Lack of sleep linked to decreased brain function

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Chronic insomnia may be associated with reduced cortical volume, says study

27. January 2010 05:39

Chronic and severely stressful situations, like those connected to depression

and posttraumatic stress disorder, have been associated with smaller volumes in

" stress sensitive " brain regions, such as the cingulate region of the cerebral

cortex and the hippocampus, a brain region involved in memory formation. A new

study, published by Elsevier in Biological Psychiatry, suggests that chronic

insomnia may be another condition associated with reduced cortical volume.

Using a specialized technique called voxel-based morphometry, Ellemarije Altena

and Ysbrand van der Werf from the research group of Eus van Someren evaluated

the brain volumes of persons with chronic insomnia who were otherwise

psychiatrically healthy, and compared them to healthy persons without sleep

problems. They found that insomnia patients had a smaller volume of gray matter

in the left orbitofrontal cortex, which was strongly correlated with their

subjective severity of insomnia.

" We show, for the first time, that insomnia patients have lower grey matter

density in brain regions involved in the evaluation of the pleasantness of

stimuli, as well as in regions related to the brain's 'resting state'. The more

severe the sleeping problems of insomniacs, the less grey matter density they

have in the region involved in pleasantness evaluation, which may also be

important for the recognition of optimal comfort to fall asleep, " explained

Altena. She added, " Our group previously showed that insomniacs have

difficulties with recognizing optimal comfort. These findings urge further

investigation into the definition of subtypes of insomnia and their causal

factors, for which we have now initiated the Netherlands Sleep Registry. "

Dr. Krystal, Editor of Biological Psychiatry, commented, that " insomnia is

a common feature of nearly every psychiatric condition associated with reduced

cortical volume; in fact, it is a common symptom of psychiatric disorders or

high levels of life stress, generally. The study by Altena and colleagues

suggests that there are additional risks of not treating insomnia, such as

detrimental effects on the microstructure of the brain. "

Source: Biological Psychiatry

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