The National Institute on Alcohol Abuse and Alcoholism (NIAAA) reports that more than 85 percent of all American adults (18 and older) had consumed alcohol at some point in their lifetime as of 2014.
Alcohol is rapidly absorbed into the bloodstream and carried into the brain where it acts on some of the levels of its chemical messengers, or neurotransmitters, including:
- Dopamine: helps to regulate emotions and enhance pleasure
- Serotonin: acts as a mood stabilizer and helps to regulate healthy sleep
- GABA (gamma-aminobutyric acid): suppresses functions of the central nervous system and reduces the stress response
- Glutamate: related to memory functions and formation
Alcohol increases the levels of dopamine, serotonin, and GABA in the brain while inhibiting the normal transmission of glutamate. High levels of dopamine and serotonin serve to make individuals feel happy, less inhibited, and more social. When high levels of GABA are present, relaxation results.
Alcohol interferes with brain chemistry, which in turn can affect brain circuitry and structure. The National Institute on Drug Abuse (NIDA) warns that alcohol consumption can damage the hippocampus, which is involved in memory functions and learning abilities; the cerebral cortex, which is responsible for decision-making skills and problem-solving abilities; and the cerebellum that works with coordination, emotional regulation, and movement capabilities.
With repeated abuse, alcohol can actually create physical changes in brain structure, impacting cognitive functions and behaviors, that may only be partially reversible.
How Alcohol Impairs Cognitive Abilities
Cognition refers to the ability to acquire, process, store, and retrieve information. Alcohol impairs cognitive behaviors in a variety of ways. Individuals under the influence of alcohol may take bigger risks, experience short-term memory loss (or “blackouts” where are unable to remember things from a certain period of time), make poor decisions, and be unable to think clearly. Alcohol impairs coordination, executive learning functions, reflexes, and the ability to properly discern and react to danger. It also impedes complex thought patterns on a short-term basis.
Alcohol impacts visuospatial abilities, which is the perception of objects and their spatial relationship. Putting things together and forming complex patterns may then become difficult while under the influence of alcohol. Motor skills, hand-eye coordination, and the ability to process information properly are also negatively affected by alcohol abuse. Higher cognitive functioning, which includes abstract thinking, the ability to construct and implement a plan, and the ability to make changes to a plan when necessary, is impaired due to alcohol intoxication.
Alcohol intoxication occurs when someone raises their blood alcohol concentration (BAC). When alcohol is consumed, it is metabolized and filtered out via the liver. Depending on several factors, such as weight, gender, ethnicity, genetic factors, the amount of food in the system, other drugs or medications taken, and the rate of consumption, alcohol is metabolized, and intoxication may occur, at different rates. In general, the higher the BAC, the more impaired a person becomes.
The amount of alcohol contained in one drink may not be the same depending on the type of beverage consumed. Typically, a standard drink , as defined by the Dietary Guidelines for Americans, is as follows:
- One 12-ounce beer or malt beverage containing 5 percent alcohol
- One 5-ounce glass of wine containing 12 percent alcohol
- A 1.5-ounce shot of distilled spirits containing 40 percent alcohol
- Any drink containing 0.6 fluid ounces of pure alcohol
Alcohol may have the following effects, as published by the Centers for Disease Control and Prevention (CDC):
Driving while intoxicated is highly dangerous, as cognitive functions are significantly impaired. In all 50 states, the legal BAC level for driving is below 0.08 percent, according to the DMV (Department of Motor Vehicles).
The CDC publishes that almost 10,000 people died in a crash involving an alcohol-impaired driver in 2014.
According to NIAAA, regular and prolonged alcohol abuse can shrink the brain’s mass over time and cause a variety of negative cognitive effects. Short-term memory and learning functions may be affected.
Individuals who engage in chronic excessive or binge drinking episodes, that is they regularly raise their BAC to 0.08 g/dL or higher, are more prone to the negative effects of alcohol. Drinking more than three drinks a day or seven in a week for a woman, and four in a day or 14 in a week for a man, can be a risk factor for developing an alcohol use disorder (AUD), NIAAA warns. Addiction involving alcohol is considered a brain disease, as the brain’s wiring and circuitry are altered and the ability to control drinking is impeded. An individual may be able to think of little else other than alcohol and the next drink.
Drinking alcohol at a young age, such as before age 14, can more than quadruple the risk for developing an alcohol dependency after age 18, the National Survey on Drug Use and Health (NSDUH) of 2013 warns. Alcohol negatively impacts parts of the brain that are underdeveloped in adolescents and young adults, leading to memory and learning issues, difficulties controlling impulses, impaired decision-making abilities, and mood regulation issues.
Regular alcohol use can cause the brain to become dependent on alcohol, requiring its presence in order to keep moods and some physical attributes stabilized. Since GABA is increased with alcohol consumption and serves to slow functions of the central nervous system, if alcohol is suddenly removed after a dependence has formed, these autonomic functions can rebound. This occurs as the brain struggles to restore balance to its chemical makeup. Heart rate, blood pressure, body temperature, respiration, and the stress response are then heightened.
During alcohol withdrawal, concentration levels, thought processes, and memory functions may be impaired. Individuals may suffer from “foggy thinking” as well as depressed moods, insomnia, and anxiety.
About 3-5 percent of the time, alcohol withdrawal is severe and leads to delirium tremens (DTs), which can cause hallucinations, seizures, and significant confusion. It is potentially life-threatening, the New England Journal of Medicine (NEJM) publishes. Due to the potential significance of alcohol withdrawal, consumption should never be stopped “cold turkey” once dependence has developed. Medical detox is always required.
The Oxford Journal postulates that alcohol is a causal factor in 10-24 percent of all dementia cases. Dementia is a serious brain condition that causes significant decline in memory and mental abilities that can make it difficult for a person to perform daily life tasks.
When someone drinks alcohol regularly for a long time, such as in large amounts for several years, it can cause a severe depletion of vitamin B1, or thiamine. This can lead to Wernicke’s encephalopathy, which causes mental confusion, visual problems like double vision and/or nystagmus (involuntary eye movements), and ataxia (lack of muscle control). It can be fatal without treatment. Wernicke’s encephalopathy can be successfully treated and its negative effects can be potentially reversed with complete alcohol abstinence. Around 85 percent of the time, however, the Oxford Journal reports that Wernicke’s encephalopathy develops into Korsakoff syndrome, an irreversible and severe form of alcohol-related dementia.
Korsakoff syndrome impedes a person’s ability to function in daily life without help, as it impairs the formation of new memories and the ability to learn new information, and may cause gaps in long-term memories. Someone suffering from Korsakoff syndrome may hallucinate or make up stories to fill in their memory lapses (called confabulation). They may believe that these stories are real and carry on coherent conversations that they do remember a few minutes later. Wernicke-Korsakoff syndrome can be fatal and difficult to manage. The Alzheimer’s Association reports that about a quarter of those battling Korsakoff syndrome will recover with sustained alcohol abstinence and proper treatment, half will see improved symptoms, and the other quarter may not notice a difference in symptoms or cognitive deficits.
Without question, alcohol can greatly disrupt brain functions and cognitive behaviors, which may become compounded with regular episodes of excessive drinking. Fortunately many of these negative side effects are reversible with time, proper care, and long-term sobriety.