How Alcohol Causes Memory Loss

Alcohol can affect your memory short and long term. Consuming alcohol in large quantities can impair the ability to form new memories. This is referred to as an alcohol-induced blackout, which involves permanent memory loss that only affects you for the short period you were intoxicated.

Long-term, heavy use of alcohol can cause brain damage directly or indirectly. Brain damage from chronic alcohol use can result in an inability to form new memories and an impaired ability to retrieve existing memories.

How Does Alcohol Affect Memory? 

Alcohol can affect your memory in different ways. When you binge drink, the alcohol in your bloodstream can block or inhibit your ability to form new memories. There are two potential effects this can create:

• En-bloc amnesia: Also called a blackout, en-bloc amnesia occurs when alcohol completely blocks your memory for some time. Someone who has experienced a blackout will not be able to remember that period of time, no matter how hard they try.
• Fragmentary amnesia: Informally called a brownout, fragmentary amnesia will make the person who was drinking heavily only able to remember bits and pieces of what happened. They may be initially unable to remember anything but parts of it will return to them.

A more serious memory problem is Wernicke-Korsakoff syndrome, a condition caused by the effect of long-term alcohol use on thiamine (vitamin B1) levels. While initially treatable, this condition becomes permanent, causing gaps in your memory and an inability to form memories after the condition starts.

Signs of Alcohol-Induced Memory Loss

Alcohol intake, even in small amounts, harms cognitive functioning. The degree of memory impairment increases with the amount of alcohol intake. The more someone drinks, the more likely they will have a blackout period. Although individuals cannot remember events during the blackout, their short-term memories remain intact. This allows them to engage in conversations, drive a vehicle or perform other complex activities.

Some of the effects of an alcohol-induced blackout include:

• Inability to maintain a sustained focus on a conversation 
• Inability to remember events that happened minutes previously
• Long-term inability to remember what happened during the blackout

Although not always, chronic alcohol use may result in a permanent inability to form new memories. Some of the symptoms of long-term memory loss due to chronic alcohol intake include:

• Impaired ability to retrieve existing memories, along with an inability to form new memories
• Inability to recognize or identify objects despite intact sensory capabilities
• Impaired motor coordination
• Impairments in complex cognitive tasks involving planning and decision-making

Factors Contributing To Alcohol-Induced Memory Loss

Many factors can influence the extent of alcohol’s effects on an individual. Some of these factors include:

• Amount and frequency of alcohol intake
• Duration of alcohol intake and the person’s age when alcohol intake began
• Age and gender of the person
• Genetic background and history of alcohol misuse in the family
• General health influenced by lifestyle choices

Alcohol-Related Dementia

Wernicke-Korsakoff syndrome can cause alcohol-related dementia. Wernicke-Korsakoff syndrome happens when your thiamine (vitamin B1) levels are too low. Alcohol depletes thiamine levels and keeps your body from absorbing more thiamine correctly. Thiamine is essential to normal brain function. 

Wernicke-Korsakoff syndrome occurs in two stages. The first is Wernicke encephalopathy, in which the brain becomes inflamed due to the lack of thiamine. This condition is reversible if thiamine levels are replaced, but it is quite dangerous and can be fatal. Someone with Wernicke encephalopathy will have eye movement abnormalities, decreased coordination and confusion. Other neurological symptoms can also develop.

The second stage of this condition is Korsakoff syndrome. In this stage, the condition becomes permanent regardless of whether replacement thiamine is given or not. Korsakoff syndrome causes dementia in which new memories cannot be formed, and past memories are affected, causing gaps in memory. Someone with Korsakoff syndrome may have confabulations, memories made up by their subconscious to fill in gaps. Confabulations appear to be lies but are actually believed to be true by the person having them.

Prevention of Alcohol-Induced Memory Loss

One of the key ways to reduce the risk of memory loss is to restrict alcohol intake. Low levels of alcohol consumption can have protective effects on the brain. In fact, it is associated with a reduced risk of cognitive decline compared to abstinence or moderate to heavy use. The Office of Disease Prevention and Health Promotion recommends limiting alcohol use to moderate drinking, defined as two drinks per day for men and one for women.

Social drinkers may underestimate the risk of alcohol-induced blackouts, and research shows that blackouts are fairly common among social drinkers. Excessive alcohol intake in a short timeframe is the cause of alcohol-related  blackouts.

Ways to reduce your risk of having a blackout include:

• Having a meal before drinking
• Allowing sufficient time between
• Limiting drinks with high alcohol content

Alcohol Detox and Treatment

In addition to memory loss, prolonged use of alcohol in excessive amounts can lead to liver and cardiovascular problems. Long-term use of alcohol can also cause a physical alcohol dependence that may be severe enough to result in an addiction.

Treatment for alcohol dependence involves detoxification followed by different forms of therapy to prevent relapse. Stopping alcohol use can lead to withdrawal symptoms that range in severity. Symptoms appear about 6–24 hours after discontinuing alcohol use and may last 2–10 days. These symptoms tend to peak between 36–72 hours and include:

• Insomnia
• Nausea
• Vomiting
• Diarrhea
• Increased heart rate
• Anxiety
• Excessive sweating

More severe symptoms may include:

• Seizures
• Agitation
• Hallucinations
• Mental confusion 
• Fluctuations in blood pressure
• Delirium tremens

Treatment at a medical detox facility can help people cope with withdrawal symptoms, which can be particularly serious in cases of severe alcohol dependence. Treatment for alcohol dependence involves medications like naltrexone, which reduces cravings, or disulfiram, which interferes with the effects of alcohol intake.