Alcohol (drug)

 Alcohol (drug)

Alcohol, sometimes referred to by the chemical name ethanol, is a psychoactive drug that is the active ingredient in drinks such as beer, wine, and distilled spirits (hard liquor). It is one of the oldest and most common recreational substances, causing the characteristic effects of alcohol intoxication ("drunkenness"). Among other effects, alcohol produces happiness and euphoria, decreased anxiety, increased sociability, sedation, impairment of cognitive, memory, motor, and sensory function, and generalized depression of central nervous system function. Ethanol is only one of several types of alcohol, but it is the only type of alcohol that is found in alcoholic beverages or commonly used for recreational purposes; other alcohols such as methanol and isopropyl alcohol are significantly more toxic. A mild, brief exposure to isopropanol, being only moderately more toxic than ethanol, is unlikely to cause any serious harm. Methanol, being profoundly more toxic than ethanol, is lethal in quantities as small as 10–15 milliliters (2–3 tsp).

Alcohol has a variety of short-term and long-term adverse effects. Short-term adverse effects include generalized impairment of neurocognitive function, dizziness, nausea, vomiting, and hangover-like symptoms. Alcohol is addictive to humans, and can result in alcohol use disorder, dependence and withdrawal. It can have a variety of long-term adverse effects on health, for instance liver damage, brain damage, and its consumption is the fifth leading cause of cancer. The adverse effects of alcohol on health are most important when it is used in excessive quantities or with heavy frequency. However, some of them, such as increased risk of certain cancers, may occur even with light or moderate alcohol consumption. In high amounts, alcohol may cause loss of consciousness or, in severe cases, death.

Alcohol works in the brain primarily by increasing the effects of a neurotransmitter called γ-aminobutyric acid, or GABA. This is the major inhibitory neurotransmitter in the brain, and by facilitating its actions, alcohol suppresses the activity of the central nervous system. The substance also directly affects a number of other neurotransmitter systems including those of glutamate, glycine, acetylcholine, and serotonin. The pleasurable effects of alcohol ingestion are the result of increased levels of dopamine and endogenous opioids in the reward pathways of the brain. Alcohol also has toxic and unpleasant actions in the body, many of which are mediated by its byproduct acetaldehyde.

Alcohol has been produced and consumed by humans for its psychoactive effects for almost 10,000 years. Drinking alcohol is generally socially acceptable and is legal in most countries, unlike with many other recreational substances. However, there are often restrictions on alcohol sale and use, for instance a minimum age for drinking and laws against public drinking and drinking and driving. Alcohol has considerable societal and cultural significance and has important social roles in much of the world. Drinking establishments, such as bars and nightclubs, revolve primarily around the sale and consumption of alcoholic beverages, and parties, festivals, and social gatherings commonly involve alcohol consumption. Alcohol is unique in that it is the only drug that damages others more than the user. It is related to various societal problems, including drunk driving, accidental injuries, sexual assaults, domestic abuse, and violent crime. Alcohol remains illegal for sale and consumption in a number of countries, mainly in the Middle East. While some religions, including Islam, prohibit alcohol consumption, other religions, such as Christianity and Shinto, utilize alcohol in sacrament and libation.

Use and effects

Main articles: Alcohols (medicine), Short-term effects of alcohol consumption, Alcohol intoxication, and Long-term effects of alcohol

See also: Alcohol and health § Short-term effects

Ethanol is typically consumed as a recreational substance by mouth in the form of alcoholic beverages such as beer, wine, and spirits. It is commonly used in social settings due to its capacity to enhance sociability.

The amount of ethanol in the body is typically quantified by blood alcohol content (BAC); weight of ethanol per unit volume of blood. Small doses of ethanol, in general, are stimulant-like and produce euphoria and relaxation; people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgement. At higher dosages (BAC > 1 g/L), ethanol acts as a central nervous system depressant, producing at progressively higher dosages, impaired sensory and motor function, slowed cognition, stupefaction, unconsciousness, and possible death. Ethanol is commonly consumed as a recreational substance, especially while socializing, due to its psychoactive effects.

Toxicity

See also: Alcohol and health and Health effects of wine

Alcohol has a variety of short-term and long-term adverse effects. It also has reinforcement-related adverse effects, including addiction, dependence, and withdrawal.

Social harm

Alcohol causes a plethora of detrimental effects in society. It is highly associated with drinking in public, impaired social distancing, passive drinking, drunk dialing, drunk driving, sexual risk-taking or drug facilitated sexual assault (especially with caffeinated alcoholic drinks), and both violent and non-violent crime. About one-third of arrests in the United States involve alcohol misuse. Many emergency room visits also involve alcohol use. As many as 15% of employees show problematic alcohol-related behaviors in the workplace, such as drinking before going to work or even drinking on the job. Heavy drinking is associated with vulnerability to injury, marital discord, and domestic violence. Alcohol use is directly related to considerable morbidity and mortality, for instance due to overdose and alcohol-related health problems.

Alcohol-related crimes

Main articles: Alcohol-related crime and Drug-related crime

Automobile accidents

Main articles: Drunk driving and Driving under influence

A 2002 study found 41% of people fatally injured in traffic accidents were in alcohol-related crashes. Misuse of alcohol is associated with more than 40% of deaths that occur in automobile accidents every year. The risk of a fatal car accident increases exponentially with the level of alcohol in the driver's blood. Most drunk driving laws in the United States governing the acceptable levels in the blood while driving or operating heavy machinery set typical upper limits of legal blood alcohol content (BAC) at 0.08%.

Sexual assault

See also: Drug-facilitated sexual assault and Date rape drug

Alcohol is often used to facilitate sexual assault or rape. Over 50% of reported rapes involve alcohol. It is the most commonly used date rape drug.

Violent crime

Main article: Alcohol-related crime

Over 40% of all assaults and 40 to 50% of all murders involve alcohol. More than 43% of violent encounters with police involve alcohol. Alcohol is implicated in more than two-thirds of cases of intimate partner violence. In 2002, it was estimated that 1 million violent crimes in the United States were related to alcohol use. Alcohol is more commonly associated with both violent and non-violent crime than are drugs like marijuana.

Health consequences

Main articles: Alcohol and health and Alcoholism § Moderate drinking

Alcohol use disorder is a major problem and many health problems as well as death can result from excessive alcohol use. Alcohol dependence is linked to a lifespan that is reduced by about 12 years relative to the average person. In 2004, it was estimated that 4% of deaths worldwide were attributable to alcohol use. Deaths from alcohol are split about evenly between acute causes (e.g., overdose, accidents) and chronic conditions. The leading chronic alcohol-related condition associated with death is alcoholic liver disease. Alcohol dependence is also associated with cognitive impairment and organic brain damage. Some researchers have found that even one alcoholic drink a day increases an individual's risk of health problems by 0.4%.

Adverse effects

Short-term effects

Main articles: Short-term effects of alcohol consumption and Alcohol intoxication

Central nervous system impairment

Alcohol causes generalized central nervous system depression, is a positive allosteric GABAA modulator and is associated and related with cognitive, memory or memory loss, motor, and sensory impairment. It slows and impairs cognition and reaction time and the cognitive skills, impairs judgement, interferes with motor function resulting in motor incoordination, loss of balance, confusion, sedation, numbness and slurred speech, impairs memory formation, and causes sensory impairment. At high concentrations, it can induce amnesia, analgesia, spins, stupor, and unconsciousness as result of high levels of ethanol in blood.

At very high concentrations, alcohol can cause anterograde amnesia, markedly decreased heart rate, pulmonary aspiration, positional alcohol nystagmus (PAN), respiratory depression, shock, coma and death can result due to profound suppression of central nervous system function alcohol overdose and can finish in consequent dysautonomia.

Gastrointestinal effects

Alcohol can cause nausea and vomiting in sufficiently high amounts (varies by person).

Alcohol stimulates gastric juice production, even when food is not present, and as a result, its consumption stimulates acidic secretions normally intended to digest protein molecules. Consequently, the excess acidity may harm the inner lining of the stomach. The stomach lining is normally protected by a mucosal layer that prevents the stomach from, essentially, digesting itself. However, in patients who have a peptic ulcer disease (PUD), this mucosal layer is broken down. PUD is commonly associated with the bacteria H. pylori. H. pylori secrete a toxin that weakens the mucosal wall, which as a result lead to acid and protein enzymes penetrating the weakened barrier. Because alcohol stimulates a person's stomach to secrete acid, a person with PUD should avoid drinking alcohol on an empty stomach. Drinking alcohol causes more acid release, which further damages the already-weakened stomach wall. Complications of this disease could include a burning pain in the abdomen, bloating and in severe cases, the presence of dark black stools indicate internal bleeding. A person who drinks alcohol regularly is strongly advised to reduce their intake to prevent PUD aggravation.

Ingestion of alcohol can initiate systemic pro-inflammatory changes through two intestinal routes: (1) altering intestinal microbiota composition (dysbiosis), which increases lipopolysaccharide (LPS) release, and (2) degrading intestinal mucosal barrier integrity – thus allowing this (LPS) to enter the circulatory system. The major portion of the blood supply to the liver is provided by the portal vein. Therefore, while the liver is continuously fed nutrients from the intestine, it is also exposed to any bacteria and/or bacterial derivatives that breach the intestinal mucosal barrier. Consequently, LPS levels increase in the portal vein, liver and systemic circulation after alcohol intake. Immune cells in the liver respond to LPS with the production of reactive oxygen species (ROS), leukotrienes, chemokines and cytokines. These factors promote tissue inflammation and contribute to organ pathology.

Allergic-like reactions

Main articles: Alcohol-induced respiratory reactions and Alcohol flush reaction

Ethanol-containing beverages can cause alcohol flush reactions, exacerbations of rhinitis and, more seriously and commonly, bronchoconstriction in patients with a history of asthma, and in some cases, urticarial skin eruptions, and systemic dermatitis. Such reactions can occur within 1–60 minutes of ethanol ingestion, and may be caused by:

genetic abnormalities in the metabolism of ethanol, which can cause the ethanol metabolite, acetaldehyde, to accumulate in tissues and trigger the release of histamine, or

true allergy reactions to allergens occurring naturally in, or contaminating, alcoholic beverages (particularly wine and beer), and

other unknown causes.