How Does Alcohol Cause Brain Damage and Dementia?

Also known as alcohol-related brain injury, alcohol-related brain damage is a form of cognitive impairment that develops as a result of prolonged, heavy alcohol consumption, usually over many years. In some individuals, it manifests as only minor changes in thinking and memory known as mild cognitive impairment. Persons with this level of brain damage may develop symptoms such as:

• Trouble remembering important information, such as appointments
• Trouble with short-term memory
• Forgetting recent conversations
• Poor judgment or decision-making
• Difficulty remembering sequences of complex tasks
• Trouble processing visual information 

However, some individuals will develop more severe symptoms that are consistent with dementia, such as progressive memory loss, visual-spatial difficulties, problems managing simple tasks, and personality changes such as lack of interest, irritability, lack of empathy and aggression.

Unlike Alzheimer’s disease and other forms of dementia, alcohol-related brain damage is amenable to treatment as long as the afflicted person abstains from alcohol. 

Causes of ARBD

Alcohol-related brain damage is the result of alcohol’s toxic effects on the brain. These include the following:

• Damage to nerve cells: The brain is made up of billions of nerve cells, or neurons. Over time, excessive alcohol use can damage these cells, causing them to die and the brain to shrink. 
• Damage to blood vessels: Excessive alcohol consumption affects the ability of the blood vessels to expand and contract normally, causing decreased blood flow to the brain. It can also lead to high blood pressure and increased risk of stroke. 
• Thiamine deficiency: Thiamine (vitamin B1) is essential to the normal functioning of nerve cells in the brain. Chronic alcohol abuse causes decreased absorption of thiamine from foods and also impairs utilization of thiamine by the cells. Combined with poor nutrition, these factors cause thiamine deficiency, which leads to cell damage and cell death. In some people with severe thiamine deficiency, this ultimately causes acute brain inflammation (Wernicke’s encephalopathy) and a form of dementia known as Korsokov’s syndrome, which may be permanent. 

Research suggests that in most cases, these factors work together to cause alcohol-related brain damage.

Sources

“Alcohol-related brain damage (ARBD): what is it and who gets it?”. Alzheimer’s Society. https://www.alzheimers.org.uk/about-dementia/types-dementia/alcohol-related-brain-damage-arbd 

“Mild Cognitive Impairment (MCI)”. Alzheimer’s Association. https://www.alz.org/alzheimers-dementia/what-is-dementia/related_conditions/mild-cognitive-impairment 

“Wernicke–Korsakoff syndrome”. Alzheimer’s Society. https://www.alzheimers.org.uk/about-dementia/types-dementia/wernicke-korsakoff-syndrome 

“Alcohol-related dementia: an update of the evidence”. National Library of Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC3580328/