The Alcohol Use Disorders Identification Test (AUDIT) is considered the most accurate alcohol screening tool for identifying potential alcohol misuse, including dependence. It was developed by the World Health Organisation, designed initially for use in primary healthcare settings with supporting guidance.

The Severity of Alcohol Dependence Questionnaire (SADQ or SAD-Q) is a 20 item clinical screening tool designed to measure the presence and level of alcohol dependence.

The Alcohol Use Disorders Identification Test (AUDIT) is considered the most accurate alcohol screening tool for identifying potential alcohol misuse, including dependence. It was developed by the World Health Organisation, designed initially for use in primary healthcare settings with supporting guidance.

Different countries recommend different maximum quantities. For most countries, the maximum quantity for men is 140 g–210 g per week. For women, the range is 84 g–140 g per week. Most countries recommend total abstinence during pregnancy and lactation.

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.

Preventing or reducing the harm has been called for via increased taxation of alcohol, stricter regulation of alcohol advertising and the provision of brief Interventions. Brief Interventions for alcohol abuse reduce the incidence of unsafe sex, sexual violence, unplanned pregnancy and, likely, STD transmission. Information and education on social norms and the harms associated with alcohol abuse delivered via the internet or face-to-face has not been found to result in any meaningful benefit in changing harmful drinking behaviours in young people.

According to European law, individuals who are suffering from alcohol abuse or other related problems cannot be given a license, or if in possession of a license cannot get it renewed. This is a way to prevent individuals driving under the influence of alcohol, but does not prevent alcohol abuse per se.

An individual's need for alcohol can depend on their family's alcohol use history. For instance, if it is discovered that their family history with alcohol has a strong pattern, there might be a need for education to be set in place to reduce the likelihood of reoccurrence (Powers, 2007). However, studies have established that those with alcohol abuse tend to have family members who try to provide help. In many of these occasions the family members would try to help the individual to change or to help improve the individual's lifestyle.

There are several different screening tools that have been validated for use with adolescents such as the CRAFFT Screening Test and in adults the CAGE questionnaire.

Some recommendations for screening tools for substance misuse in pregnancy include that they take less than 10 minutes, should be used routinely, include an educational component. Tools suitable for pregnant women include i.a. 4Ps, T-ACE, TWEAK, TQDH (Ten-Question Drinking History), and AUDIT.

Many hospitals use the Clinical Institute Withdrawal Assessment for Alcohol (CIWA) protocol in order to assess the level of withdrawal present and therefore the amount of medication needed. When overuse of alcohol is suspected but drinking history is unclear, testing for elevated values of carbohydrate-deficient transferrin or gammaglutamyl transferase can help make the diagnosis of alcohol overuse and dependence more clear. The CIWA has also been shortened (now called the CIWA-Ar), while retaining its validity and reliability, to help assess patients more efficiently due to the life-threatening nature of alcohol withdrawal.

Other conditions that may present similarly include benzodiazepine withdrawal syndrome (a condition also mainly caused by GABA receptor adaptation).

The World Health Organization, the European Union and other regional bodies, national governments and parliaments have formed alcohol policies in order to reduce the harm of alcoholism. Targeting adolescents and young adults is regarded as an important step to reduce the harm of alcohol abuse. Increasing the age at which licit drugs of abuse such as alcohol can be purchased, the banning or restricting advertising of alcohol has been recommended as additional ways of reducing the harm of alcohol dependence and abuse. Credible, evidence based educational campaigns in the mass media about the consequences of alcohol abuse have been recommended. Guidelines for parents to prevent alcohol abuse amongst adolescents, and for helping young people with mental health problems have also been suggested.

There are reliable tests for the actual use of alcohol, one common test being that of blood alcohol content (BAC). These tests do not differentiate alcoholics from non-alcoholics; however, long-term heavy drinking does have a few recognizable effects on the body, including:

- Macrocytosis (enlarged MCV)

- Elevated GGT

- Moderate elevation of AST and ALT and an AST: ALT ratio of 2:1

- High carbohydrate deficient transferrin (CDT)

With regard to alcoholism, BAC is useful to judge alcohol tolerance, which in turn is a sign of alcoholism.

However, none of these blood tests for biological markers is as sensitive as screening questionnaires.

Cannabis use disorder is recognized in the fifth version of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5), which added cannabis withdrawal as a new condition. In the United States, the average adult who seeks treatment has consumed cannabis for over 10 years almost daily and has actively attempted to quit six or more times.

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.

For a diagnosis of benzodiazepine dependence to be made, the ICD-10 requires that at least 3 of the below criteria are met and that they have been present for at least a month, or, if less than a month, that they appeared repeatedly during a 12-month period.

- Behavioral, cognitive, and physiological phenomena that are associated with the repeated use and that typically include a strong desire to take the drug.

- Difficulty controlling use

- Continued use despite harmful consequences

- Preference given to drug use rather than to other activities and obligations

- Increased tolerance to effects of the drug and sometimes a physical withdrawal state.

These diagnostic criteria are good for research purposes, but, in everyday clinical practice, they should be interpreted according to clinical judgement. In clinical practice, benzodiazepine dependence should be suspected in those having used benzodiazepines for longer than a month, in particular, if they are from a high-risk group. The main factors associated with an increased incidence of benzodiazepine dependence include:

- Dose

- Duration

- Concomitant use of antidepressants

Benzodiazepine dependence should be suspected also in individuals having substance use disorders including alcohol, and should be suspected in individuals obtaining their own supplies of benzodiazepines. Benzodiazepine dependence is almost certain in individuals who are members of a tranquilizer self-help group.

Research has found that about 40 percent of people with a diagnosis of benzodiazepine dependence are not aware that they are dependent on benzodiazepines, whereas about 11 percent of people judged not to be dependent believe that they are.

When assessing a person for benzodiazepine dependence, asking specific questions rather than questions based on concepts is recommended by experts as the best approach of getting a more accurate diagnosis. For example, asking persons if they "think about the medication at times of the day other than when they take the drug" would provide a more meaningful answer than asking "do you think you are psychologically dependent?". The Benzodiazepine Dependence Self Report Questionnaire is one questionnaire used to assess and diagnose benzodiazepine dependence.

Over-consumption of alcohol causes many deaths worldwide. The overall mortality from alcohol use was found to be similar to that of the effect of physical inactivity. A review in 2009 found that "the net effect of alcohol consumption on health is detrimental, with an estimated 3.8% of all global deaths and 4.6% of global disability-adjusted life-years attributable to alcohol."

Extensive research of Western cultures has consistently shown increased survival associated with light to moderate alcohol consumption. A 23-year prospective study of 12,000 male British physicians aged 48–78, found that overall mortality was significantly lower in current drinkers compared to non-drinkers even after correction for ex-drinkers. This benefit was strongest for ischemic heart disease, but was also noted for other vascular disease and respiratory disease. Death rate amongst current drinkers was higher for 'alcohol augmentable' disease such as liver disease and oral cancers, but these deaths were much less common than cardiovascular and respiratory deaths. The lowest mortality rate was found for consumption of 8 to 14 'units' per week. In the UK a unit is defined as 10ml or 8g of pure alcohol. Higher consumption increased overall mortality rate, but not above that of non-drinkers. Other studies have found age-dependent mortality risks of low-to-moderate alcohol use: an increased risk for individuals aged 16–34 (due to increased risk of cancers, accidents, liver disease, and other factors), but a decreased risk for individuals ages 55+ (due to lower incidence of ischemic heart disease).

This is consistent with other research that found a J-curve dependency between alcohol consumption and total mortality among middle aged and older men. While the mortality rates of ex-drinkers and heavy drinkers are significantly elevated, the all-cause mortality rates may be 15-18% lower among moderate drinkers. Although the definition of a drink varies between studies and countries, this meta-analysis found that low levels of alcohol intake, defined as 1-2 drinks per day for women and 2-4 drinks per day for men, was associated with lower mortality than abstainers. This claim was challenged by another study that found that in certain low quality studies occasional drinkers or ex-drinkers were included as abstainers, resulting in the increased mortality in that group. However, the J-curve for total and CHD mortality was reconfirmed by studies that took the mentioned confounders into account. There seems to be little discussion of what proportion of individuals classified as abstainers are those already at greater risk of mortality due to chronic conditions and do not or cannot consume alcohol for reasons of health or harmful interactions with medication.

The observed decrease in mortality of light-to-moderate drinkers compared to never drinkers might be partially explained by superior health and social status of the drinking group; however, the protective effect of alcohol in light to moderate drinkers remains significant even after adjusting for these confounders. Additionally, confounders such as underreporting of alcohol intake might lead to the underestimation of how much mortality is reduced in light-to-moderate drinkers.

A 2010 study confirmed the beneficial effect of moderate alcohol consumption on mortality. Subjects were grouped into abstainers, light, moderate, and heavy drinkers. The order of mortality rates from lowest to highest were moderate, light, heavy, and abstainers. The increased risk for abstainers was twice the mortality rate as for moderate drinkers. This study specifically sought to control for confounding factors including the problem of ex-drinkers considered as non-drinkers. According to another study, drinkers with heavy drinking occasions (six or more drinks at a time) have a 57% higher all-cause mortality than drinkers without heavy drinking occasions.

Mortality is lowest among young abstainers and highest among young heavy drinkers.

In contrast to studies of Western cultures, research in other cultures has yielded some opposite findings. The landmark INTERHEART Study has revealed that alcohol consumption in South Asians was not protective against CAD in sharp contrast to other populations who benefit from it. In fact Asian Indians who consume alcohol had a 60% higher risk of heart attack which was greater with local spirits (80%) than branded spirits (50%). The harm was observed in alcohol users classified as occasional as well as regular light, moderate, and heavy consumers.

Another large study of 4465 subjects in India also confirmed the possible harm of alcohol consumption on coronary risk in men. Compared to lifetime abstainers, alcohol users had higher blood sugar (2 mg/dl), blood pressure (2 mm Hg) levels, and the HDL-C levels (2 mg/dl) and significantly higher tobacco use (63% vs. 21%).

Many countries collect statistics on alcohol-related deaths. While some categories relate to short-term effects, such as accidents, many relate to long-term effects of alcohol.

Young people are at greater risk of developing cannabis dependency because of the association between early initiation into substance use and subsequent problems such as dependence, and the risks associated with using cannabis at a developmentally vulnerable age. In addition there is evidence that cannabis use during adolescence, at a time when the brain is still developing, may have deleterious effects on neural development and later cognitive functioning.

Benzodiazepines are effective for the management of symptoms as well as the prevention of seizures. Certain vitamins are also an important part of the management of alcohol withdrawal syndrome. In those with severe symptoms inpatient care is often required. In those with lesser symptoms treatment at home may be possible with daily visits with a health care provider.

It is common for individuals with drugs use disorder to have other psychological problems. The terms “dual diagnosis” or “co-occurring disorders,” refer to having a mental health and substance use disorder at the same time. According to the British Association for Psychopharmacology (BAP), “symptoms of psychiatric disorders such as depression, anxiety and psychosis are the rule rather than the exception in patients misusing drugs and/or alcohol.”

Individuals who have a comorbid psychological disorder often have a poor prognosis if either disorder is untreated. Historically most individuals with dual diagnosis either received treatment only for one of their disorders or they didn’t receive any treatment all. However, since the 1980s, there has been a push towards integrating mental health and addiction treatment. In this method, neither condition is considered primary and both are treated simultaneously by the same provider.

The tolerance to alcohol is not equally distributed throughout the world's population, and genetics of alcohol dehydrogenase indicate resistance has arisen independently in different cultures. In North America, Native Americans have the highest probability of developing alcoholism compared to Europeans and Asians.

Higher body masses and the prevalence of high levels of alcohol dehydrogenase in an individual increase alcohol tolerance.

Not all differences in tolerance can be traced to biochemistry. Differences in tolerance levels are also influenced by socio-economic and cultural difference including diet, average body weight and patterns of consumption.

An estimated one out of twenty people have an alcohol flush reaction. It is not in any way an indicator for the drunkenness of an individual. It is colloquially known as "face flush", a condition where the body metabolizes alcohol nearly 100-times less efficiently into acetaldehyde, a toxic metabolite. Flushing, or blushing, is associated with the erythema (reddening caused by dilation of capillaries) of the face, neck, and shoulder, after consumption of alcohol.

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.

Benzodiazepines are regarded as a highly addictive drug class. A psychological and physical dependence can develop in as short as a few weeks but may take years to develop in other individuals. Patients wanting to withdraw from benzodiazepines typically receive little advice or support, and such withdrawal should be by small increments over a period of months.

Benzodiazepines are usually prescribed only short-term, as there is little justification for their prescribing long-term. Some doctors however, disagree and believe long-term use beyond 4 weeks is sometimes justified, although there is little data to support this viewpoint. Such viewpoints are a minority in the medical literature.

There is no evidence that "drug holidays" or periods of abstinence reduced the risk of dependence; there is evidence from animal studies that such an approach does not prevent dependence from happening. Use of short-acting benzodiazepines is associated with interdose withdrawal symptoms. Kindling has clinical relevance with regard to benzodiazepines; for example, there is an increasing shift to use of benzodiazepines with a shorter half-life and intermittent use, which can result in interdose withdrawal and rebound effects.

Problem benzodiazepine use can be associated with various deviant behaviors, including drug-related crime. In a survey of police detainees carried out by the Australian Government, both legal and illegal users of benzodiazepines were found to be more likely to have lived on the streets, less likely to have been in full-time work and more likely to have used heroin or methamphetamines in the past 30 days from the date of taking part in the survey. Benzodiazepine users were also more likely to be receiving illegal incomes and more likely to have been arrested or imprisoned in the previous year. Benzodiazepines were sometimes reported to be used alone, but most often formed part of a poly drug-using problem. Female users were more likely than men to be using heroin, whereas male users were more likely to report amphetamine use. Benzodiazepine users were more likely than non-users to claim government financial benefits and benzodiazepine users who were also poly-drug users were the most likely to be claiming government financial benefits. Those who reported using benzodiazepines alone were found to be in the mid-range when compared to other drug using patterns in terms of property crimes and criminal breaches. Of the detainees reporting benzodiazepine use, one in five reported injection use, mostly of illicit temazepam, with some who reported injecting prescribed benzodiazepines. The injection was a concern in this survey due to increased health risks. The main problems highlighted in this survey were concerns of dependence, the potential for overdose of benzodiazepines in combination with opiates and the health problems associated with injection of benzodiazepines.

Benzodiazepines are also sometimes used for drug facilitated sexual assaults and robbery, however, alcohol remains the most common drug involved in drug facilitated assaults. The muscle relaxant, disinhibiting and amnesia producing effects of benzodiazepines are the pharmacological properties which make these drugs effective in drug-facilitated crimes. Serial killer Jeffrey Dahmer admitted to using triazolam (Halcion), and occasionally temazepam (Restoril), in order to sedate his victims prior to murdering them.

In a 2017 publication, an analysis of the blood samples of 22 victims of drug-facilitated robberies in Bangladesh revealed that criminals use different mixtures of Benzodiazepines including Lorazepam, Midazolam, Diazepam and Nordiazepam to immobilize and then rob their victims.

Alcohol tolerance is increased by regular drinking. This reduced sensitivity requires that higher quantities of alcohol be consumed in order to achieve the same effects as before tolerance was established. Alcohol tolerance may lead to (or be a sign of) alcohol dependency.

Heavy alcohol consumption over a period of years can lead to "reverse tolerance". A liver can be damaged by chronic alcohol use, leading to a buildup of fat and scar tissue. The reduced ability of such a liver to metabolize or break down alcohol means that small amounts can lead to a high blood alcohol concentration (BAC) and more rapid intoxication.

According to the British National Formulary, it is better to withdraw too slowly rather than too quickly from benzodiazepines. The rate of dosage reduction is best carried out so as to minimize the symptoms' intensity and severity. Anecdotally, a slow rate of reduction may reduce the risk of developing a severe protracted syndrome.

Long half-life benzodiazepines like diazepam or chlordiazepoxide are preferred to minimize rebound effects and are available in low potency dose forms. Some people may not fully stabilize between dose reductions, even when the rate of reduction is slowed. Such people sometimes simply need to persist as they may not feel better until they have been fully withdrawn from them for a period of time.

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.

The diagnosis of benzodiazepine overdose may be difficult, but is usually made based on the clinical presentation of the patient along with a history of overdose. Obtaining a laboratory test for benzodiazepine blood concentrations can be useful in patients presenting with CNS depression or coma of unknown origin. Techniques available to measure blood concentrations include thin layer chromatography, gas liquid chromatography with or without a mass spectrometer, and radioimmunoassay. Blood benzodiazepine concentrations, however, do not appear to be related to any toxicological effect or predictive of clinical outcome. Blood concentrations are, therefore, used mainly to confirm the diagnosis rather than being useful for the clinical management of the patient.