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ADDICTION is a brain disorder characterized by compulsive engagement in rewarding stimuli, despite adverse consequences. Despite the involvement of a number of psychosocial factors, a biological process – one which is induced by repeated exposure to an addictive stimulus – is the core pathology that drives the development and maintenance of an addiction. The two properties that characterize all addictive stimuli are that they are reinforcing (i.e., they increase the likelihood that a person will seek repeated exposure to them) and intrinsically rewarding (i.e., they are perceived as being inherently positive, desirable, and pleasurable).

Addiction
Addiction
is a disorder of the brain's reward system which arises through transcriptional and epigenetic mechanisms and occurs over time from chronically high levels of exposure to an addictive stimulus (e.g., morphine, cocaine, sexual intercourse, gambling, etc.). ΔFosB , a gene transcription factor , is a critical component and common factor in the development of virtually all forms of behavioral and drug addictions. Two decades of research into ΔFosB's role in addiction have demonstrated that addiction arises, and the associated compulsive behavior intensifies or attenuates, along with the overexpression of ΔFosB in the D1-type medium spiny neurons of the nucleus accumbens . Due to the causal relationship between ΔFosB expression and addictions, it is used preclinically as an addiction biomarker . ΔFosB expression in these neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement , while decreasing sensitivity to aversion.

As described by two groups of researchers, addiction exacts an "astoundingly high financial and human toll" on individuals and society as a whole through the direct adverse effects of drugs, associated healthcare costs, long-term complications (e.g., lung cancer with smoking tobacco, liver cirrhosis with drinking alcohol, or meth mouth from intravenous methamphetamine), the functional consequences of altered neural plasticity in the brain, and the consequent loss of productivity. Classic hallmarks of addiction include impaired control over substances or behavior, preoccupation with substance or behavior, and continued use despite consequences. Habits and patterns associated with addiction are typically characterized by immediate gratification (short-term reward), coupled with delayed deleterious effects (long-term costs).

Examples of drug and behavioral addictions include: alcoholism , amphetamine addiction , cocaine addiction , nicotine addiction , opiate addiction , food addiction , gambling addiction , and sexual addiction . The only behavioral addiction recognized by the DSM-5 is gambling addiction. The term addiction is misused frequently to refer to other compulsive behaviors or disorders, particularly dependence , in news media. An important distinction between drug addiction and dependence is that drug dependence is a disorder in which cessation of drug use results in an unpleasant state of withdrawal , which can lead to further drug use. Addiction
Addiction
is the compulsive use of a substance or performance of a behavior that is independent of withdrawal.

CONTENTS

* 1 Neuropsychology
Neuropsychology

* 1.1 Stimulus control of behavior * 1.2 Cognitive control
Cognitive control
of behavior

* 2 Behavioral addiction

* 3 Risk factors

* 3.1 Age * 3.2 Genetic factors * 3.3 Environmental factors * 3.4 Psychological factors * 3.5 Transgenerational epigenetic inheritance
Transgenerational epigenetic inheritance

* 4 Mechanisms

* 4.1 Summary of addiction-related plasticity

* 4.2 Reward system
Reward system

* 4.2.1 Mesocorticolimbic pathway * 4.2.2 Role of dopamine and glutamate

* 4.3 Reward sensitization

* 5 Diagnosis

* 6 Treatment

* 6.1 Behavioral therapy

* 6.2 Medication

* 6.2.1 Alcohol addiction * 6.2.2 Behavioral addictions * 6.2.3 Cannabinoid
Cannabinoid
addiction * 6.2.4 Nicotine addiction * 6.2.5 Opioid
Opioid
addiction * 6.2.6 Psychostimulant addiction * 6.2.7 Research

* 7 Epidemiology

* 7.1 Asia * 7.2 Australia * 7.3 Europe * 7.4 United States

* 8 Personality theories of addiction * 9 Notes * 10 See also * 11 References * 12 External links

NEUROPSYCHOLOGY

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Cognitive control
Cognitive control
and stimulus control , which is associated with operant and classical conditioning , represent opposite processes (i.e., internal vs external or environmental, respectively) that compete over the control of an individual's elicited behaviors. Cognitive control, and particularly inhibitory control over behavior , is impaired in both addiction and attention deficit hyperactivity disorder . Stimulus-driven behavioral responses (i.e., stimulus control) that are associated with a particular rewarding stimulus tend to dominate one's behavior in an addiction.

STIMULUS CONTROL OF BEHAVIOR

See also: Stimulus control </