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SEEKING HYPERACTIVITY'S GENETIC ROOTS
Hyperactivity is a major risk factor for criminality and substance abuse (see related
article in Crime Times, Vol. 1, No. 3, Page 5),
and researchers suggest that early identification and treatment of
hyperactive children could greatly reduce the criminal population. Such identification
may soon become a reality, as researchers zero in on the genetic roots of hyperactivity.
Among recent studies:
-- Edwin Cook, Jr., and colleagues report an association between attention deficit
hyperactivity disorder (ADHD) and a variant of the dopamine transporter gene (DAT1).
The researchers investigated the gene because medications that affect hyperactive
children -- methylphenidate, amphetamines, etc. -- all work by inhibiting the dopamine
transporter (the mechanism by which dopamine is returned to the nerves that release
it).
If their findings are replicated, Cook et al. say, geneticists may be able to identify
hyperactive children early and begin treatment programs. In addition, they say,
identification of an association between DAT1 and hyperactivity "may lead to
development of more effective therapeutic interventions" and to the development of
better animal models for studying hyperactivity.
-- Joseph Biederman et al. recently studied the children of 31 adults diagnosed as
having ADHD. Of the 84 children they identified, 48 -- or 57 percent -- also met
diagnostic criteria for ADHD. This rate was much higher than the reported rate of
ADHD among siblings of hyperactive children, which is only about 15%.
Their findings, the researchers say, "suggest that childhood cases of ADHD that
continue through adolescence and adulthood have an especially strong familial
component." Thus, they say, researchers investigating the genetic roots of hyperactivity
should focus on families that include hyperactive adults.
The findings of Biederman et al. are of particular interest since hyperactive children
whose symptoms continue into adolescence and adulthood are much more likely to
become criminals than those whose symptoms of hyperactivity abate after childhood.
While genetic research may offer insights into hyperactivity, however, physicians stress
that attention deficit disorder and hyperactivity also can be caused by a number of non-
genetic factors. Neurologist Sydney Walker III notes that such diverse biological insults
as fetal alcohol syndrome, cardiac insufficiency, and lead toxicity can lead to
hyperactive behavior.
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"Association of attention deficit disorder and the dopamine transporter gene," Edwin
H. Cook, Jr., et al., American Journal of Human Genetics, 56, 1995. Address: Edwin H.
Cook, Jr., MC3077, 5841 South Maryland Avenue, Chicago, IL 60637.
--and--
"High risk for attention deficit hyperactivity disorder among children of parents with
childhood onset of the disorder: a pilot study," Joseph Biederman et al., American
Journal of Psychiatry, 152: 3, March 1995. Address: Joseph Biederman, Pediatric
Psychopharmacology Unit (WACC725), Massachusetts General Hospital, 15 Parkman
St., Boston, MA 02114.
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