Is insomnia associated with grey matter in brain?

Severe and acutely stressful circumstances, like those associated with depression and post-traumatic stress disorder, appear to be linked to smaller volumes in ‘stress sensitive’ brain areas like the cingulate region of the cerebral cortex and the hippocampus, a brain area caught up in memory development. A new study proposes that insomnia could be a different condition related to decreased cortical volume.

By means of a particular method known as voxel-based morphometry, study authors supposedly assessed the brain volumes of people suffering from chronic insomnia who were otherwise mentally healthy, and apparently pitted them against fit people devoid of sleep issues.

Ellemarije Altena from the study team of Eus van Someren, commented, “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. 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. John Krystal, Editor of Biological Psychiatry, remarked, “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.”

The experts discovered that insomnia patients appeared to have a smaller volume of gray matter in the left orbitofrontal cortex, which was said to be powerfully connected to their subjective acuteness of insomnia.

The study was published by Elsevier in Biological Psychiatry.