Substance use disorder

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Substance use disorder
Classification and external resources
Specialty psychiatry
ICD-10 F10-F19
ICD-9-CM 303-305
MeSH D019966

Substance use disorder (SUD), also known as drug use disorder, is a condition in which the use of one or more substances leads to a clinically significant impairment or distress.[1] Although the term substance can refer to any physical matter, 'substance' in this context is limited to psychoactive drugs. Addiction and dependence are components of a substance use disorder and addiction represents the most severe form of the disorder.[2][3]

SUD refers to the overuse of, or dependence on, a drug leading to effects that are detrimental to the individual's physical and mental health, or the welfare of others.[4] SUD is characterized by a pattern of continued pathological use of a medication, non-medically indicated drug or toxin, which results in repeated adverse social consequences related to drug use, such as failure to meet work, family, or school obligations, interpersonal conflicts, or legal problems.

There are on-going debates as to the exact distinctions between substance abuse and substance dependence, but current practice standard distinguishes between the two by defining substance dependence in terms of physiological and behavioral symptoms of substance use, and substance abuse in terms of the social consequences of substance use.[5] In the DSM-5 substance use disorder replaced substance abuse and substance dependence.[6][7][8]

In 2010 about 5% of people (230 million) used an illicit substance.[9] 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.[9][10] In 2015 substance use disorders resulted in 307,400 deaths, up from 165,000 deaths in 1990.[11][12] 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.[11]

Definitions[edit]

Addiction and dependence glossary[13][14][15][16]
addiction – a brain disorder characterized by compulsive engagement in rewarding stimuli despite adverse consequences
addictive behavior – a behavior that is both rewarding and reinforcing
addictive drug – a drug that is both rewarding and reinforcing
dependence – an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake)
drug sensitization or reverse tolerance – the escalating effect of a drug resulting from repeated administration at a given dose
drug withdrawal – symptoms that occur upon cessation of repeated drug use
physical dependence – dependence that involves persistent physical–somatic withdrawal symptoms (e.g., fatigue and delirium tremens)
psychological dependence – dependence that involves emotional–motivational withdrawal symptoms (e.g., dysphoria and anhedonia)
reinforcing stimuli – stimuli that increase the probability of repeating behaviors paired with them
rewarding stimuli – stimuli that the brain interprets as intrinsically positive and desirable or as something to be approached
sensitization – an amplified response to a stimulus resulting from repeated exposure to it
substance use disorder - a condition in which the use of substances leads to clinically and functionally significant impairment or distress
tolerance – the diminishing effect of a drug resulting from repeated administration at a given dose
(edit | history)

Substance abuse may lead to addiction, substance dependence, or both. 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.[17]

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)[citation needed]. 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.

Substance use may be better understood as occurring on a spectrum from beneficial to problematic use. This conceptualization moves away from the ill-defined binary antonyms of "use" vs. "abuse" (see diagram, lower right) towards a more nuanced, public health-based understanding of substance use.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV TR) describes physical dependence, abuse of, and withdrawal from drugs and other substances. It does not use the word 'addiction' at all. It has instead a section about substance dependence:

"Substance dependence When an individual persists in use of alcohol or other drugs despite problems related to use of the substance, substance dependence may be diagnosed. Compulsive and repetitive use may result in tolerance to the effect of the drug and withdrawal symptoms when use is reduced or stopped. This, along with Substance Abuse are considered Substance Use Disorders..."[18]

Signs and symptoms[edit]

The DSM definition of addiction can be boiled down to compulsive use of a substance (or engagement in an activity) despite ongoing negative consequences. The medical community makes a distinction between physical dependence (characterized by symptoms of physical withdrawal symptoms, like tremors and sweating) and psychological dependence (emotional-motivational withdrawal symptoms). Physical dependence is simply needing a substance to function. Humans are all physically dependent upon oxygen, food and water. A drug can cause physical dependence and not psychological dependence (for example, some blood pressure medications, which can produce fatal withdrawal symptoms if not tapered) and some can cause psychological dependence without physical dependence (the withdrawal symptoms associated with cocaine are all psychological, there is no associated vomiting or diarrhea as there is with opiate withdrawal).

There are several different screening tools that have been validated for use with adolescents such as the CRAFFT and adults such as the CAGE.

Addiction[edit]

Physical dependency[edit]

Physical dependence on a substance is defined by the appearance of characteristic physical withdrawal symptoms when the substance is suddenly discontinued. Opiates, benzodiazepines, barbiturates, alcohol and nicotine induce physical dependence. On the other hand, some categories of substances share this property and are still not considered addictive: cortisone, beta blockers and most antidepressants are examples.

Some substances induce physical dependence or physiological tolerance - but not addiction — for example many laxatives, which are not psychoactive; nasal decongestants, which can cause rebound congestion if used for more than a few days in a row; and some antidepressants, most notably venlafaxine, paroxetine and sertraline, as they have quite short half-lives, so stopping them abruptly causes a more rapid change in the neurotransmitter balance in the brain than many other antidepressants. Many non-addictive prescription drugs should not be suddenly stopped, so a doctor should be consulted before abruptly discontinuing them.

The speed with which a given individual becomes addicted to various substances varies with the substance, the frequency of use, the means of ingestion, the intensity of pleasure or euphoria, and the individual's genetic and psychological susceptibility. Some people may exhibit alcoholic tendencies from the moment of first intoxication, while most people can drink socially without ever becoming addicted. Opioid dependent individuals have different responses to even low doses of opioids than the majority of people, although this may be due to a variety of other factors, as opioid use heavily stimulates pleasure-inducing neurotransmitters in the brain. Nonetheless, because of these variations, in addition to the adoption and twin studies that have been well replicated, much of the medical community is satisfied that addiction is in part genetically moderated. That is, one's genetic makeup may regulate how susceptible one is to a substance and how easily one may become attached to a pleasurable routine.

Eating disorders are complicated pathological mental illnesses and thus are not the same as addictions described in this article. Eating disorders, which some argue are not addictions at all, are driven by a multitude of factors, most of which are highly different from the factors behind addictions described in this article. It has been reported, however, that patients with eating disorders can successfully be treated with the same non-pharmacological protocols used in patients with chemical addiction disorders.[19]

Gambling is another potentially addictive behavior with some biological overlap. Conversely gambling urges have emerged with the administration of Mirapex (pramipexole), a dopamine agonist.[20]

The obsolete term physical addiction is deprecated, because of its connotations. In modern pain management with opioids physical dependence is nearly universal. High-quality, long-term studies are needed to better delineate the risks and benefits of chronic opiate use.[citation needed]

Psychological dependency[edit]

Psychological dependency on a substance is defined by the appearance of emotional-motivational withdrawal symptoms (e.g., anxiety, irritability, anhedonia, depressed mood, restlessness, etc.) when the substance is suddenly discontinued. Psychological dependence is not unique to substances; for example, separation anxiety occurs in young children when they lack exposure to individuals to whom they're emotionally attached.

Causes[edit]

Risk factors[edit]

As demonstrated by the chart below, numerous studies have examined factors which mediate substance abuse or dependence. In these examples, the predictor variables lead to the mediator which in turn leads to the outcome, which is always substance abuse or dependence. For example, research has found that being raised in a single-parent home can lead to increased exposure to stress and that increased exposure to stress, not being raised in a single-parent home, leads to substance abuse or dependence.[21] The following are some, but by no means all, of the possible mediators of substance abuse.

Predictor Variables Mediator Variables Outcome Variable
Single-parent Home[21] Exposure to Stress, Association w/ Deviant Peers Substance Abuse or Dependence
Child Abuse/Neglect[22] PTSD symptoms, Stressful Life Events, Criminal Behavior Substance Abuse or Dependence
Parental Substance Abuse[23]

Witnessing Violence

Physical/Sexual Abuse

Delinquency Status

Substance Abuse or Dependence

As demonstrated by the chart below, numerous studies have examined factors which moderate substance abuse or dependence. In these examples, the moderator variable impacts the level to which the strength of the relationship varies between a given predictor variable and the outcome of substance abuse or dependence. For example, there is a significant relationship between psychobehavioral risk factors, such as tolerance of deviance, rebelliousness, achievement, perceived drug risk, familism, family church attendance and other factors, and substance abuse and dependence. That relationship is moderated by familism which means that the strength of the relationship is increased or decreased based on the level of familism present in a given individual.[24]

Predictor Variables Moderator Variables Outcome Variable
Psychobehavioral Risk[24] Familism

Family Church Attendance

Substance Abuse or Dependence
Victimization Effects[23] Race/Ethnicity

Physical/Sexual Abuse

Substance Abuse or Dependence
Family History of Alcoholism[25] Gender Substance Abuse or Dependence

Examples of mediators and moderators can be found in several empirical studies. For example, Pilgrim et al.’s hypothesized mediation model posited that school success and time spent with friends mediated the relationship between parental involvement and risk-taking behavior with substance use (2006).[26] More specifically, the relationship between parental involvement and risk-taking behavior is explained via the interaction with third variables, school success and time spent with friends. In this example, increased parental involvement led to increased school success and decreased time with friends, both of which were associated with decreased drug use. Another example of mediation involved risk-taking behaviors. As risk-taking behaviors increased, school success decreased and time with friends increased, both of which were associated with increased drug use. A second example of a mediating variable is depression. In a study by Lo and Cheng (2007),[27] depression was found to mediate the relationship between childhood maltreatment and subsequent substance abuse in adulthood. In other words, childhood physical abuse is associated with increased depression, which in turn, in associated with increased drug and alcohol use in young adulthood. More specifically, depression helps to explain how childhood abuse is related to subsequent substance abuse in young adulthood.

A third example of a mediating variable is an increase of externalizing symptoms. King and Chassin (2008)[28] conducted research examining the relationship between stressful life events and drug dependence in young adulthood. Their findings identified problematic externalizing behavior on subsequent substance dependency. In other words, stressful life events are associated with externalizing symptoms, such as aggression or hostility, which can lead to peer alienation or acceptance by socially deviant peers, which could lead to increased drug use. The relationship between stressful life events and subsequent drug dependence however exists via the presence of the mediation effects of externalizing behaviors.

An example of a moderating variable is level of cognitive distortion. An individual with high levels of cognitive distortion might react adversely to potentially innocuous events, and may have increased difficulty reacting to them in an adaptive manner (Shoal & Giancola, 2005).[29] In their study, Shoal and Giancola investigated the moderating effects of cognitive distortion on adolescent substance use. Individuals with low levels of cognitive distortion may be more apt to choose more adaptive methods of coping with social problems, thereby potentially reducing the risk of drug use. Individuals with high levels of cognitive distortions, because of their increased misperceptions and misattributions, are at increased risk for social difficulties. Individuals may be more likely to react aggressively or inappropriately, potentially alienating themselves from their peers, thereby putting them at greater risk for delinquent behaviors, including substance use and abuse. In this study, social problems are a significant risk factor for drug use when moderated by high levels of cognitive distortions.

Mechanisms[edit]

Addiction[edit]

ΔFosB, a gene transcription factor, has been identified as playing a critical role in the development of an addiction.[30][31][32] Overexpression of ΔFosB in the nucleus accumbens is necessary and sufficient for many of the neural adaptations seen in drug addiction;[30] it has been implicated in addictions to alcohol, cannabinoids, cocaine, nicotine, phenylcyclidine, and substituted amphetamines[30][33][34][35] as well as addictions to natural rewards such as sex, exercise, and food.[31][32] Moreover, reward cross-sensitization between amphetamine and sexual activity, a property in which exposure to one increases in the desire for both, has been shown to occur preclinically and clinically as a dopamine dysregulation syndrome;[32][36] ΔFosB expression is required for this cross-sensitization effect, which intensifies with the level of ΔFosB expression.[32]

Dependence[edit]

Upregulation of the cyclic adenosine monophosphate (cAMP) signal transduction pathway by cAMP response element binding protein (CREB), a gene transcription factor, in the nucleus accumbens is a common mechanism of psychological dependence among several classes of drugs of abuse.[37][13] Upregulation of the same pathway in the locus coeruleus is also a mechanism responsible for certain aspects of opioid-induced physical dependence.[37][13]

Increased brain-derived neurotrophic factor (BDNF) signaling in the ventral tegmental area (VTA) has been shown to mediate opiate-induced withdrawal symptoms via downregulation of insulin receptor substrate 2 (IRS2), protein kinase B (AKT), and mechanistic target of rapamycin complex 2 (mTORC2).[13][38] As a result of downregulated signaling through these proteins, opiates cause VTA neuronal hyperexcitability and shrinkage (specifically, the size of the neuronal soma is reduced).[13] It has been shown that when an opiate-naive person begins using opiates in concentrations that induce euphoria, BDNF signaling increases in the VTA.[39]

Management[edit]

Addiction severity index[edit]

Some medical systems, including those of at least 15 states of the United States, refer to an Addiction Severity Index[40] to assess the severity of problems related to substance use. According to DARA Thailand,[41] the index assesses potential problems in seven categories: medical, employment/support, alcohol, other drug use, legal, family/social, and psychiatric.

Detoxification[edit]

Early treatment of acute withdrawal often includes medical detoxification, which can include doses of anxiolytics or narcotics to reduce symptoms of withdrawal. An experimental drug, ibogaine,[42] is also proposed to treat withdrawal and craving.

Neurofeedback therapy has shown statistically significant improvements in numerous researches [2] conducted on alcoholic as well as mixed substance abuse population. In chronic opiate addiction, a surrogate drug such as methadone is sometimes offered as a form of opiate replacement therapy. But treatment approaches universal focus on the individual's ultimate choice to pursue an alternate course of action.

Tailoring treatment[edit]

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.

Treatments
Behavioral pattern Intervention Goals
Low self-esteem, anxiety, verbal hostility Relationship therapy, client centered approach Increase self-esteem, reduce hostility and anxiety
Defective personal constructs, ignorance of interpersonal means Cognitive restructuring including directive and group therapies Insight
Focal anxiety such as fear of crowds Desensitization Change response to same cue
Undesirable behaviors, lacking appropriate behaviors Aversive conditioning, operant conditioning, counter conditioning Eliminate or replace behavior
Lack of information Provide information Have client act on information
Difficult social circumstances Organizational intervention, environmental manipulation, family counseling Remove cause of social difficulty
Poor social performance, rigid interpersonal behavior Sensitivity training, communication training, group therapy Increase interpersonal repertoire, desensitization to group functioning
Grossly bizarre behavior Medical referral Protect from society, prepare for further treatment
Adapted from: Essentials of Clinical Dependency Counseling, Aspen Publishers

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.[43][44] In addition, the same author suggests that social skills training adjunctive to inpatient treatment of alcohol dependence is probably efficacious.

Epidemiology[edit]

The disability-adjusted life year, a measure of overall disease burden (number of years lost due to ill-health, disability or early death), from drug use disorders per 100,000 inhabitants in 2004
  no data
  <40
  40-80
  80-120
  120-160
  160-200
  200-240
  240-280
  280-320
  320-360
  360-400
  400-440
  >440

In 2013 drug use disorders resulted in 127,000 deaths up from 53,000 in 1990.[12] The highest number of deaths are from opioid use disorders at 51,000.[12] Alcohol use disorders resulted in an addition 139,000 deaths.[12]

About 10.6% of Americans with substance use disorder seek treatment, and 40-60% of those people relapse within a year.[45]

Legality[edit]

Most countries have legislation which brings various drugs and drug-like substances under the control of licensing systems. Typically this legislation covers any or all of the opiates, substituted amphetamines, cannabinoids, cocaine, barbiturates, hallucinogens (tryptamines, LSD, phencyclidine, and psilocybin) and a variety of more modern synthetic drugs, and unlicensed production, supply or possession may be a criminal offense.

Usually, however, drug classification under such legislation is not related simply to addictiveness. The substances covered often have very different addictive properties. Some are highly prone to cause physical dependency, whilst others rarely cause any form of compulsive need whatsoever.

Also, although the legislation may be justifiable on moral grounds to some, it can make addiction or dependency a much more serious issue for the individual. Reliable supplies of a drug become difficult to secure as illegally produced substances may have contaminants. Withdrawal from the substances or associated contaminants can cause additional health issues and the individual becomes vulnerable to both criminal abuse and legal punishment. Criminal elements that can be involved in the profitable trade of such substances can also cause physical harm to users.

Opposition to common views[edit]

Thomas Szasz denies that addiction is a psychiatric problem. In many of his works, he argues that addiction is a choice, and that a drug addict is one who simply prefers a socially taboo substance rather than, say, a low risk lifestyle. In Our Right to Drugs, Szasz cites the biography of Malcolm X to corroborate his economic views towards addiction: Malcolm claimed that quitting cigarettes was harder than shaking his heroin addiction. Szasz postulates that humans always have a choice, and it is foolish to call someone an "addict" just because they prefer a drug induced euphoria to a more popular and socially welcome lifestyle.

Professor John Booth Davies at the University of Strathclyde has argued in his book The Myth of Addiction that "people take drugs because they want to and because it makes sense for them to do so given the choices available" as opposed to the view that "they are compelled to by the pharmacology of the drugs they take."[46] He uses an adaptation of attribution theory (what he calls the theory of functional attributions) to argue that the statement "I am addicted to drugs" is functional, rather than veridical. Stanton Peele has put forward similar views.

See also[edit]

References[edit]

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    Addiction: A term used to indicate the most severe, chronic stage of substance-use disorder, in which there is a substantial loss of self-control, as indicated by compulsive drug taking despite the desire to stop taking the drug. In the DSM-5, the term addiction is synonymous with the classification of severe substance-use disorder.
     
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