Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder. Differing definitions of drug misuse are used in public health, medical, and criminal justice contexts. In some cases, criminal or anti-social behavior occurs when the person is under the influence of a drug, and long-term personality changes in individuals may also occur. In addition to possible physical, social, and psychological harm, the use of some drugs may also lead to criminal penalties, although these vary widely depending on the local jurisdiction.
Alcohol abuse encompasses a spectrum of alcohol-related substance abuse, ranging from the consumption of more than 2 drinks per day on average for men, or more than 1 drink per day on average for women, to binge drinking or alcohol use disorder.
Drug withdrawal, drug withdrawal syndrome, or substance withdrawal syndrome is the group of symptoms that occur upon the abrupt discontinuation or decrease in the intake of pharmaceutical or recreational drugs.
Alcohol dependence is a previous psychiatric diagnosis in which an individual is physically or psychologically dependent upon alcohol.
Physical dependence is a physical condition caused by chronic use of a tolerance-forming drug, in which abrupt or gradual drug withdrawal causes unpleasant physical symptoms. Physical dependence can develop from low-dose therapeutic use of certain medications such as benzodiazepines, opioids, stimulants, antiepileptics and antidepressants, as well as the recreational misuse of drugs such as alcohol, opioids and benzodiazepines. The higher the dose used, the greater the duration of use, and the earlier age use began are predictive of worsened physical dependence and thus more severe withdrawal syndromes. Acute withdrawal syndromes can last days, weeks or months. Protracted withdrawal syndrome, also known as post-acute-withdrawal syndrome or "PAWS", is a low-grade continuation of some of the symptoms of acute withdrawal, typically in a remitting-relapsing pattern, often resulting in relapse and prolonged disability of a degree to preclude the possibility of lawful employment. Protracted withdrawal syndrome can last for months, years, or depending on individual factors, indefinitely. Protracted withdrawal syndrome is noted to be most often caused by benzodiazepines. To dispel the popular misassociation with addiction, physical dependence to medications is sometimes compared to dependence on insulin by persons with diabetes.
Substance dependence, also known as drug dependence, is a biopsychological situation whereby an individual's functionality is dependent on the necessitated re-consumption of a psychoactive substance because of an adaptive state that has developed within the individual from psychoactive substance consumption that results in the experience of withdrawal and that necessitates the re-consumption of the drug. A drug addiction, a distinct concept from substance dependence, is defined as compulsive, out-of-control drug use, despite negative consequences. An addictive drug is a drug which is both rewarding and reinforcing. ΔFosB, a gene transcription factor, is now known to be a critical component and common factor in the development of virtually all forms of behavioral and drug addictions, but not dependence.
Sexual addiction is a state characterized by compulsive participation or engagement in sexual activity, particularly sexual intercourse, despite negative consequences. The concept is contentious; as of 2023, sexual addiction is not a clinical diagnosis in either the DSM or ICD medical classifications of diseases and medical disorders, which instead categorize such behaviors under labels such as compulsive sexual behavior.
An addictive behavior is a behavior, or a stimulus related to a behavior, that is both rewarding and reinforcing, and is associated with the development of an addiction. There are two main forms of addiction: substance use disorders and behavioral addiction. The parallels and distinctions between behavioral addictions and other compulsive behavior disorders like bulimia nervosa and obsessive-compulsive disorder (OCD) are still being researched by behavioral scientists.
Dual diagnosis is the condition of having a mental illness and a comorbid substance use disorder. There is considerable debate surrounding the appropriateness of using a single category for a heterogeneous group of individuals with complex needs and a varied range of problems. The concept can be used broadly, for example depression and alcohol use disorder, or it can be restricted to specify severe mental illness and substance use disorder, or a person who has a milder mental illness and a drug dependency, such as panic disorder or generalized anxiety disorder and is dependent on opioids. Diagnosing a primary psychiatric illness in people who use substances is challenging as substance use disorder itself often induces psychiatric symptoms, thus making it necessary to differentiate between substance induced and pre-existing mental illness.
Cocaine dependence is a neurological disorder that is characterized by withdrawal symptoms upon cessation from cocaine use. It also often coincides with cocaine addiction which is a biopsychosocial disorder characterized by persistent use of cocaine and/or crack despite substantial harm and adverse consequences. The Diagnostic and Statistical Manual of Mental Disorders, classifies problematic cocaine use as a stimulant use disorder. The International Classification of Diseases, includes "Cocaine dependence" as a classification (diagnosis) under "Disorders due to use of cocaine".
Post-acute withdrawal syndrome (PAWS) is a hypothesized set of persistent impairments that occur after withdrawal from alcohol, opiates, benzodiazepines, antidepressants, and other substances. Infants born to mothers who used substances of dependence during pregnancy may also experience a PAWS. While PAWS has been frequently reported by those withdrawing from opiate and alcohol dependence, the research has limitations. Protracted benzodiazepine withdrawal has been observed to occur in some individuals prescribed benzodiazepines.
Psychological dependence is a cognitive disorder and a form of dependence that is characterized by emotional–motivational withdrawal symptoms upon cessation of prolonged drug use or certain repetitive behaviors. Consistent and frequent exposure to particular substances or behaviors is responsible for inducing psychological dependence, requiring ongoing engagement to prevent the onset of an unpleasant withdrawal syndrome driven by negative reinforcement. Neuronal counter-adaptation is believed to contribute to the generation of withdrawal symptoms through changes in neurotransmitter activity or altered receptor expression. Environmental enrichment and physical activity have been shown to attenuate withdrawal symptoms.
Behavioral addiction, process addiction, or non-substance-related disorder is a form of addiction that involves a compulsion to engage in a rewarding non-substance-related behavior – sometimes called a natural reward – despite any negative consequences to the person's physical, mental, social or financial well-being. In the brain's reward system, a gene transcription factor known as ΔFosB has been identified as a necessary common factor involved in both behavioral and drug addictions, which are associated with the same set of neural adaptations.
Polysubstance dependence refers to a type of substance use disorder in which an individual uses at least three different classes of substances indiscriminately and does not have a favorite substance that qualifies for dependence on its own. Although any combination of three substances can be used, studies have shown that alcohol is commonly used with another substance. One study on polysubstance use categorized participants who used multiple substances according to their substance of preference. The results of a longitudinal study on substance use led the researchers to observe that excessively using or relying on one substance increased the probability of excessively using or relying on another substance.
Benzodiazepine dependence defines a situation in which one has developed one or more of either tolerance, withdrawal symptoms, drug seeking behaviors, such as continued use despite harmful effects, and maladaptive pattern of substance use, according to the DSM-IV. In the case of benzodiazepine dependence, the continued use seems to be typically associated with the avoidance of unpleasant withdrawal reaction rather than with the pleasurable effects of the drug. Benzodiazepine dependence develops with long-term use, even at low therapeutic doses, often without the described drug seeking behavior and tolerance.
Substance use disorder (SUD) is the persistent use of drugs despite substantial harm and adverse consequences to self and others. Related terms include substance use problems and problematic drug or alcohol use.
Addiction is a neuropsychological disorder characterized by a persistent and intense urge to use a drug or engage in a behavior that produces natural reward, despite substantial harm and other negative consequences. Repetitive drug use can alter brain function in synapses similar to natural rewards like food or falling in love in ways that perpetuate craving and weakens self-control for people with pre-existing vulnerabilities. This phenomenon – drugs reshaping brain function – has led to an understanding of addiction as a brain disorder with a complex variety of psychosocial as well as neurobiological factors that are implicated in the development of addiction. While mice given cocaine showed the compulsive and involuntary nature of addiction, for humans this is more complex, related to behavior or personality traits.
Cannabis use disorder (CUD), also known as cannabis addiction or marijuana addiction, is a psychiatric disorder defined in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and ICD-10 as the continued use of cannabis despite clinically significant impairment.
Stimulant use disorder is a type of substance use disorder where the use of stimulants caused clinically significant impairment or distress. It is defined in the DSM-5 as "the continued use of amphetamine-type substances, cocaine, or other stimulants leading to clinically significant impairment or distress, from mild to severe". These psychoactive drugs, known as stimulants, are among the most widely used drugs in the world today, although not all stimulants can induce addiction.
