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).

Definitive diagnosis relies on a blood test for alcohol, usually performed as part of a toxicology screen.

Law enforcement officers in the United States of America often use breathalyzer units and field sobriety tests as more convenient and rapid alternatives to blood tests.

There are also various models of breathalyzer units that are available for consumer use. Because these may have varying reliability and may produce different results than the tests used for law-enforcement purposes, the results from such devices should be conservatively interpreted.

Many informal intoxication tests exist, which, in general, are unreliable and not recommended as deterrents to excessive intoxication or as indicators of the safety of activities such as motor vehicle driving, heavy equipment operation, machine tool use, etc.

For determining whether someone is intoxicated by alcohol by some means other than a blood-alcohol test, it is necessary to rule out other conditions such as hypoglycemia, stroke, usage of other intoxicants, mental health issues, and so on. It is best if his/her behavior has been observed while the subject is sober to establish a baseline. Several well-known criteria can be used to establish a probable diagnosis. For a physician in the acute-treatment setting, acute alcohol intoxication can mimic other acute neurological disorders, or is frequently combined with other recreational drugs that complicate diagnosis and treatment.

Diagnosis is mainly based on symptoms. In a person with delirium tremens it is important to rule out other associated problems such as electrolyte abnormalities, pancreatitis, and alcoholic hepatitis.

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.

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.

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.

The substance that has been taken may often be determined by asking the person. However, if they will not, or cannot, due to an altered level of consciousness, provide this information, a search of the home or questioning of friends and family may be helpful.

Examination for toxidromes, drug testing, or laboratory test may be helpful. Other laboratory test such as glucose, urea and electrolytes, paracetamol levels and salicylate levels are typically done. Negative drug-drug interactions have sometimes been misdiagnosed as an acute drug overdose, occasionally leading to the assumption of suicide.

In general, the simultaneous use of multiple drugs should be carefully monitored by a qualified individual such as board certified and licensed medical doctor, either an MD or DO Close association between prescribing physicians and pharmacies, along with the computerization of prescriptions and patients' medical histories, aim to avoid the occurrence of dangerous drug interactions. Lists of contraindications for a drug are usually provided with it, either in monographs, package inserts (accompanying prescribed medications), or in warning labels (for OTC drugs). CDI/MDI might also be avoided by physicians requiring their patients to return any unused prescriptions. Patients should ask their doctors and pharmacists if there are any interactions between the drugs they are taking.

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.

Examples (and ICD-10 code) include:

- F10.0 alcohol intoxication

- F11.0 opioid intoxication

- F12.0 cannabinoid intoxication

- F13.0 sedative and hypnotic intoxication (see benzodiazepine overdose and barbiturate overdose)

- F14.0 cocaine intoxication

- F15.0 caffeine intoxication

- F16.0 hallucinogen intoxication (See for example Lysergic acid diethylamide effects)

- F17.0 tobacco intoxication

The term contact high is sometimes used to describe intoxication without direct administration, either by second-hand smoke as with cannabis, or by placebo in the presence of others who are high.

People who engage in polypharmacy and other hypochondriac behaviors are at an elevated risk of death from CDI. Elderly people are at the highest risk of CDI, because of having many age-related health problems requiring many medications combined with age-impaired judgment, leading to confusion in taking medications.

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.

Substance intoxication is a type of substance use disorder which is potentially maladaptive and impairing, but reversible, and associated with recent use.

If the symptoms are severe, the term "substance intoxication delirium" may be used.

Generic slang terms include: getting high or being stoned or blazed (all usually in reference to cannabis), with many more specific slang terms for each particular type of intoxicant. Alcohol intoxication is even graded in intensity, from buzzed, to tipsy, all the way up to hammered, smashed, wasted, destroyed, and a number of other similar terms.

A normal liver detoxifies the blood of alcohol over a period of time that depends on the initial level and the patient's overall physical condition. An abnormal liver will take longer but still succeeds, provided the alcohol does not cause liver failure.

People having drunk heavily for several days or weeks may have withdrawal symptoms after the acute intoxication has subsided.

A person consuming a dangerous amount of alcohol persistently can develop memory blackouts and idiosyncratic intoxication or pathological drunkenness symptoms.

Long-term persistent consumption of excessive amounts of alcohol can cause liver damage and have other deleterious health effects.

In general, alcohol abusers with withdrawal symptoms, such as alcoholic hallucinosis, have a deficiency of several vitamins and minerals and their bodies could cope with the withdrawal easier by taking nutritional supplements. Alcohol abuse can create a deficiency of thiamine, magnesium, zinc, folate and phosphate as well as cause low blood sugar. However, several tested drugs have shown the disappearance of hallucinations. Neuroleptics and benzodiazepines showed normalization. Common benzodiazepines are chlordiazepoxide and lorazepam. It has been shown that management has been effective with a combination of abstinence from alcohol and the use of neuroleptics. It is also possible to treat withdrawal before major symptoms start to happen in the body. Diazepam and chlordiazepoxide have proven to be effective in treating alcohol withdrawal symptoms such as alcoholic halluciniosis. With the help of these specific medications, the process of withdrawal is easier to go through, making alcoholic hallucinosis less likely to occur.

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.

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.

Delirium tremens due to alcohol withdrawal can be treated with benzodiazepines. High doses may be necessary to prevent death. Amounts given are based on the symptoms. Typically the person is kept sedated with benzodiazepines, such as diazepam, lorazepam, chlordiazepoxide, or oxazepam.

In some cases antipsychotics, such as haloperidol may also be used. Older drugs such as paraldehyde and clomethiazole were formerly the traditional treatment but have now largely been superseded by the benzodiazepines.

Acamprosate is occasionally used in addition to other treatments, and is then carried on into long term use to reduce the risk of relapse. If status epilepticus occurs it is treated in the usual way. It can also be helpful to control environmental stimuli, by providing a well-lit but relaxing environment for minimizing distress and visual hallucinations.

Alcoholic beverages can also be prescribed as a treatment for delirium tremens, but this practice is not universally supported.

High doses of thiamine often by the intravenous route is also recommended.

Alcoholic hallucinosis (or alcohol-related psychosis or alcohol-induced psychotic disorder) is a complication of alcohol withdrawal in alcoholics. Descriptions of the condition date back to at least 1907. They can occur during acute intoxication or withdrawal with the potential of having delirium tremens. Alcohol hallucinosis is a rather uncommon alcohol-induced psychotic disorder only being seen in chronic alcoholics who have many consecutive years of severe and heavy drinking during their lifetime. Alcoholic hallucinosis develops about 12 to 24 hours after the heavy drinking stops suddenly, and can last for days. It involves auditory and visual hallucinations, most commonly accusatory or threatening voices. The risk of developing alcoholic hallucinosis is increased by long-term heavy alcohol abuse and the use of other drugs.

The distribution of naloxone to injection drug users and other opioid drug users decreases the risk of death from overdose. The Centers for Disease Control and Prevention (CDC) estimates that U.S. programs for drug users and their caregivers prescribing take-home doses of naloxone and training on its utilization are estimated to have prevented 10,000 opioid overdose deaths. Healthcare institution-based naloxone prescription programs have also helped reduce rates of opioid overdose in the U.S. state of North Carolina, and have been replicated in the U.S. military. Nevertheless, scale-up of healthcare-based opioid overdose interventions is limited by providers' insufficient knowledge and negative attitudes towards prescribing take-home naloxone to prevent opioid overdose. Programs training police and fire personnel in opioid overdose response using naloxone have also shown promise in the US.

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.

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.

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.

Caffeine is used in:

- Bronchopulmonary dysplasia in premature infants for both prevention and treatment. It may improve weight gain during therapy and reduce the incidence of cerebral palsy as well as reduce language and cognitive delay. On the other hand, subtle long-term side effects are possible.

- Apnea of prematurity as a primary treatment, but not prevention.

- Orthostatic hypotension treatment.

Medical observation and supportive care are the mainstay of treatment of benzodiazepine overdose. Although benzodiazepines are absorbed by activated charcoal, gastric decontamination with activated charcoal is not beneficial in pure benzodiazepine overdose as the risk of adverse effects would outweigh any potential benefit from the procedure. It is recommended only if benzodiazepines have been taken in combination with other drugs that may benefit from decontamination. Gastric lavage (stomach pumping) or whole bowel irrigation are also not recommended. Enhancing elimination of the drug with hemodialysis, hemoperfusion, or forced diuresis is unlikely to be beneficial as these procedures have little effect on the clearance of benzodiazepines due to their large volume of distribution and lipid solubility.