Substance abuse disorder

A substance use disorder (SUD), also known as a drug use disorder, is a medical condition in which the use of one or more substances leads to a clinically significant impairment or distress. Substance use disorders are characterized by an array of mental, physical, and behavioral symptoms that may cause problems related to loss of control, strain to one's interpersonal life, hazardous use, tolerance, and withdrawal. Drug classes that are involved in SUD include alcohol, phencyclidine, inhalants, stimulants, cannabis, 'other hallucinogens', opioids, tobacco, and sedatives, hypnotics, and anxiolytics. Drug addiction and drug dependence are distinct components of substance use disorders. The severity of substance use disorders can vary widely; in the diagnosis of a SUD, the severity of an individual's SUD is qualified as mild, moderate, or severe on the basis of how many of the 11 diagnostic criteria are met. In the DSM-5, the term drug addiction is synonymous with severe substance use disorder. Worldwide 275 million people were estimated to have used an illicit drug in 2016. 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 or puts 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. The number of deaths directly caused by drug use has increased over 60 percent from 2000 to 2015. Substance abuse may lead to addiction, substance dependence, or both, depending upon the substance. Medically, physiologic dependence requires the development of tolerance leading to withdrawal symptoms. Both abuse and dependence are distinct from addiction which involves a compulsion to continue using the substance despite the negative consequences, and may or may not involve chemical dependency. Dependence often implies abuse, but abuse frequently occurs without dependence, particularly when an individual first begins to abuse a substance. Dependence involves physiological processes while substance abuse reflects a complex interaction between the individual, the abused substance and society. Substance abuse is sometimes used as a synonym for drug abuse, drug addiction, and chemical dependency, but actually refers to the use of substances in a manner outside sociocultural conventions. All use of controlled drugs and all use of other drugs in a manner not dictated by convention (e.g. according to physician's orders or societal norms) is abuse according to this definition; however there is no universally accepted definition of substance abuse. The physical harm for twenty drugs was compared in an article in the Lancet (see diagram, above right). Physical harm was assigned a value from 0 to 3 for acute harm, chronic harm and intravenous harm. Shown is the mean physical harm. Not shown, but also evaluated, was the social harm.