Two research reports in Nature have suggested links between smoking and impacts on brain thickness and plasticity, while a commentary in The Lancet Psychiatry discussed what the apparent strong links between smoking and schizophrenia may mean.
An international team including the Montreal Neurological Institute at McGill University and the University of Edinburgh studied 244 male and 260 female subjects, “five times larger than any previous similar research on smoking and cortical thickness,” stated a press release about one of the studies in Nature. “Their average age was 73. The test group included current smokers, ex-smokers and non-smokers. All of the subjects were examined as children in 1947 as part of the Scottish Mental Survey. Researchers used health data gathered during recent personal interviews with the subjects, and also analyzed data from MRI scans showing the current state of the subjects’ brain cortices.”
“We found that current and ex-smokers had, at age 73, many areas of thinner brain cortex than those that never smoked. Subjects who stopped smoking seem to partially recover their cortical thickness for each year without smoking,” the study’s lead author said in the press release.
“Although the cortex grows thinner with normal aging, the study found that smoking appears to accelerate the thinning process,” stated the press release, noting that impacts could endure for years after quitting smoking and were associated with dementia and cognitive loss.
A second study in Nature noted the fact that Transcranial Direct Current Stimulation seemed to induce impaired brain neuroplasticity in people with schizophrenia, and discovered that smoking seemed to resuscitate some of that neuroplasticity. “Our results provide first evidence for a smoking-induced restitution of impaired LTD-like neuroplasticity following cathodal tDCS in schizophrenia patients,” the researchers wrote. “Nonsmoking schizophrenia patients displayed abolished LTD-like plasticity compared with both smoking schizophrenia patients and respective healthy controls. In smoking schizophrenia patients, these plasticity deficits were not present. These findings implicate a beneficial effect of nicotine on impaired neuroplasticity in schizophrenia and may contribute to the excessive smoking rates in this population.”
Separately, a commentary in The Lancet Psychiatry reviewed evidence suggesting that smoking may be a risk factor for schizophrenia.
Smoking thins vital part of brain (McGill University press release on ScienceDaily, February 10, 2015)
Karama, S., S. Ducharme, J. Corley, F. Chouinard-Decorte, J. M. Starr, J. M. Wardlaw, M. E. Bastin, and I. J. Deary. “Cigarette Smoking and Thinning of the Brain’s Cortex.” Molecular Psychiatry, February 10, 2015. doi:10.1038/mp.2014.187. (Abstract and full text)
Strube, Wolfgang, Tilmann Bunse, Michael A. Nitsche, Thomas Wobrock, Richard Aborowa, Kristina Misewitsch, Maximiliane Herrmann, Peter Falkai, and Alkomiet Hasan. “Smoking Restores Impaired LTD-Like Plasticity in Schizophrenia: A Transcranial Direct Current Stimulation Study.” Neuropsychopharmacology 40, no. 4 (March 2015): 822–30. doi:10.1038/npp.2014.275. (Abstract and full text)
Gage, Suzanne H, and Marcus R Munafò. “Rethinking the Association between Smoking and Schizophrenia.” The Lancet Psychiatry 2, no. 2 (n.d.): 118–19. Accessed February 22, 2015. doi:10.1016/S2215-0366(14)00057-1. (Full text with free registration)