Substance abuse, also known as drug abuse, is a patterned use of a drug in which the user consumes the substance in amounts or with methods which are harmful to themselves or others, and is a form of substance-related disorder. Widely differing definitions of drug abuse are used in public health, medical and criminal justice contexts. In some cases criminal or anti-social behaviour occurs when the person is under the influence of a drug, and long term personality changes in individuals may occur as well. In addition to possible physical, social, and psychological harm, use of some drugs may also lead to criminal penalties, although these vary widely depending on the local jurisdiction.

Drugs most often associated with this term include:
 alcohol, cannabis, barbiturates, benzodiazepines, cocaine, methaqualone, opioids and some substituted amphetamines like methamphetamine and MDMA.

The exact cause of substance abuse is not clear, with the two predominant theories being: either a genetic disposition which is learned from others, or a habit which if addiction develops, manifests itself as a chronic debilitating disease.

In 2010 about 5% of people (230 million) used an illicit substance. Of these 27 million have high-risk drug use otherwise known as recurrent drug use causing harm to their health, psychological problems, or social problems that put them at risk of those dangers. In 2015 substance use disorders resulted in 307,400 deaths, up from 165,000 deaths in 1990. Of these, the highest numbers are from alcohol use disorders at 137,500, opioid use disorders at 122,100 deaths, amphetamine use disorders at 12,200 deaths, and cocaine use disorders at 11,100.

Drug misuse

Drug misuse is a term used commonly when prescription medication with sedative, anxiolytic, analgesic, or stimulant properties are used for mood alteration or intoxication ignoring the fact that overdose of such medicines can sometimes have serious adverse effects. It sometimes involves drug diversion from the individual for whom it was prescribed.

Prescription misuse has been defined differently and rather inconsistently based on status of drug prescription, the uses without a prescription, intentional use to achieve intoxicating effects, route of administration, co-ingestion with alcohol, and the presence or absence of dependence symptoms. Chronic use of certain substances leads to a change in the central nervous system known as a ‘tolerance’ to the medicine such that more of the substance is needed in order to produce desired effects. With some substances, stopping or reducing use can cause withdrawal symptoms to occur,[ but this is highly dependent on the specific substance in question.

The rate of prescription drug use is fast overtaking illegal drug use in the United States. According to the National Institute of Drug Abuse, 7 million people were taking prescription drugs for nonmedical use in 2010. Among 12th graders, nonmedical prescription drug use is now second only to cannabis. In 2011, “Nearly 1 in 12 high school seniors reported non-medical use of Vicodin; 1 in 20 reported such use of Oxycontin.” Both of these drugs contain opioids. A 2017 survey of 12th graders in the United States, found misuse of Oxycontin of 2.7 percent, compared to 5.5 percent at its peak in 2005. Misuse of the combination hydrocodone/paracetamol was at its lowest since a peak of 10.5 percent in 2003. This decrease may be related to public health initiatives and decreased availability.

Avenues of obtaining prescription drugs for misuse are varied: sharing between family and friends, illegally buying medications at school or work, and often “doctor shopping” to find multiple physicians to prescribe the same medication, without knowledge of other prescribes.

Increasingly, law enforcement is holding physicians responsible for prescribing controlled substances without fully establishing patient controls, such as a patient “drug contract”. Concerned physicians are educating themselves on how to identify medication-seeking behavior in their patients, and are becoming familiar with “red flags” that would alert them to potential prescription drug abuse.

Signs and symptoms

DrugDrug classPhysical
CocaineCNS stimulant2.332.392.172.30
BarbituratesCNS depressant2.
AlcoholCNS depressant1.401.932.211.85
KetamineDissociative anesthetic2.001.541.691.74
AmphetamineCNS stimulant1.811.671.501.66
Solvent drugsInhalant1.281.011.521.27
4-MTADesigner SSRA1.441.301.061.27
MethylphenidateCNS stimulant1.321.250.971.18
Anabolic steroidsAnabolic steroid1.450.881.131.15
EcstasyEmpathogenic stimulant1.
Alkyl nitritesInhalant0.930.870.970.92
KhatCNS stimulant0.501.040.850.80

Depending on the actual compound, drug abuse including alcohol may lead to health problems, social problems, morbidity, injuries, unprotected sex, violence, deaths, motor vehicle accidents, homicides, suicides, physical dependence or psychological addiction.[

There is a high rate of suicide in alcoholics and other drug abusers. The reasons believed to cause the increased risk of suicide include the long-term abuse of alcohol and other drugs causing physiological distortion of brain chemistry as well as the social isolation. Another factor is the acute intoxicating effects of the drugs may make suicide more likely to occur. Suicide is also very common in adolescent alcohol abusers, with 1 in 4 suicides in adolescents being related to alcohol abuse In the US, approximately 30% of suicides are related to alcohol abuse. Alcohol abuse is also associated with increased risks of committing criminal offences including child abuse, domestic violence, rapes, burglaries and assaults.[

Drug abuse, including alcohol and prescription drugs, can induce symptomatology which resembles mental illness. This can occur both in the intoxicated state and also during the withdrawal state. In some cases these substance induced psychiatric disorders can persist long after detoxification, such as prolonged psychosis or depression after amphetamine or cocaine abuse. A protracted withdrawal syndrome can also occur with symptoms persisting for months after cessation of use. Benzodiazepines are the most notable drug for inducing prolonged withdrawal effects with symptoms sometimes persisting for years after cessation of use. Both alcohol, barbiturate as well as benzodiazepine withdrawal can potentially be fatal. Abuse of hallucinogens can trigger delusional and other psychotic phenomena long after cessation of use.

Cannabis may trigger panic attacks during intoxication and with continued use, it may cause a state similar to dysthymia. Researchers have found that daily cannabis use and the use of high-potency cannabis are independently associated with a higher chance of developing schizophrenia and other psychotic disorders.[

Severe anxiety and depression are commonly induced by sustained alcohol abuse, which in most cases abates with prolonged abstinence. Even sustained moderate alcohol use may increase anxiety and depression levels in some individuals. In most cases these drug induced psychiatric disorders fade away with prolonged abstinence.[


Impulsivity is characterized by actions based on sudden desires, whims, or inclinations rather than careful thought.[ Individuals with substance abuse have higher levels of impulsivity, and individuals who use multiple drugs tend to be more impulsive.[ A number of studies using the Iowa gambling task as a measure for impulsive behavior found that drug using populations made more risky choices compared to healthy controls.[ There is a hypothesis that the loss of impulse control may be due to impaired inhibitory control resulting from drug induced changes that take place in the frontal cortex.[ The neuro developmental and hormonal changes that happen during adolescence may modulate impulse control that could possibly lead to the experimentation with drugs and may lead to the road of addiction. Impulsivity is thought to be a facet trait in the neuroticism personality domain (overindulgence/negative urgency) which is prospectively associated with the development of substance abuse

Screening and assessment

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.[



From the applied behavior analysis literature, behavioral psychology, and from randomized clinical trials, several evidenced based interventions have emerged: behavioral marital therapy, motivational Interviewing, community reinforcement approach, exposure therapy, contingency management. They help suppress cravings and mental anxiety, improve focus on treatment and new learning behavioral skills, ease withdrawal symptoms and reduce the chances of relapse.

In children and adolescents, cognitive behavioral therapy (CBT)[ and family therapy currently has the most research evidence for the treatment of substance abuse problems. Well-established studies also include ecological family-based treatment and group CBT. These treatments can be administered in a variety of different formats, each of which has varying levels of research support Research has shown that what makes group CBT most effective is that it promotes the development of social skills, developmentally appropriate emotional regulatory skills and other interpersonal skills.[ A few integrated[ treatment models, which combines parts from various types of treatment, have also been seen as both well-established or probably effective.[ A study on maternal alcohol and drug use has shown that integrated treatment programs have produced significant results, resulting in higher negative results on toxicology screens.[ Additionally, brief school-based interventions have been found to be effective in reducing adolescent alcohol and cannabis use and abuse.[ Motivational interviewing can also be effective in treating substance use disorder in adolescents.[

Alcoholics Anonymous and Narcotics Anonymous are one of the most widely known self-help organizations in which members support each other not to use alcohol.[ Social skills are significantly impaired in people suffering from alcoholism due to the neurotoxic effects of alcohol on the brain, especially the prefrontal cortex area of the brain.[ It has been suggested that social skills training adjunctive to inpatient treatment of alcohol dependence is probably efficacious,[ including managing the social environment.


A number of medications have been approved for the treatment of substance abuse.[ These include replacement therapies such as buprenorphine and methadone as well as antagonist medications like disulfiram and naltrexone in either short acting, or the newer long acting form. Several other medications, often ones originally used in other contexts, have also been shown to be effective including bupropion and modafinil. Methadone and buprenorphine are sometimes used to treat opiate addiction.[ These drugs are used as substitutes for other opioids and still cause withdrawal symptoms.

Antipsychotic medications have not been found to be useful. Acamprostate[ is a glutamatergic NMDA antagonist, which helps with alcohol withdrawal symptoms because alcohol withdrawal is associated with a hyperglutamatergic system.

Dual diagnosis

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.[