Alcohol is one of the oldest used and misused drugs of human history.  Its presence extends back to prehistory and was present at least during the period of agricultural development.

Legality of Alcohol Use and Attitudes Towards Its Abuse

The use and abuse of alcohol is unique in today's society by virtue of its status as a "legal" drug that is, at least in part, government sanctioned.  The control of alcohol by local, state, and federal authorities provide legitimate sources of alcohol whereas many street drug sales are illegal.  The sale of alcohol and its taxation provide a source of revenue for these agencies.

Use and abuse of alcohol is also viewed very differently from that of illegal substances.  Alcohol is generally accepted by society and plays a role in the everyday life of many people, from the social context of bars to the martini lunches of businessmen.  Additionally, mild alcohol intoxication is often viewed as humourous by many colleagues or friends.  The use of alcohol in many of these instances is viewed as "deal-making", unwinding, or partying.  In most of these situations, the class or social strata of the individuals plays a major role in their perception of alcohol use and abuse.

A very different perception of alcohol abuse is evident when attitudes toward the homeless, street people, or under-privileged persons who abuse alcohol are examined.  These persons are often labelled as shiftless, good for nothing, drunks, and irresponsible.

In reality, the detrimental effects of alcohol use and abuse is not discriminatory and permeates all levels of society.

Ethanol, the specific type of alcohol found in abused beverages, is the product of fermentation of fruits, vegetables, or grains.  As the fermentation process occurs, sugars of these food substances are acted upon by yeast to form ethanol and carbon dioxide.  Typically, wines are made from fruits and range from 8-12% in alcohol content, while beers are made from grains (most often barley), hops, and malt and may range from 3-12% alcohol (often the allowable alcohol content for beer is set by individual states at a percent maximum alcohol content).  Vegetables (potato), bread, milk, or any other source of sugars may also be used to make alcoholic beverages.

As the content of alcohol increases, the viability of the yeast declines.  Normally, the yeast cannot survive in concentrations of alcohol greater than 14%.  Therefore, naturally occurring alcoholic beverages are rarely greater than 14% alcohol.  NOTE that they may be less than 14%.  The process may be arrested at any concentration lower that 14% alcohol.  During the middle ages the process of distillation was discovered.  This process involves the boiling of substance with the loss of a portion of the water while retaining all of the alcohol.  Consequently much stronger alcoholic beverages could be made.  Liquors and other distilled spirits may contain as much as 40-50% alcohol, on the average.  NOTE that 95% alcohol is available, but can cause severe damage if ingested straight.  It is diluted with non-alcoholic beverages prior to ingestion.  Distilled spirits are often made from fermented grains such as barley (Scotch), corn (bourbon), and rye (Canadian whiskey), or from sources as diverse as potatoes (Vodka) and juniper berries (gin).  Flavourings are often added to distilled liquors.  Typical equivalents of alcohol content in the U.S.A. are 1 - 1 ½ oz. of liquor   5 oz. wine   12 oz. beer.

Absorption
Absorption of ethanol begins in the stomach and continues throughout the length of the alimentary canal.  Following its absorption into the blood stream, ethanol readily enters most body tissues including the brain.  Peak blood alcohol concentration usually occurs 30-90 minutes following ingestion.  The central effects of alcohol correlate to its absorption and the amount in the blood stream and various factors can influence these rates and concentrations.  Typically, persons with more body fat achieve a lower concentration of blood alcohol that thinner people, due to the storage of the alcohol in fat.  Factors that affect the rate of absorption include the following:
The amount or speed at which the alcohol is ingested -- the greater the volume or the faster it is ingested, the higher faster the absorption and greater the blood alcohol level

Presence of food -- If alcohol is ingested during meals or on a full stomach, absorption takes place slower and the blood alcohol concentration is less, if it is taken on an empty stomach, absorption is faster and blood concentration is higher.

Concentration of the alcohol -- beverages that are higher in percent of alcohol present will produce a higher blood concentration faster than lower percent alcoholic beverages -- for example, a shot of whiskey will produce higher levels faster than the same amount diluted in water (which would essentially change the ethanol content from 40% to 20% or less)

Carbonation -- the presence of carbonation (as in champagne or mixing liquor with carbonated beverages such as soft drinks) will increase the rate of absorption

Temperature -- warming of the alcoholic beverage will also increase its rate of absorption

Metabolism
Ethanol is broken down in the body to a substance called acetaldehyde.  The "desirable" effects are due to the ethanol while many of the adverse effects (flushing, upset stomach) are due to the acetaldehyde.  The acetaldehyde is then broken down to acetic acid by an enzyme called acetaldehyde dehydrogenase.  The by products are then excreted by the body (NOTE that ethanol itself may also be excreted by the body through the lungs, sweat, saliva, and urine -- anywhere from 2-10 percent may be excreted by these pathways).  Certain races, Asians in particular, lack acetaldehyde dehydrogenase.  Therefore, they will exhibit the signs of acetaldehyde accumulation (facial flushing) more so than other races.  Metabolic differences also occur in men compared to women.  Due to these differences and the differences in fat:muscle ratio and overall weight, women will typically have higher blood levels of alcohol compared to men who have drunk the same amount of alcohol.  Alcohol clears the body at a relatively predictable rate (approximately 7 to 10 ml of ethanol/hr).  This clearance may be higher in persons who chronically use alcohol, due to a dispositional tolerance that develops.

Blood Alcohol Concentration (BAC)
This measurement reflects the amount drunk, the amount of ethanol absorbed and the amount metabolised and/or excreted over time.  It is a function of time (the longer after peak ethanol concentration, the lower the BAC.  Numerous tabular models exist to estimate the BAC based upon amount drunk, weight of the individual, time spent drinking, and gender.  These tables are guidelines and should not be interpreted as "gospel" in determining BAC.  In Oklahoma, A BAC between 0.06 to 0.099 mg % is designated as driving while impaired (DWI) while a BAC of 0.1 mg % or greater is designated as driving under the influence (DUI).  Follow this link to a discussion of Oklahoma Drunk Driving Laws.

Potential Benefits of Alcohol
Recent reports support the theory that alcohol may have beneficial effects on the cardiovascular system.  Alcohol causes vasodilatation, which helps to lower blood pressure (it is also this effect which makes the person feel warm -- the rationale behind the use of alcohol in cold weather -- HOWEVER, dilatation also speeds up the loss of body heat, therefore the use of alcohol in cold conditions actually causes the person's body temperature to DROP contributing to hypothermia).  Additionally, alcohol decreases the circulating levels of LDL (bad cholesterol) and increases the levels of HDL (good cholesterol), which decreases the risk of atherosclerosis and other heart diseases.  These effects are thought to be responsible for the low incidence of heart disease in France, where red wines are ingested on a frequent basis (NOTE that some researchers believe at least part of the effects may be due to components in wine other than alcohol).  HOWEVER, also NOTE that France has one of the highest incidents of liver cirrhosis (discussed below) that is probably also due to the high use of alcohol.

Low-Episode Effects

Sexual -- alcohol typical increases the desire for sexual activity in both males and females.  In females it also heightens the orgasmic experience while in men it decreases sexual performance by decreasing the erection and delaying ejaculation.

Psychological -- Alcohol is similar to the barbiturates in that the effect of the drug may be predicated by the mood of the individual.  Many people may plan to have a certain experience when they drink.  For instance, a person may plan to enjoy the drinking experience and the alcohol heightens this "good time" experience.  Alternately, some persons may plan the drink to relax them with the resultant effect of alcohol being a "mellow" experience.  Often times if the person has no preconceived plan for the drinking episode, the alcohol will magnify their mood at the time of ingestion (similar to the barbiturates).  For example a person who is angry may become more angry with drinking, a person who is jovial may become the life of the party.  Additionally, there are behaviour patterns that certain people when consistently exhibit when drinking -- these are classic presentations that are often described as the "happy" drunk, the "loving" drunk, the "crying" drunk, the "quiet" drunk, the "fighting" drunk, et c.  In each of the above instances, the effect is mediated primarily by a disinhibitory effect.

Disinhibition -- The primary effect of alcohol that is responsible for its abuse is its ability to cause disinhibition.  Recall, as discussed previously, that this effect permits behaviour in which the individual would not normally engage.  It decreases nerve activity throughout the brain, with the first areas being those that control behaviour (thus the disinhibition).  It also affects the activity of nerves that work through met-enkaphalin (which mediates pain), serotonin (which contributes to behaviour), dopamine (reward/pleasure), and GABA.  Recall that GABA is the neurotransmitter through which the sedative-hypnotics exert their influence.  It is believed that alcohol also exerts most of its effects by influencing this system.  This disinhibitory effect is also the cause of many of the violence that is associated with alcohol overuse (i.e. the rowdy football fan or the abusive husband).

High-Dose Episodes
Binge Drinking is defined as relatively infrequent (i.e. not daily), very high dose ethanol ingestion.
The initial responses are disinhibitory as described above.  Then, as BAC increases, the central depressant activity of ethanol causes a decrease in almost all nerves controlling function.  The person looses their coordination (ataxia, staggering), speech (becomes slurred), motor reflexes are slowed, body heat is lost, and the person becomes confused.  Additionally, the direct irritant effects of alcohol on the stomach may cause nausea and/or vomiting.

As the toxicity progresses (BAC around 0.2), the person may become semi-conscious.  If the person vomits during this phase, aspiration of the vomitus may occur which could at the least cause inflammation of the lungs and potentially cause death.  As BAC rises (0.4) the person enters alcohol toxicity.  They may become unconscious and death may occur to central depression (the cardiovascular and respiratory centres totally shut down).

Hangover -- The typical hangover represents a withdrawal syndrome that results from acute, excessive alcohol ingestion.  Signs and symptoms of hangover include nausea, vomiting, headache, dry mouth, thirst, dizziness, sensitivity to light and noise, and generalised depression.  These effects are due to the direct irritation of ethanol on the stomach, the loss of fluids (either through sweating, urination, or vomiting), and the CNS effects of ethanol.  At least a portion of these effects may be diminished by drinking fluids, pain relievers (such as aspirin -- but these may also cause stomach upset), and antacids.  While some of the effects of hangover are due directly to ethanol, many of the effects may be due to congeners present in the beverage.  Alcohol (especially distilled liquors) contain many other ingredients, such as other alcohols (propanol, butanol) and by products of the aging process.  Typically, the higher the number of congeners present, the greater the effects of the hangover.  Tannins in red wine and other constituents in wine and beer also contribute to the hangover effects.  Additionally, it appears that the common perception that mixing different alcohols or diluting liquor with mixers high in sugar do contribute to the overall hangover effect.

Sobering Up -- As mentioned above, alcohol is cleared from the body at a constant rate.  Therefore, there is little that can be done to hasten its excretion.  Coffee, cold showers, and typical attempts to sober a person up does not hasten the clearance of ethanol, but it may stimulate their brain, so that they may think more clearly.

Frequent High-Dose Use
Alcoholism
The chronic abuse of alcohol is most likely due to a combination of events that is common for most drugs of abuse (refer to the section on theories of addiction).  In general, approximately 10% of persons who drink will become addicted to alcohol.  Also, in general, males are more likely to become addicted than females, and at a younger age than females.  There is no "typical" alcoholic.  The abuse may be social or solitary and the person may be affluent or homeless.
Blackouts -- Many persons who abuse alcohol may experience episodes during heavy drinking where they are conscious, performing everyday tasks, but do not remember any period during the time of their drinking.  (An episode where the period is partially remembered is termed a brown-out).  This is due, at least in part, to the CNS depressant effects on short-tern memory.

Tolerance -- As with most other drugs of abuse, tolerance develops to the effects of alcohol.  The tolerance to alcohol arises from three different types.
Dispositional tolerance results from the ability of ethanol to enhance its own metabolism.  Ethanol induces the liver to speed up metabolism.  Therefore, the ethanol is cleared from the body faster, reducing its effect.

Pharmacodynamic tolerance also develops to ethanol.  This results from changes in receptor number, thus reducing the effect of ethanol.

Behavioural tolerance may also develop, in which the abuser learns to cope with the effects of alcohol.

Withdrawal -- Chronic use of alcohol and the development of tolerance can, upon stopping drinking, produce intense, severe, potentially lethal, withdrawal symptoms.  Alcohol withdrawal signs and symptoms include tremors, sweating, cramps, hallucinations (auditory, visual, and tactile) , stomach pain, and potentially seizures (approximately 12% of patients).  The combination of severe hallucinations and tremors/seizures is called delirium tremens or DTs.  If untreated, 10-20% of patients that experience DT may die.  A patient in DTs must be given symptomatic and supportive therapy (anti-convulsants for the seizures, fluids, electrolytes to correct fluid loss).  Withdrawal symptoms are often lessened with the administration of sedative-hypnotics such as Librium® (chlordiazepoxide), a long-acting benzodiazepine that will decrease the risk to the patient of complicated withdrawal.  However, the administration of this or similar drugs lengthens the time required for withdrawal, necessitating close monitoring of the patient.
Long-Term Effects
Heart -- Chronic excess ethanol ingestion can cause numerous toxic effects to the cardiovascular system.  These include hypertension, coronary artery disease, and arrhythmias.  The classic case of chronic alcoholic heart disease in ethanolic cardiomyopathy.  As the various types of damage to the heart occur, the heart begins to loose its function and begins to fail.  The heart becomes enlarged to try to compensate and fails further.  Death due to chronic alcoholism is often the result of liver failure combined with heart failure.  Typical autopsy findings reveal a heart that may be twice the size of the heart of a non-drinker.

Liver Toxicity -- Ethanol causes the accumulation of fat in the liver.  Overtime this causes liver damage that must be repaired.  As scar tissue appears in the liver, it become fibrotic.  If the organ is exposed to continuous ethanol, further damage occurs, leading to further fibrosis and finally the liver develops cirrhosis, in which the liver is essentially scar tissue and looses its function (NOTE that when this happens, the liver looses its ability to metabolise ethanol.  Therefore the dispositional tolerance is lost, and ethanolic effects become much more pronounced.)

Gastrointestinal Tract -- Alcohol increases stomach acid and slows the GI tract.  Chronic use will cause gastritis both stomach and duodenal ulcers.

Reproductive System -- Alcohol will decrease fertility in both males and females.  It may also cause menstrual irregularities and early menopause in women who are heavy drinkers.  It may cause œstrogenic effects in men.

Immune System -- Chronic alcohol ingestion weakens the immune system, leading to an increased risk of infections.

Nutritional Deficiencies -- Ethanol is a dietary source of energy.  However, it contains no nutritional value (no vitamins or minerals).  Therefore, many alcoholics will receive the energy and feel no need to eat for nutrition's sake.  Additionally, alcoholics who are poor will often forsake food for the alcohol.  Consequently, chronic states of malnutrition are common in alcoholic patients.  Therefore, these patients are at risk of developing classic nutritional deficit disorders such as scurvy, beri-beri, rickets, pellagra, and anæmia (due to malnutrition and blood loss by bleeding ulcers).  One type of nutritional deficit that occurs more commonly in alcoholics and is potentially severe is the deficiency associated with vitamin B1 (thiamine).  Thiamine deficiency coupled with the hepatic effects will cause a condition called WERNICKE-KORSAKOFF syndrome.  This condition is characterised by hepatic and cerebral œdema (liver and brain swelling) that is potentially irreversible.  Standard therapy with the admission of chronic alcoholics to hospital includes the intravenous administration of thiamine to prevent this syndrome.

Alcohol Use And Mental State -- Many persons with diagnosed mental disease are prone to alcohol abuse.  The incidence of alcohol use in higher in persons diagnosed with depression, schizophrenia, chronic anxiety, and bipolar affective disorder (manic depression), than in the general population.  The exact relationship between mental disease and alcohol use in not well understood (i.e. does the cause of the disorder also cause the patient to drink or does the person drink because of the disease?).  Alcohol use may also result from transient mental states such as boredom, restlessness, or acute anxiety and exogenous depression.

Injury and Accident -- Since ethanol impairs response time and judgement, it is often the cause of serious or lethal accidents, including those related to motor vehicles (some studies indicated that half of car accidents involve the use of alcohol) such as cars, boats, planes; heavy machinery, farm equipment.  The choice by the alcohol user to operate such machinery or engage in other activities that could result in harm or injury is often the result of its disinhibitory effects and a denial that they are impaired.

Suicide -- The suicide rate among alcoholics is higher than that for the general population.  This may reflect other mental illness (depression) in the user or it may indicate the effect that alcohol has on their life (abuse lead to many of the same effects as other drugs such as destruction of family life or abandonment by friends thus removing the support circle that individuals need).

Mortality -- In addition to death by misadventure (accidents or suicide as described above), ethanol use shortens the life-span of a chronic user by 4 (cancer, heart disease) to 22 years (chronic liver failure).

Fœtal Alcohol Syndrome
In addition to the ability of ethanol to cause miscarriage or infant death, ethanol ingestion during pregnancy may produce teratogenic effects (changes in the development of the fœtus that result in birth defects).  In its mildest form, fœtal alcohol effects produces only mild abnormalities that may only be discovered as the child grows.  In its more severe form, fœtal alcohol syndrome results in children who have severe deformation of brain structure and function (resulting in profound learning impairment), physical deformities (shortened eye openings, thin upper lip, flattened midface, cleft palate and heart and limb defects), and behavioural changes (weak suckling response, sleep disturbances, and hyper-reactivity (jitteriness, nervousness, trembling).  The specific physical deformities are determined by the specific time during pregnancy that alcohol ingestion occurred.  Since different organ systems and structures develop during different times during gestation, the organ that is undergoing development at the time of exposure will be most affected.  Also, since the brain develops throughout gestation, central damage may occur at anytime during pregnancy.  However, the greatest damage is probably during the first trimester.

The minimal amount of alcohol required to produce these changes has not been elucidated.  It appears that the most profound effects are produced in response to extremely high surges in BAC of the mother (binge-type drinking).  HOWEVER, even minimal amounts of alcohol (one drink) have to potential to cause birth defects.  Therefore mothers should be warned to abstain totally during pregnancy.

Recent research also supports the view that children of alcoholic parents may exhibit learning impairment without organ brain disease (no structural abnormalities are present).  These learning deficits are often difficult to assess due to their subtlety but appear to involve verbal, thinking, planning, memory, motor, and visual/spatial skills.

Epidemiology of Alcohol Abuse -- The use of alcohol differs widely from country to country and often reflects that attitude of the culture towards drinking.  A very similar situation exists on a smaller scale when comparing the use of alcohol in different families, with traditions and views on alcohol use, abuse, and history, influencing each family in separate ways.

General trends of alcohol use

Typically men drink more per episode than women and chronic alcohol abuse (alcoholism) is greater in men.  Men also tend to start at a younger age than women.

The adverse health consequences are greater in women than men.  More women die from the liver and/or heart failure associated with chronic alcohol use than men.

Typically, students who drink more also do more poorly in their class work than students who drink less.  One study indicated that students receiving D/F grades averaged 10 drinks per week, C - 7 drinks/wk, B - 5 drinks/week, and A - 3 drinks/week.

The elderly typically continue the behaviours that were initiated during their youth.  It is rare for an elderly person to become an alcoholic (although their use may increase due to loneliness, retirement, et c.).

According to one study comparing alcohol use across three racial groups, heavy alcohol use is greatest in Hispanics followed closely by Caucasians and least in African-Americans.  However, the total spread between the groups differed only by 1.7 percentage points.  Alcoholism occurs less in Asians (perhaps due to cultural differences and perhaps due to the increased incidence of adverse effects discussed previously), although use is higher in young, educated Asian Americans than in the subpopulation as a whole.  Alcohol use among Native Americans varies widely from tribe to tribe and among specific locations.  Generally, alcohol use in this subpopulation is not radically different from the American population statistics.

As with most "generalisations" a sweeping statement of alcohol use cannot be made reliably.  Considering subpopulations, gender, economic class, or level of education, alcohol use varies greatly and most often reflects the factors of drug abuse in individual persons (as previously discussed) than any of the above factors.  Additionally, the use of alcohol may be exhibited as any of the various stages of drug abuse -- abstention, experimentation, social/recreational use, habituation, abuse, or addiction.