Alcohol is toxic to the nervous system. The toxic effects can be acute or chronic. Acute alcohol intoxication can prevent the formation of new memories, leading people to not recall their actions (a “blackout”). Additionally, intoxication from alcohol puts a person at higher risk of an accident, which could result in traumatic brain injury. Alcohol withdrawal is also harmful to the brain, and withdrawal can be fatal if not managed correctly. Chronic alcohol misuse can lead to alcohol related cognitive impairment and alcohol related dementia.
Alcohol affects the brain in various ways:
- Alcohol accelerates brain aging, causing brain shrinkage out of proportion to the normal brain shrinkage that occurs with age. The cerebellum, a part of the brain responsible for coordination and balance, but also cognitive and sensory functions, is especially sensitive to alcohol, and its shrinkage is known as cerebellar degeneration. A person with cerebellar degeneration may experience tremor and unsteady gait.
- Alcohol accelerates atherosclerosis (hardening of the arteries) in the brain, which can lead to vascular dementia.
- Alcohol misuse can lead to problems with thiamine (vitamin B1) (its intake, absorption, and cell utilization), which is important for memory and normal brain function. Dementia caused by thiamine deficiency is called Korsakoff syndrome. People with Korsakoff syndrome are unable to form new memories, causing them to forget conversations from even just a few minutes prior.
- Alcohol misuse can cause liver disease, and since the liver filters toxins from the blood, liver damage can cause a buildup of toxins that harm the brain, a condition known as hepatic encephalopathy. In hepatic encephalopathy, a person may have confusion, decreased attention, slowness in thinking, muscle twitches (myoclonus and asterixis), mood changes, and drowsiness.
In a person with alcohol related cognitive impairment or dementia, abstinence from alcohol can improve cognitive symptoms and even the structural changes in the brain. A person and their caregivers may notice improved cognitive functioning after they stop drinking, though it could take even up to one year. A person with suspected alcohol related cognitive impairment or dementia may also have other causes for their symptoms, which may also be reversible. A comprehensive evaluation can clarify the various causes for a person’s cognitive dysfunction to ensure that all modifiable conditions that can improve brain health are addressed.
References and Resources
- Martin, PR, Singleton, CK, & Hiller-Sturmhofel, S. (2003). The role of thiamine deficiency in alcoholic brain disease. Alcohol Res Health, 27(2), 134-142.
- Kopera, M, Wojnar, M, Brower, K, Glass, J, Nowosad, I, Gmaj, B, & Szelenberger, W. (2012). Cognitive functions in abstinent alcohol-dependent patients. Alcohol, 46(7), 665-671. doi:10.1016/j.alcohol.2012.04.005
- Stavro, K, Pelletier, J, & Potvin, S. (2013). Widespread and sustained cognitive deficits in alcoholism: a meta-analysis. Addict Biol, 18(2), 203-213. doi:10.1111/j.1369-1600.2011.00418.x
- van Eijk, J, Demirakca, T, Frischknecht, U, Hermann, D, Mann, K, & Ende, G. (2013). Rapid partial regeneration of brain volume during the first 14 days of abstinence from alcohol. Alcohol Clin Exp Res, 37(1), 67-74. doi:10.1111/j.1530-0277.2012.01853.x
- Sachdeva, A, Chandra, M, Choudhary, M, Dayal, P, & Anand, KS. (2016). Alcohol-Related Dementia and Neurocognitive Impairment: A Review Study. Int J High Risk Behav Addict, 5(3), e27976. doi:10.5812/ijhrba.27976
- Ning, K, Zhao, L, Matloff, W, Sun, F, & Toga, AW. (2020). Association of relative brain age with tobacco smoking, alcohol consumption, and genetic variants. Sci Rep, 10(1), 10. doi:10.1038/s41598-019-56089-4