Study links primary insomnia to a neurochemical abnormality in young and middle-a...( Westchester Ill. A study in the Nov....),Health

Westchester, Ill. A study in the Nov. 1 issue of the journal Sleep is the first demonstration of a specific neurochemical abnormality in adults with primary insomnia, providing greater insight to the limited understanding of the condition's pathology.

Results indicate that gamma-aminobutyric acid (GABA), the most common inhibitory transmitter in the brain, is reduced by nearly 30 percent in individuals who have been suffering from primary insomnia for more than six months. These findings suggest that primary insomnia is a manifestation of a neurobiological state of hyperarousal, which is present during both waking and sleep at physiological and cognitive levels.

"GABA is reduced in the brain of individuals with insomnia, suggesting overactivity is present not only at the level of excessive thoughts and emotions, but can also be detected at the level of the nervous system," said principal investigator Dr. John Winkelman of Brigham and Women's Hospital, which is a teaching affiliate of Harvard Medical School in Boston, Mass.

GABA decreases overall activity in many brain areas, helping the brain to "shut down." Having a "racing mind" and an inability to shut down at night is a common complaint of people with primary insomnia.

Chronic insomnia, or symptoms that last for at least a month, affects about 10 percent of all adults in industrialized countries and is the most common sleep disorder. Most often insomnia is a "comorbid" disorder, present with another medical illness, mental disorder or sleep disorder, or associated with certain medications or substances. Approximately 25 percent of people suffering from insomnia are considered to have primary insomnia, which is defined as a difficulty falling asleep or maintaining sleep in the absence of coexisting conditions.

According to Winkelman, the recognition that primary insomnia is associated with a specific neurochemical deficiency helps validate the often
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