Substance abuse

thumb|A person using an inhalant

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 some persons are under the influence of a drug, and may result in long-term personality changes in individuals. 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.

thumb|right|Lines of cocaine prepared for snorting. [[Contaminated currency such as banknotes might serve as a fomite of diseases like hepatitis C]]

Drugs most often associated with this term include alcohol, amphetamines, barbiturates, benzodiazepines, cannabis, cocaine, hallucinogens, methaqualone, and opioids. The exact cause of substance abuse is sometimes unclear, but there are two predominant theories: either a genetic predisposition or a habit learned or passed down from others, which, if addiction develops, manifests itself as a possible chronic debilitating disease. It is not easy to determine why a person misuses drugs, as there are multiple environmental factors to consider. These factors include not only inherited biological influences (genes), but there are also mental health stressors such as overall quality of life, physical or mental abuse, luck and circumstance in life, and early exposure to drugs, all play a significant role in how people will respond to drug use.

In 2010, about 5% of adults (230 million) used an illicit substance. 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.

Classification

Public health definitions

thumb|A drug user receiving an injection of the [[opioid heroin]]

Public health practitioners have attempted to look at substance use from a broader perspective than the individual, emphasizing the role of society, culture, and availability. Some health professionals choose to avoid the terms alcohol or drug "abuse" in favor of language considered more objective, such as "substance and alcohol type problems" or "harmful/problematic use" of drugs. The Health Officers Council of British Columbia — in their 2005 policy discussion paper, A Public Health Approach to Drug Control in Canada — has adopted a public health model of psychoactive substance use that challenges the simplistic black-and-white construction of the binary (or complementary) antonyms "use" vs. "abuse". This model explicitly recognizes a spectrum of use, ranging from beneficial use to chronic dependence.

Medical definitions

[[File:Rational harm assessment of drugs radar plot.svg|thumb|upright=1.35|A 2007 assessment of harm from recreational drug use (mean physical harm and mean dependence liability)

Value judgment

thumb|upright=1.4|right|This diagram depicts the correlations among the usage of 18 legal and illegal drugs: alcohol, amphetamines, amyl nitrite, benzodiazepines, cannabis, chocolate, cocaine, caffeine, crack, ecstasy, heroin, ketamine, legal highs, LSD, methadone, magic mushrooms (MMushrooms), nicotine and volatile substance abuse (VSA). Usage is defined as having used the drug at least once during years 2005–2015. The colored links between drugs indicate the correlations with , where is the [[absolute value of the Pearson correlation coefficient.]]

History professor Philip Jenkins suggests that there are two issues with the term "drug abuse". First, what constitutes a drug is debatable. For instance, GHB, a naturally occurring substance in the central nervous system is considered a drug, and is illegal in many countries, while nicotine is not officially considered a "drug" in most countries.

Second, the word "abuse" implies a recognized standard of use for any substance. Drinking an occasional glass of wine is considered acceptable in most Western countries, while drinking several bottles is seen as abuse. Strict temperance advocates, who may or may not be religiously motivated, would see drinking even one glass as abuse. Similarly, adopting the view that any (recreational) use of cannabis or substituted amphetamines constitutes drug abuse implies a decision made that the substance is harmful, even in minute quantities. In the U.S., drugs have been legally classified into five categories; these are schedule I, II, III, IV, or V in the Controlled Substances Act. The drugs are classified on their deemed potential for abuse.

The usage of some drugs is strongly correlated. For example, the consumption of seven illicit drugs (amphetamines, cannabis, cocaine, ecstasy, legal highs, LSD, and magic mushrooms) is correlated and the Pearson correlation coefficient r>0.4 in every pair of them; consumption of cannabis is strongly correlated (r>0.5) with the usage of nicotine (tobacco), heroin is correlated with cocaine (r>0.4) and methadone (r>0.45), and is strongly correlated with crack (r>0.5) 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 misuse 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 nonmedical use of Vicodin; 1 in 20 reported such use of OxyContin." Both of these drugs contain opioids. Fentanyl is an opioid that is 100 times more potent than morphine, and 50 times more potent than heroin. 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.

Signs and symptoms

{| class="wikitable sortable" style="text-align:center; float:right; margin-left:8px; width:610px;"

|+ style="background:Khaki; border:1px solid black" | Rational scale to assess the harm of recreational drug use

! scope="col" | Drug

! scope="col" | Drug class

! scope="col" | Physical<br />harm

! scope="col" | Dependence<br />liability

! scope="col" | Social<br />harm

! scope="col" | Avg.<br />harm

<!-- Background colors used for levels of harm:

All colors are relatively pale to ensure high contrast with foreground black text, though are progressively slightly darker for each higher harm level as a possible aid to those with reduced color vision.

0.00–0.99: Yellow (#FFFFC0)

1.00–1.49: Orange (#FFE0C0)

1.50–1.99: Red (#FFC0C0)

2.00–3.00: Magenta (#FF90FF)

-->

| style="text-align:left" | Methamphetamine || style="text-align:left" | CNS stimulant || style="background: #FF90FF;" | 3.00 || style="background: #FF90FF;" | 2.80 || style="background: #FF90FF;" | 2.72 || style="background: #FF90FF;" | 2.92

| style="text-align:left" | Heroin || style="text-align:left" | Opioid || style="background: #FF90FF;" | 2.78 || style="background: #FF90FF;" | 3.00 || style="background: #FF90FF;" | 2.54 || style="background: #FF90FF;" | 2.77

| style="text-align:left" | Cocaine || style="text-align:left" | CNS stimulant || style="background: #FF90FF;" | 2.33 || style="background: #FF90FF;" | 2.39 || style="background: #FF90FF;" | 2.17 || style="background: #FF90FF;" | 2.30

| style="text-align:left" | Barbiturates || style="text-align:left" | CNS depressant || style="background: #FF90FF;" | 2.23 || style="background: #FF90FF;" | 2.01 || style="background: #FF90FF;" | 2.00 || style="background: #FF90FF;" | 2.08

| style="text-align:left" | Methadone || style="text-align:left" | Opioid || style="background: #FFC0C0;" | 1.86 || style="background: #FF90FF;" | 2.08 || style="background: #FFC0C0;" | 1.87 || style="background: #FFC0C0;" | 1.94

| style="text-align:left" | Alcohol || style="text-align:left" | CNS depressant || style="background: #FFE0C0;" | 1.40 || style="background: #FFC0C0;" | 1.93 || style="background: #FF90FF;" | 2.21 || style="background: #FFC0C0;" | 1.85

| style="text-align:left" | Ketamine || style="text-align:left" | Dissociative anesthetic || style="background: #FF90FF;" | 2.00 || style="background: #FFC0C0;" | 1.54 || style="background: #FFC0C0;" | 1.69 || style="background: #FFC0C0;" | 1.74

| style="text-align:left" | Benzodiazepines || style="text-align:left" | Benzodiazepine || style="background: #FFC0C0;" | 1.63 || style="background: #FFC0C0;" | 1.83 || style="background: #FFC0C0;" | 1.65 || style="background: #FFC0C0;" | 1.70

| style="text-align:left" | Amphetamine || style="text-align:left" | CNS stimulant || style="background: #FFC0C0;" | 1.81 || style="background: #FFC0C0;" | 1.67 || style="background: #FFC0C0;" | 1.50 || style="background: #FFC0C0;" | 1.66

| style="text-align:left" | Tobacco || style="text-align:left" | Tobacco ||style="background: #FFE0C0;" | 1.24 || style="background: #FF90FF;" | 2.21 || style="background: #FFE0C0;" | 1.42 || style="background: #FFC0C0;" | 1.62

| style="text-align:left" | Buprenorphine || style="text-align:left" | Opioid || style="background: #FFC0C0;" | 1.60 || style="background: #FFC0C0;" | 1.64 || style="background: #FFE0C0;" | 1.49 || style="background: #FFC0C0;" | 1.58

| style="text-align:left" | Cannabis || style="text-align:left" | Cannabinoid || style="background: #FFFFC0;" | 0.99 || style="background: #FFC0C0;" | 1.51 || style="background: #FFC0C0;" | 1.50 || style="background: #FFE0C0;" | 1.33

| style="text-align:left" | Solvent drugs || style="text-align:left" | Inhalant || style="background: #FFE0C0;" | 1.28 || style="background: #FFE0C0;" | 1.01 || style="background: #FFC0C0;" | 1.52 || style="background: #FFE0C0;" | 1.27

| style="text-align:left" | 4-MTA || style="text-align:left" | Designer SSRA || style="background: #FFE0C0;" | 1.44 || style="background: #FFE0C0;" | 1.30 || style="background: #FFE0C0;" | 1.06 || style="background: #FFE0C0;" | 1.27

| style="text-align:left" | LSD || style="text-align:left" | Psychedelic || style="background: #FFE0C0;" | 1.13 || style="background: #FFE0C0;" | 1.23 || style="background: #FFE0C0;" | 1.32 || style="background: #FFE0C0;" | 1.23

| style="text-align:left" | Methylphenidate || style="text-align:left" | CNS stimulant || style="background: #FFE0C0;" | 1.32 || style="background: #FFE0C0;" | 1.25 || style="background: #FFFFC0;" | 0.97 || style="background: #FFE0C0;" | 1.18

| style="text-align:left" | Anabolic steroids || style="text-align:left" | Anabolic steroid || style="background: #FFE0C0;" | 1.45 || style="background: #FFFFC0;" | 0.88 || style="background: #FFE0C0;" | 1.13 || style="background: #FFE0C0;" | 1.15

| style="text-align:left" | GHB || style="text-align:left" | Neurotransmitter || style="background: #FFFFC0;" | 0.86 || style="background: #FFE0C0;" | 1.19 || style="background: #FFE0C0;" | 1.30 || style="background: #FFE0C0;" | 1.12

| style="text-align:left" | Ecstasy || style="text-align:left" | Empathogenic stimulant || style="background: #FFE0C0;" | 1.05 || style="background: #FFE0C0;" | 1.13 || style="background: #FFE0C0;" | 1.09 || style="background: #FFE0C0;" | 1.09

| style="text-align:left" | Alkyl nitrites || style="text-align:left" | Inhalant || style="background: #FFFFC0;" | 0.93 || style="background: #FFFFC0;" | 0.87 || style="background: #FFFFC0;" | 0.97 || style="background: #FFFFC0;" | 0.92

| style="text-align:left" | Khat || style="text-align:left" | CNS stimulant || style="background: #FFFFC0;" | 0.50 || style="background: #FFE0C0;" | 1.04 || style="background: #FFFFC0;" | 0.85 || style="background: #FFFFC0;" | 0.80

! scope="col" colspan="6" |