage study based on large(More)