DRUG ADDICTION

"Absinthe Drinker"Pablo Picasso (1910)

What is Addiction?

Defined by tolerance, withdrawal, & compulsion

Involves a person's heightened and habituated need for a substance (or engagement in a particular behavior)

It causes discomfort or suffering that results from discontinuation of its use

Addicted individuals will sacrifice things and people they value (to the point of self-destruction) for their addiction.

Drug addiction is conceptualized as a chronic relapsing syndrome that moves from an impulse control disorder involving positive reinforcement to a compulsive disorder involving negative reinforcement

Drug Addiction

From: Koob GF, Alcohol Clin Exp Res, 2003, 27:232-243.

Drug Addiction in Context

Prevalence of Addiction Addiction Across Cultures Heredity Influences in Addiction Environmental

Drug use is a learned coping strategy in response to past learning and current life events

Diathesis/Stress ModelGenetic predisposition combined with

environmental factors

Causes of Addiction:Personality-Heredity

Particular personality traits predispose one to addiction

Sensation seekingThe seeking of novel experiences and sensations

ImpulsivityAn inability to delay gratificationThe preference of immediate small rewards over

large, but more delayed rewardsDecision-making without consideration of

potential negative consequences

Support for Personality Theory of Drug Abuse

Why is this relevant? If we can identify factors that place

individuals at an increased risk for drug use/abuse, then we may be able to target these groups for prevention

Treatment based on this theory has yet to be developed in spite of evidence from research

Causes of Addiction:Environmental Behavioral

Classical Conditioning: Stimuli related to the addictive behavior become paired with the behavior

Further contact produces conditioned response Operant Conditioning: Past addictive behavior

produced positive consequencesFuture use in presence of discriminative stimuli Addictive behavior is more rewarding than

alternatives

Expectancy Theory From past experience with substances, one

develops an expectancy about what the substance can do for them

Self-medication hypothesis

Support for Environmental Explanations of Addiction Untreated Heroin recovery (Robins,

1975)Research on 451 Vietnam veterans who had

been addicted to narcotics in during the warOnly 14 percent became re-addicted after their

returnEnvironmental cues for addiction no longer

active

Heroin overdoseIn the presence of heroin cues, body has

compensatory reaction (Falk, 1983)If drug taken out of typical environment, body

does not prepare for drug that comesIf no drug taken in typical environment, body

prepares for drug that never comes

Causes of Addiction:Diathesis/Stress Model

Certain people, due to a variety of biologically-based factors (genetics, neurocognitive functioning, stress response), may be predisposed (diathesis) to developing an addiction to something, be it alcohol, heroin, gambling, sex, shopping, or on-line computer services. They could go through their entire lives never developing any kind of addiction. On the other hand, if the right stressor, or combination of stressors, affects the person at a critical time, the person may be more inclined to develop an addiction.

Tracing the Neurobiological Roots of Addiction

Neural Circuits Involved in Establishing Addiction

Role of the nucleus accumbens Role of the orbitofrontal cortex

Figure 11.1 Extended amygdala.Lambert and Kinsley: Clinical Neuroscience, Second EditionCopyright © 2011 by Oxford University Press, Inc.

Figure 11.3 Two dopamine pathways in the brain.Lambert and Kinsley: Clinical Neuroscience, Second EditionCopyright © 2011 by Oxford University Press, Inc.

Tracing the Neurobiological Roots of Addiction (cont.)

Neurochemistry of Addiction Dopamine: Primary fuel of addiction Potential role of acetylcholine

Tracing the Neurobiological Roots of Addiction (cont.)

Craving Response Craving as a conditioned response Neural components of the craving

response

End

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