Smoking may shrink the brain, study reveals
There had been numerous studies linking tobacco smoking to physical abnormalities in the brain but none had yet gone into examining the impact of smoking on the volume (thickness) of the brain tissue.
The researchers of the study published in the journal Biological Psychiatry particularly looked into the region of the brain called orbitofrontal cortex, a part of the cerebral cortex. The cerebral cortex is that convoluted mass of brain tissue seen at the outermost surface around the circumference of the brain. It is responsible for higher-order functions such as thought, perception, language, memory and attention.
Using high-resolution magnetic resonance imaging, the researchers compared the cortical thickness of 22 smokers against that of 21 never-smokers. Both groups had no medical or psychiatric illnesses. Results revealed that compared with never-smokers, smokers exhibited cortical thinning in the left medial orbitofrontal cortex. Thickness measures taken from that area of the cortex showed that thinning is worse with higher amount of cigarette consumption per day and greater lifetime exposure to tobacco smoke.
The orbitofrontal cortex is specifically involved in critical human functions defining personality, such as social adjustment, control of mood, drive and responsibility. Reduced cortical thickness has been seen in normal aging and associated with reduced intelligence and impaired cognition. Other recent imaging studies observed involvement of this brain region in mood disorders.*
The study further suggests that as the orbitofrontal cortex has been implicated in drug addiction, structural deficiencies within this area might be related to the drug-taking behavior seen in smokers. Lead author, Dr. Simone Kühn, explains that, “Since the brain region in which we found the smoking-associated thinning has been related to impulse control, reward processing and decision making, this might explain how nicotine addiction comes about.”
