Alcohol abuse is said to be most common in people aged between 15 and 24 years, according to Moreira 2009. However, this particular study of 7275 college students in England collected no comparative data from other age groups or countries.

Causes of alcohol abuse are complex and are likely the combination of many factors, from coping with stress to childhood development. The US Department of Health & Human Services identifies several factors influencing adolescent alcohol use, such as risk-taking, expectancies, sensitivity and tolerance, personality and psychiatric comorbidity, hereditary factors, and environmental aspects. Studies show that child maltreatment such as neglect, physical, and/or sexual abuse, as well as having parents with alcohol abuse problems, increases the likelihood of that child developing alcohol use disorders later in life. According to Shin, Edwards, Heeren, & Amodeo (2009), underage drinking is more prevalent among teens that experienced multiple types of childhood maltreatment regardless of parental alcohol abuse, putting them at a greater risk for alcohol use disorders. Genetic and environmental factors play a role in the development of alcohol use disorders, depending on age. The influence of genetic risk factors in developing alcohol use disorders increase with age ranging from 28% in adolescence and 58% in adults.

The impact of alcohol on weight-gain is contentious: some studies find no effect, others find decreased or increased effect on weight gain.

Alcohol use increases the risk of chronic gastritis (stomach inflammation); it is one cause of cirrhosis, hepatitis, and pancreatitis in both its chronic and acute forms.

A study concluded, "Mild to moderate alcohol consumption is associated with a lower prevalence of the metabolic syndrome, with a favorable influence on lipids, waist circumference, and fasting insulin. This association was strongest among whites and among beer and wine drinkers." This is also true for Asians. A J-curve association between alcohol intake and metabolic syndrome was found: "The results of the present study suggest that the metabolic syndrome is negatively associated with light alcohol consumption (1–15 g alcohol/d) in Korean adults". However, "odds ratios for the metabolic syndrome and its components tended to increase with increasing alcohol consumption."

The cause of alcohol abuse is complex. Alcohol abuse is related to economic and biological origins and is associated with adverse health consequences. Peer pressure influences individuals to abuse alcohol; however, most of the influence of peers is due to inaccurate perceptions of the risks of alcohol abuse. According to Gelder, Mayou and Geddes (2005) easy accessibility of alcohol is one of the reasons people engage in alcohol abuse as this substance is easily obtained in shops. Another influencing factor among adolescents and college students are the perceptions of social norms for drinking; people will often drink more to keep up with their peers, as they believe their peers drink more than they actually do. They might also expect to drink more given the context (e.g. sporting event, fraternity party, etc.). This perception of norms results in higher alcohol consumption than is normal.

Alcohol abuse is also associated with acculturation, because social and cultural factors such as an ethnic group’s norms and attitudes can influence alcohol abuse.

In order to maintain high-quality performance, some musicians take chemical substances. Some musicians take drugs or alcohol to deal with the stress of performing. As a group they have a higher rate of substance abuse. The most common chemical substance which is abused by pop musicians is cocaine, because of its neurological effects. Stimulants like cocaine increase alertness and cause feelings of euphoria, and can therefore make the performer feel as though they in some ways ‘own the stage’. One way in which substance abuse is harmful for a performer (musicians especially) is if the substance being abused is aspirated. The lungs are an important organ used by singers, and addiction to cigarettes may seriously harm the quality of their performance. Smoking causes harm to alveoli, which are responsible for absorbing oxygen.

Street children in many developing countries are a high risk group for substance misuse, in particular solvent abuse. Drawing on research in Kenya, Cottrell-Boyce argues that "drug use amongst street children is primarily functional – dulling the senses against the hardships of life on the street – but can also provide a link to the support structure of the ‘street family’ peer group as a potent symbol of shared experience."

About 12% of American adults have had an alcohol dependence problem at some time in their life. In the UK the NHS estimates that around 9% of men and 4% of UK women show signs of alcohol dependence.

Based on combined data from SAMHSA's 2004–2005 National Surveys on Drug Use & Health, the rate of past-year alcohol dependence or abuse among persons aged 12 or older varied by level of alcohol use: 44.7% of past month heavy drinkers, 18.5% binge drinkers, 3.8% past month non-binge drinkers, and 1.3% of those who did not drink alcohol in the past month met the criteria for alcohol dependence or abuse in the past year. Males had higher rates than females for all measures of drinking in the past month: any alcohol use (57.5% vs. 45%), binge drinking (30.8% vs. 15.1%), and heavy alcohol use (10.5% vs. 3.3%), and males were twice as likely as females to have met the criteria for alcohol dependence or abuse in the past year (10.5% vs. 5.1%).

Medical organizations strongly discourage drinking alcohol during pregnancy. Alcohol passes easily from the mother's bloodstream through the placenta and into the bloodstream of the fetus, which interferes with brain and organ development. Alcohol can affect the fetus at any stage during pregnancy, but the level of risk depends on the amount and frequency of alcohol consumed. Regular heavy drinking and binge drinking (four or more drinks on any one occasion) pose the greatest risk for harm, but lesser amounts can cause problems as well. There is no known safe amount or safe time to drink during pregnancy.

Prenatal alcohol exposure can lead to fetal alcohol spectrum disorders (FASDs). The most severe form of FASD is fetal alcohol syndrome (FAS). Problems associated with FASD include facial anomalies, low birth weight, stunted growth, small head size, delayed or uncoordinated motor skills, hearing or vision problems, learning disabilities, behavior problems, and inappropriate social skills compared to same-age peers. Those affected are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and develop substance use disorders themselves.

A complex mixture of genetic and environmental factors influences the risk of the development of alcoholism. Genes that influence the metabolism of alcohol also influence the risk of alcoholism, and may be indicated by a family history of alcoholism. One paper has found that alcohol use at an early age may influence the expression of genes which increase the risk of alcohol dependence. Individuals who have a genetic disposition to alcoholism are also more likely to begin drinking at an earlier age than average. Also, a younger age of onset of drinking is associated with an increased risk of the development of alcoholism, and about 40 percent of alcoholics will drink excessively by their late adolescence. It is not entirely clear whether this association is causal, and some researchers have been known to disagree with this view.

Severe childhood trauma is also associated with a general increase in the risk of drug dependency. Lack of peer and family support is associated with an increased risk of alcoholism developing. Genetics and adolescence are associated with an increased sensitivity to the neurotoxic effects of chronic alcohol abuse. Cortical degeneration due to the neurotoxic effects increases impulsive behaviour, which may contribute to the development, persistence and severity of alcohol use disorders. There is evidence that with abstinence, there is a reversal of at least some of the alcohol induced central nervous system damage. The use of cannabis was associated with later problems with alcohol use. Alcohol use was associated with an increased probability of later use of tobacco, cannabis, and other illegal drugs.

A study published in the British Medical Journal on 10 July 2014 investigated the correlation between human variants of the ADH1B gene, which codes for the ADH1B enzyme (Alcohol dehydrogenase 1B), and cardiovascular health. The study concluded that carriers of one specific variant of this gene (A-allele of ADH1B rs1229984), which is associated with lower alcohol consumption, '...had a more favourable cardiovascular profile and a reduced risk of coronary heart disease than those without the genetic variant.' The study's authors extrapolated from this finding to suggest that '...reduction of alcohol consumption, even for light to moderate drinkers, is beneficial to health.'

This study contradicts previous findings on the causal relationship between light alcohol consumption and cardiovascular health, and has been criticized on its methodology by members of the International Scientific Forum on Alcohol Research, which stated in its analysis that '...[there are] questions about making generalized statements about the effects of alcohol on disease based on results from the analysis of a single nucleotide polymorphism of a gene.'

Moreover, the study fails to explain or discount previous findings that show a causal link between alcohol intake and cardiovascular health that can not be accounted for by genetic predisposition alone.

Treatments for alcohol dependence can be separated into two groups, those directed towards severely alcohol-dependent people, and those focused for those at risk of becoming dependent on alcohol. Treatment for alcohol dependence often involves utilizing relapse prevention, support groups, psychotherapy, and setting short-term goals. The Twelve-Step Program is also a popular process used by those wishing to recover from alcohol dependence.

Complications of benzodiazepine abuse include drug-related deaths due to overdose especially in combination with other depressant drugs such as opioids. Other complications include: blackouts and memory loss, paranoia, violence and criminal behaviour, risk-taking sexual behaviour, foetal and neonatal risks if taken in pregnancy, dependence, withdrawal seizures and psychosis. Injection of the drug carries risk of: thrombophlebitis, deep vein thrombosis, deep and superficial abscesses, pulmonary microembolism, rhabdomyolysis, tissue necrosis, gangrene requiring amputation, hepatitis B and C, as well as blood borne infections such as HIV infection (caused by sharing injecting equipment). Long-term use of benzodiazepines can worsen pre-existing depression and anxiety and may potentially also cause dementia with impairments in recent and remote memory functions.

Use is widespread among amphetamine users, with those that use amphetamines and benzodiazepines having greater levels of mental health problems and social deterioration. Benzodiazepine injectors are almost four times more likely to inject using a shared needle than non-benzodiazepine-using injectors. It has been concluded in various studies that benzodiazepine use causes greater levels of risk and psycho-social dysfunction among drug misusers.

Poly-drug users who also use benzodiazepines appear to engage in more frequent high-risk behaviors. Those who use stimulant and depressant drugs are more likely to report adverse reactions from stimulant use, more likely to be injecting stimulants and more likely to have been treated for a drug problem than those using stimulant but not depressant drugs.

Little attention has focused on the degree that benzodiazepines are abused as a primary drug of choice, but they are frequently abused alongside other drugs of abuse, especially alcohol, stimulants and opiates. The benzodiazepine most commonly abused can vary from country to country and depends on factors including local popularity as well as which benzodiazepines are available. Nitrazepam for example is commonly abused in Nepal and the United Kingdom, whereas in the United States of America where nitrazepam is not available on prescription other benzodiazepines are more commonly abused. In the United Kingdom and Australia there have been epidemics of temazepam abuse. Particular problems with abuse of temazepam are often related to gel capsules being melted and injected and drug-related deaths. Injecting most benzodiazepines is dangerous because of their relative insolubility in water (with the exception of midazolam), leading to potentially serious adverse health consequences for users.

Benzodiazepines are a commonly misused class of drug. A study in Sweden found that benzodiazepines are the most common drug class of forged prescriptions in Sweden. Concentrations of benzodiazepines detected in impaired motor vehicle drivers often exceeding therapeutic doses have been reported in Sweden and in Northern Ireland. One of the hallmarks of problematic benzodiazepine drug misuse is escalation of dose. Most licit prescribed users of benzodiazepines do not escalate their dose of benzodiazepines.

Acute intoxication, such as binge drinking and alcoholism, are known potent risk factors for suicide. Binge drinking is also associated with an increased risk of unplanned sex, unprotected sex, unplanned pregnancies, and an increased risk of HIV infection. 10 percent of women and 19 percent of men have reported being assaulted as a result of alcohol. Males who drink more than 35 units of alcohol per week report being physically hurt as a result of alcohol, and 15 percent report physically hurting others as a result of their drinking. Almost 16 percent of binge drinkers report being taken advantage of sexually, and 8 percent report taking advantage of another person sexually as a result of alcohol within a 1-year period. Heavy drinkers cause approximately 183,000 rapes and sexual assaults, 197,000 robberies, 661,000 aggravated assaults, and 1.7 million simple assaults each year. Binge drinking has been associated with high odds of divorce, spousal abuse, and poor job performance. Binge drinking can cause adverse effects on the body including effects on blood homeostasis and its circadian variation, cardiac rhythm, ischaemic heart disease, blood pressure, white blood cell activity, female reproductive hormone levels as well as adverse effects on the fetus. There is also evidence from animal studies that binge drinking causes brain damage. Binge drinking has been associated with lower abdominal pain in women. Ketoacidosis can occur in individuals who chronically abuse alcohol and have a recent history of binge drinking. Alcohol affects brain development quite significantly especially during adolescence when the brain is still developing. The main lobes that are involved in decision making and complex thought processes are undergoing their final development phase during adolescence and binge drinking can negatively stunt the growth of these frontal lobes.

Marquis states how "Adolescent alcohol

use is not an acceptable rite of passage but a serious threat to adolescent

development and health, as the statistics related to adolescent impairment,

injury, and death attest." Research shows how an adolescent

makes the decision to consume alcohol because they are influenced by various

factors. "These factors include normal maturational changes that all

adolescents experience; genetic, psychological and social factors specific to

each adolescent and the various social and cultural environments that surround

adolescent, including their families, schools and communities". It is also

shown that early onset of alcohol intake can lead to high levels of alcohol use

in adulthood.

Alcoholism throughout adolescents is increasing yearly for a number of different reasons. These reasons include:

- Availability of alcohol

- Peer pressure

- Role model

- Television

- Anxiety or stress

The high levels of binge drinking among young people and the adverse consequences that include increased risk of alcoholism as an adult and liver disease make binge drinking a major public health issue. Recent research has found that young college binge drinkers who drink 4/5+ drinks on more than 3 occasions in the past 2 weeks are statistically 19 times more likely to develop alcoholism than non-binge drinkers, though the direction of causality remains unclear. This is particularly interesting as drinking for the sole purpose of getting drunk, remains a major health and social problem on college campuses across the United States. Heavy and regular binge drinking during adolescence is associated with an increased risk of alcoholism. Approximately 40 percent of alcoholics report heavy drinking during adolescence. Repeated episodes of excessive drinking, especially at an early age, are thought to cause a profound increase in the risk of developing an alcohol-related disorder (ICD-10, harmful use/dependence syndrome). Heavy drinking is also closely associated with depression. Those with severe depression have higher rates of alcohol abuse than those with low depression. College students who are depressed are more susceptible to use alcohol than college students who are not depressed. In a study conducted by Harvard University it was found that about 32% of students surveyed were diagnosable for alcohol abuse and about 6% were diagnosed as alcohol dependent. Binge drinking is also becoming an increasing problem in Australian adolescents, the Australian School Students Alcohol and Drug survey conducted by the National Cancer Council discovered that around 33 percent of students between Years 7 and 11 consumed alcohol in the week leading up to the survey, they also found that 10 percent of the students participated in binge drinking at a consumption level which is considered dangerous to adults. When the survey results were separated into age groups the findings were that 13 percent of 15-year-old's and 22 percent of 17-year-old's had alcohol consumption levels above the daily maximum suggested to adults and that 20 percent of 17-year-old's had a consumption level of alcohol considered risky to adults.

Other risk factors that influence the development of alcohol abuse or alcoholism include social and genetic factors. Several researchers have found that starting drinking before the age of 15 is associated with a fourfold increased risk for developing alcoholism compared to people that delay drinking until age 20 or later. It has been estimated by some that if the age at which people started drinking could be delayed to age 20, there would be a 50 percent reduction in the number of cases of alcohol use disorder. However, it is unclear whether this is a causal relationship, or a function of confounding familial (and other) factors associated with both age at first drink and propensity for alcoholism.

The main cause of death among adolescents as a result of binge drinking is road traffic accidents; a third of all fatal road traffic accidents among 15- to 20-year-olds are associated with drinking alcohol. Cyclists and pedestrians are likely to have less spatial awareness and concentration while travelling after binge drinking and, also, it is more common that adolescents that binge-drink drive drunk or are the passenger of a drunk driver. It has been found that 50 percent of all head injuries in adolescents in the US are associated with alcohol consumption. Violence and suicide combine to become the third-most-common cause of death associated with binge drinking among adolescents. The suicide risk in adolescents is more than 4 times higher among binge drinkers than non-binge drinking adolescents.

Earlier sexual activity, increased changing of sexual partners, higher rate of unwanted (teenage) pregnancy, higher rate of sexually transmitted diseases, infertility, and alcohol-related damage to the fetus during pregnancy is associated with binge drinking. Female binge drinkers are three times more likely to be victims of sexual assault; 50 percent of adolescent girls reporting sexual assault were under the influence of alcohol or another psychotropic substance at the time.

Adolescents who regularly participated in binge drinking for several years show a smaller hippocampus brain region, in particular those who began drinking in early adolescence. Heavy binge drinking is associated with neurocognitive deficits of frontal lobe processing and impaired working memory as well as delayed auditory and verbal memory deficits. Animal studies suggest that the neurodegenerative effects of alcohol abuse during adolescence can be permanent. Research in humans, which utilised sophisticated brain scanning technology suggests that in adolescent teenagers, drinking more than 4 or 5 drinks once or twice a month results in subtle damage to the teenagers developing brain tissue, in particular the white matter. However, this research is primarily cross-sectional and done with fairly small sample sizes, making causality less certain.

Several studies have been conducted to discover if there is a link between binge drinking in adolescent years and becoming a chronic alcohol consumer when they transition into adulthood. A particular study conducted by the National Longitudinal Survey of Youth found that harmful drinking during adolescent years was significantly associated with the continuance of dangerous levels of alcohol consumption into adulthood years.

Binge drinking occurs when students drink large amounts of alcohol in a relatively short space of time in order to feel the full effects of alcohol consumption. The National Institute of Alcohol Abuse and Alcoholism defines binge drinking as a pattern of drinking that brings a person's blood alcohol concentration, also known as BAC, to 0.08 grams percent or above. This is usually seen when men consume five or more drinks, and when women consume four or more drinks in a two-hour time period.

Young adults who participate in binge drinking experience higher rates of physical and sexual assault, and unwanted, unplanned, and unprotected sexual activity. There are also links between heavy alcohol consumption and depression.

The motivations among young students have changed as well. In recent years, more students are drinking with the intended purpose of getting drunk.

The combination of self-starvation and alcohol abuse can lead to an array of physical and psychological consequences. For example, drinking in a state of malnutrition can predispose individuals to a higher rate of blackouts, alcohol poisoning, alcohol-related injury, violence, or illness. Drinking on an empty stomach allows ethanol to reach the blood system at a swifter pace and raises one's blood alcohol content with an often dangerous speed. This can render the drinker more vulnerable to alcohol-related brain damage. In addition, alcohol abuse can have a detrimental impact on hydration and the body's retention of minerals and nutrients, further exacerbating the consequences of malnutrition and denigrating an individual's cognitive faculties. This can ultimately have a negative impact on academic performance.

These harmful consequences can be more easily induced in women, as women are oftentimes less capable of metabolizing alcohol than men. On CBS News, Carrie Wilkins, PhD, of the Center for Motivation and Change (a private practice group based in New York City) describes how women are more vulnerable to particular toxic side effects of alcohol consumption.

Drunkorexia can lead to short term and long term cognitive problems including difficulty concentrating and difficulty making decisions. It also increases the risk of developing more serious eating disorders or alcohol abuse problems. As binge drinking is involved there is a greater risk for violence, risky sexual behavior, alcohol poisoning, substance abuse and chronic disease later in life.

There are many health hazards that are caused from drinking. When students drink too much, the alcohol affects one's brain and ability to comprehend what is going on. One such problem is alcohol poisoning. After drinking too much, the alcohol and toxins in alcoholic drinks cause complications in one's brain and respiratory system. This causes mental and physical issues in one's body and could be very dangerous for one's health. Other hazardous health issues could arise from a drug called Rohypnol, nicknamed roofies. This is a toxic drug that could potentially be slipped into one’s drink which cause one to lose sight of what one thinks and does. This will also cause complications within one's body.

A legal minimum age for the buying or consuming of alcohol is in place in many of the world's countries, typically with the intent to protect the young from alcohol-related harm. This age varies between countries; for example, the minimum legal drinking age for Australia is 18, whereas the MLDA in the United States is 21.

Drunkorexia consists of 3 major aspects: alcohol use/abuse, food intake restriction, and excessive physical activity. It is commonly summarised in the following activities:

- Counting daily calorie intake (commonly known as "calorie counting") to ensure no weight will be gained when consuming alcohol.

- Missing or skipping meals to conserve calories for consumption of alcoholic beverages.

- Over exercising to counterweigh for calories consumed from alcoholic beverages.

- Consuming an extreme amount of alcohol to vomit previously digested food.

As demonstrated by the chart below, numerous studies have examined factors which mediate substance abuse or dependence. In these examples, the predictor variables lead to the mediator which in turn leads to the outcome, which is always substance abuse or dependence. For example, research has found that being raised in a single-parent home can lead to increased exposure to stress and that increased exposure to stress, not being raised in a single-parent home, leads to substance abuse or dependence. The following are some, but by no means all, of the possible mediators of substance abuse.

As demonstrated by the chart below, numerous studies have examined factors which moderate substance abuse or dependence. In these examples, the moderator variable impacts the level to which the strength of the relationship varies between a given predictor variable and the outcome of substance abuse or dependence. For example, there is a significant relationship between psychobehavioral risk factors, such as tolerance of deviance, rebelliousness, achievement, perceived drug risk, familism, family church attendance and other factors, and substance abuse and dependence. That relationship is moderated by familism which means that the strength of the relationship is increased or decreased based on the level of familism present in a given individual.

Examples of mediators and moderators can be found in several empirical studies. For example, Pilgrim et al.’s hypothesized mediation model posited that school success and time spent with friends mediated the relationship between parental involvement and risk-taking behavior with substance use (2006). More specifically, the relationship between parental involvement and risk-taking behavior is explained via the interaction with third variables, school success and time spent with friends. In this example, increased parental involvement led to increased school success and decreased time with friends, both of which were associated with decreased drug use. Another example of mediation involved risk-taking behaviors. As risk-taking behaviors increased, school success decreased and time with friends increased, both of which were associated with increased drug use.

A second example of a mediating variable is depression. In a study by Lo and Cheng (2007), depression was found to mediate the relationship between childhood maltreatment and subsequent substance abuse in adulthood. In other words, childhood physical abuse is associated with increased depression, which in turn, in associated with increased drug and alcohol use in young adulthood. More specifically, depression helps to explain how childhood abuse is related to subsequent substance abuse in young adulthood.

A third example of a mediating variable is an increase of externalizing symptoms. King and Chassin (2008) conducted research examining the relationship between stressful life events and drug dependence in young adulthood. Their findings identified problematic externalizing behavior on subsequent substance dependency. In other words, stressful life events are associated with externalizing symptoms, such as aggression or hostility, which can lead to peer alienation or acceptance by socially deviant peers, which could lead to increased drug use. The relationship between stressful life events and subsequent drug dependence however exists via the presence of the mediation effects of externalizing behaviors.

An example of a moderating variable is level of cognitive distortion. An individual with high levels of cognitive distortion might react adversely to potentially innocuous events, and may have increased difficulty reacting to them in an adaptive manner (Shoal & Giancola, 2005). In their study, Shoal and Giancola investigated the moderating effects of cognitive distortion on adolescent substance use. Individuals with low levels of cognitive distortion may be more apt to choose more adaptive methods of coping with social problems, thereby potentially reducing the risk of drug use. Individuals with high levels of cognitive distortions, because of their increased misperceptions and misattributions, are at increased risk for social difficulties. Individuals may be more likely to react aggressively or inappropriately, potentially alienating themselves from their peers, thereby putting them at greater risk for delinquent behaviors, including substance use and abuse. In this study, social problems are a significant risk factor for drug use when moderated by high levels of cognitive distortions.

Dark cell degeneration as well as inhibition of brain neural stem cell proliferation and neurogenesis are among the causes of alcohol related brain damage. Increases in microglia density also occurs in alcohol abusers which is evidence of neurodegeneration. These increases in microglia persist after abstinence from alcohol according to animal research. People with an alcohol use disorder also show an increased expression of proinflammatory cytokine and microglia protein expression.

Adolescents are naturally at increased risk of alcohol abuse due to increased impulsivity and sensation seeking which results in larger intake of alcohol and more frequent binge drinking episodes. Additionally the developing brain of adolescents is significantly more vulnerable to the neurotoxic and neurodegenerative effects of alcohol abuse. It also appears that there is a genetic risk for proinflammatory cytokine mediated alcohol-related brain damage. There is evidence that variants of these genes are involved not only in contributing to brain damage but also to impulsivity and alcohol abuse and all three of these genetic traits contribute heavily to an alcohol use disorder.

Some medical systems, including those of at least 15 states of the United States, refer to an Addiction Severity Index to assess the severity of problems related to substance use. According to DARA Thailand, the index assesses potential problems in seven categories: medical, employment/support, alcohol, other drug use, legal, family/social, and psychiatric.