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Chemical Realities of ADHD Become Clearer
> 8/7/2007 9:33:36 AM

The neuro-chemical dopamine, an active agent in almost every mental illness, has been further implicated in facilitating the development of ADHD and the subsequent behaviors of those affected. Dopamine regulates emotional response and reward systems, and according to current studies, variations in the D4 receptor gene lead to decreased or depressed levels of dopamine in the brains of ADHD patients.

Researchers at the National Institute of Mental Health conducted a brain-scan study of 19 adults who'd been diagnosed with ADHD but never received treatment and 24 controls; their results seem to confirm not only the long-held belief that genetic dopamine tendencies play a major role in determining which individuals will eventually display ADHD but that depressed dopamine activity is the equation's major variable. In a separate study involving the MRIs of more than one hundred children with ADHD and approximately the same number without, researchers measured both neurological functions and anatomical trends in their subjects, noting not only the irregular dopamine levels encouraged by the polymorphic D4 gene but also a tendency toward smaller prefrontal cortex regions in ADHD children. The prefrontal cortex, like the chemical dopamine, is responsible for attention regulation as well as the cognitive appraisal of personal goals, rewards and the actions leading to them.

A greater propensity toward drug abuse has long been documented in ADHD patients, and the dopamine connection provides the most likely explanation. All drugs of abuse intensify the concentration of dopamine in the brain for varying periods after their consumption, and those with lower levels feel a more intense need for concentrated dopamine not only in order to get "high" but to balance the irregular functions of their brains. According to researchers in this study, ADHD patients may, by ingesting various intoxicants, "actually feel better and temporarily perform better." This finding also further illuminates the risks inherent in the stimulant nature of available ADHD medications which elevate dopamine levels in the brain much like illicit substances such as alcohol and cocaine. The chemical interactions engendered by intoxicants and stimulant medications heighten the potential for abuse (hence the recreational popularity of many ADHD drugs), and in this light the continued push toward non-stimulant medications is a major development whose positive implications could affect millions. An extended-release drug that operates by slowly bonding to related genes rather than amplifying dopamine concentration looks to be approved by the FDA in the next few weeks. Its success has yet to be demonstrated outside limited clinical studies, but its potential is enormous. Instead of a pathological need for immediate dopamine boosters, ADHD patients may be able to rely on a gradual, increasingly selective medication with less dramatic side-effects. As the drug gains popularity, it could also curb the prescription of its more narcotic predecessors. No one would suffer under that trend.

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