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.

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.

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.

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.

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.

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.

Addiction is a complex but treatable condition. It is characterized by compulsive drug craving, seeking, and use that persists even if the user is aware of severe adverse consequences. For some people, addiction becomes chronic, with periodic relapses even after long periods of abstinence. As a chronic, relapsing disease, addiction may require continued treatments to increase the intervals between relapses and diminish their intensity. While some with substance issues recover and lead fulfilling lives, others require ongoing additional support. The ultimate goal of addiction treatment is to enable an individual to manage their substance misuse; for some this may mean abstinence. Immediate goals are often to reduce substance abuse, improve the patient's ability to function, and minimize the medical and social complications of substance abuse and their addiction; this is called "harm reduction".

Treatments for addiction vary widely according to the types of drugs involved, amount of drugs used, duration of the drug addiction, medical complications and the social needs of the individual. Determining the best type of recovery program for an addicted person depends on a number of factors, including: personality, drugs of choice, concept of spirituality or religion, mental or physical illness, and local availability and affordability of programs.

Many different ideas circulate regarding what is considered a successful outcome in the recovery from addiction. Programs that emphasize controlled drinking exist for alcohol addiction. Opiate replacement therapy has been a medical standard of treatment for opioid addiction for many years.

Treatments and attitudes toward addiction vary widely among different countries. In the US and developing countries, the goal of commissioners of treatment for drug dependence is generally total abstinence from all drugs. Other countries, particularly in Europe, argue the aims of treatment for drug dependence are more complex, with treatment aims including reduction in use to the point that drug use no longer interferes with normal activities such as work and family commitments; shifting the addict away from more dangerous routes of drug administration such as injecting to safer routes such as oral administration; reduction in crime committed by drug addicts; and treatment of other comorbid conditions such as AIDS, hepatitis and mental health disorders. These kinds of outcomes can be achieved without eliminating drug use completely. Drug treatment programs in Europe often report more favorable outcomes than those in the US because the criteria for measuring success are functional rather than abstinence-based. The supporters of programs with total abstinence from drugs as a goal believe that enabling further drug use means prolonged drug use and risks an increase in addiction and complications from addiction.

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.

"Substance dependence", as defined in the DSM, can be diagnosed with physiological dependence, evidence of tolerance or withdrawal, or without physiological dependence.

DSM-5 substance dependencies include:

- 303.90 Alcohol dependence

- 304.00 Opioid dependence

- 304.10 Sedative, hypnotic, or anxiolytic dependence (including benzodiazepine dependence and barbiturate dependence)

- 304.20 Cocaine dependence

- 304.30 Cannabis dependence

- 304.40 Amphetamine dependence (or amphetamine-like)

- 304.50 Hallucinogen dependence

- 304.60 Inhalant dependence

- 304.80 Polysubstance dependence

- 304.90 Phencyclidine (or phencyclidine-like) dependence

- 304.90 Other (or unknown) substance dependence

- 305.10 Nicotine dependence

Therapists often classify patients with chemical dependencies as either interested or not interested in changing.

Treatments usually involve planning for specific ways to avoid the addictive stimulus, and therapeutic interventions intended to help a client learn healthier ways to find satisfaction. Clinical leaders in recent years have attempted to tailor intervention approaches to specific influences that affect addictive behavior, using therapeutic interviews in an effort to discover factors that led a person to embrace unhealthy, addictive sources of pleasure or relief from pain.

From the applied behavior analysis literature and the behavioral psychology literature, several evidenced-based intervention programs have emerged (1) behavioral marital therapy (2) community reinforcement approach (3) cue exposure therapy and (4) contingency management strategies. In addition, the same author suggests that social skills training adjunctive to inpatient treatment of alcohol dependence is probably efficacious.

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.

Amphetamine dependence refers to a state of psychological dependence on a drug in the amphetamine class. In individuals with substance use disorder (problematic use or abuse with dependence), psychotherapy is currently the best treatment option as no pharmacological treatment has been approved. Tolerance is expected to develop with regular substituted amphetamine use. When substituted amphetamines are abused, drug tolerance develops rapidly.

Severe withdrawal associated with dependence from recreational substituted amphetamine use can be difficult for a user to cope with. Long-term use of certain substituted amphetamines, particularly methamphetamine, can reduce dopamine activity in the brain. Psychostimulants that increase dopamine and mimic the effects of substituted amphetamines, but with lower abuse liability, could theoretically be used as replacement therapy in amphetamine dependence. However, the few studies that used amphetamine, bupropion, methylphenidate and modafinil as a replacement therapy did not result in less methamphetamine use or craving.

In 2013, overdose on amphetamine, methamphetamine, and other compounds implicated in an "amphetamine use disorder" resulted in an estimated 3,788 deaths worldwide (3,425–4,145 deaths, 95% confidence).

The symptoms of stimulant use disorder include failure to control usage and frequency of use, an intense craving for the drug, increased use over time to obtain the same effects, known as a developed tolerance, and a continued use despite negative repercussions and interference in one’s everyday life and functioning. Furthermore, a disorder is noted when withdrawal symptoms occur because of a decrease in the drug amount and frequency, as well as stopping the use of the drug entirely. These withdrawal symptoms can last for days, weeks, months, and on rare occasions, years, depending on the frequency and dosages used by the individual. These symptoms include, but are not limited to, increased appetite, decreased energy, depression, loss of motivation and interest in once pleasurable activities, anxiety, insomnia, agitation and an intense craving for the drug. Unless intensive medical and psychological treatment is sought after, there is a very high likelihood of relapse among the user.

Barbiturate dependence develops with regular use of barbiturates. This in turn may lead to a need for increasing doses of the drug to get the original desired pharmacological or therapeutic effect. Barbiturate use can lead to both addiction and physical dependence, and as such they have a high potential for abuse. Management of barbiturate dependence involves considering the affected person's age, comorbidity and the pharmacological pathways of barbiturates. Psychological addiction to barbiturates can develop quickly. The GABA receptor, one of barbiturates' main sites of action, is thought to play a pivotal role in the development of tolerance to and dependence on barbiturates, as well as the euphoric "high" that results from their abuse. The mechanism by which barbiturate tolerance develops is believed to be different from that of ethanol or benzodiazepines, even though these drugs have been shown to exhibit cross-tolerance with each other. The management of a physical dependence on barbiturates is stabilisation on the long-acting barbiturate phenobarbital followed by a gradual titration down of dose. The slowly eliminated phenobarbital lessens the severity of the withdrawal syndrome and reduces the chances of serious barbiturate withdrawal effects such as seizures. Antipsychotics are not recommended for barbiturate withdrawal (or other CNS depressant withdrawal states) especially clozapine, olanzapine or low potency phenothiazines e.g. chlorpromazine as they lower the seizure threshold and can worsen withdrawal effects; if used extreme caution is required.

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.

The long-term abuse of stimulants ultimately causes very serious medical issues, including but not limited to, addiction. Addiction, which is a disease that causes high rates of relapse, can be defined as a chronic disease that is characterized as a compulsive drug seeking behavior in which the user will stop at nothing to obtain the drug. Long time users of stimulants have noted changes in the body such as brain function, chemistry and molecular or cellular adaptations.

The more recently published DSM-5 combined substance abuse and substance dependence into a single continuum; this is simply known as substance use disorder and requires more presenting symptoms before a diagnosis is made. It also considers each different substance as its own separate disorder, based upon the same basic criteria. It also distinguishes the difference between dependence and addictions as two separate disorders, not to be confused.

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.

Substance-induced disorders include medical conditions that can be directly attributed to the use of a substance. These conditions include intoxication, withdrawal, substance-induced delirium, substance-induced psychosis, and substance-induced mood disorders.

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.

Substance use disorders can be confused with other psychiatric disorders. There are diagnoses for substance-induced mood disorders and substance-induced anxiety disorders and thus such overlap can be complicated. For this reason, the DSM-IV advises that diagnoses of primary psychiatric disorders not be made in the absence of sobriety (of duration sufficient to allow for any substance-induced post-acute-withdrawal symptoms to dissipate) up to 1 year.

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.

Comorbidity of addictive disorders and other psychiatric disorders, i.e., dual disorders, is very common and a large body of literature has accumulated demonstrating that mental disorders are strongly associated with substance use disorders. The 2011 USA National Survey on Drug Use and Health found that 17.5% of adults with a mental illness had a co-occurring substance use disorder; this works out to 7.98 million people. Estimates of co-occurring disorders in Canada are even higher, with an estimated 40-60% of adults with a severe and persistent mental illness experiencing a substance use disorder in their lifetime.

A study by Kessler et al. in the United States attempting to assess the prevalence of dual diagnosis found that 47% of clients with schizophrenia had a substance misuse disorder at some time in their life, and the chances of developing a substance misuse disorder was significantly higher among patients suffering from a psychotic illness than in those without a psychotic illness.

Another study looked at the extent of substance misuse in a group of 187 chronically mentally ill patients living in the community. According to the clinician's ratings, around a third of the sample used alcohol, street drugs, or both during the six months before evaluation.

Further UK studies have shown slightly more moderate rates of substance misuse among mentally ill individuals. One study found that individuals suffering from schizophrenia showed just a 7% prevalence of problematic drug use in the year prior to being interviewed and 21% reported problematic use some time before that.

Wright and colleagues identified individuals with psychotic illnesses who had been in contact with services in the London borough of Croydon over the previous 6 months. Cases of alcohol or substance misuse and dependence were identified through standardized interviews with clients and keyworkers. Results showed that prevalence rates of dual diagnosis were 33% for the use of any substance, 20% for alcohol misuse only and 5% for drug misuse only. A lifetime history of any illicit drug use was observed in 35% of the sample.

The condition gradually improves over a period of time which can range from six months to several years in more severe cases.

Flumazenil was found to be more effective than placebo in reducing feelings of hostility and aggression in patients who had been free of benzodiazepines for 4–266 weeks. This may suggest a role for flumazenil in treating protracted benzodiazepine withdrawal symptoms.

Acamprosate has been found to be effective in alleviating some of the post acute withdrawal symptoms of alcohol withdrawal. Carbamazepine or trazodone may also be effective in the treatment of post acute withdrawal syndrome in regards to alcohol use. Cognitive behavioral therapy can also help the post acute withdrawal syndrome especially when cravings are a prominent feature.