The Biology of Addiction in the Brain

The Biology of Addiction in the Brain

By

Darryl Calloway

Dr. John Redmond

Walden University

February 20, 2011

Abstract

There are an alarming high number of individuals that are now receiving some form of treatment for drug addiction. Drug addiction is now being diagnose as a sever disorder. More and more research is reveling a correlation between the drug addiction and the brain. We will focus upon the biological affect of drugs, identify the five major classes of drugs, and explain how the brain is affect by certain drugs. In addition, the paper will define addiction and attempt to explain the relapse process

Introduction

Drug addiction is when a person has loss control over the amount they use, the amount of money they spend, or loss of control over behavior. Individuals that are addicted to drugs will encounter and experience many negative consequences because of their drug use (social, financial, legal, health, and employment), despite all of their problems addicted individuals will continue to use. Hyman (2005p 1414) postulated, "Addiction is defined as compulsive drug use despite negative consequences. The goals of the addicted person become narrowed to obtaining, using, and recovering from drugs, despite failure in life roles, medical illness, risk of incarceration, and other problems".

The National Survey on Drug Use and Health (Substance Abuse and Mental Health Services Administration (SAMHSA, 2007) estimated that 22.6million Americans 12 years of age or older, or 9.2% of the population, can be considered to have a substance abuse or dependence disorder (including alcohol or illicit drugs)" Feltenstein and See (2008 p. 261). According to the statistical data he U.S. Drug Enforcement Administration (USDEA) (2010) received from The National Institute on Drug Abuse (NIDA) over five million Americans suffer from drug addiction.

Due to severity of addiction, it is therefore, necessary that researchers extend beyond the old and narrow view about addiction that "addiction is a choice" and all that the addict needs to do is to stop using. By exploring addiction from a biological aspect, clinicians could provide more effective treatment for addicted. Gould (2010 p.5) hypothesized "addiction manifests clinically as compulsive drug seeking, drug use, and cravings that can persist and recur even after extended periods of abstinence.

Gould (2010 p.5) further postulated, "Addiction from a psychological and neurological perspective, addiction is a disorder of altered cognition". Exploring addiction cognitively allows researchers to learn where and how addiction develops in the human brain. Gould (2010 p.5) postulated "the brain regions and processes that underlie addiction overlap extensively with those that are involved in essential cognitive functions, including learning, memory, attention, reasoning, and impulse control".

Furthermore, Gould (2010 p.5) postulated that a continue use of drugs causes a cognitive shift in the brain which contributed to an addicted individual to seek the use of drug regardless of the negative consequences. Feltenstein and See (2008 p. 262) posited their theory of disequilibrium in brain reward systems based on animal models of addiction. "Drug use produces disequilibrium in brain reward systems for which the individual all static processes, or the ability to achieve stability (or homeostasis) through change, cannot be maintained" Feltenstein and See (2008 p. 262). From this study we can conclude that drug use causes the brain to shift and looses its equilibrium.

Feltenstein and See (2008 p. 262) quoted the theory of Koob and Le Moal (1997) where they have suggested that "continued exposure to the abused drug results in a pathological shift of the drug user's hedonic set point and a state of dysregulation of brain reward systems that result in loss of control over drug intake and compulsive use". Studies have shown that many abused substances can reshape the communication pathways between neurons (synaptic plasticity) Gould (2010 p.6)

Part of the Brain Associated with Addiction

Amygdala forms part of the limbic system and is an almond-shape set of neurons located deep in the brain's medial temporal lobe. According to Pinel (2009), the amygdala is involved in the processing of emotions. Kalivas and Volkow (2005 p. 1404) presentation revealed that dopamine released in the accumbens is required for the drug high and for the initiation of addiction. "The dopamine terminal field plays a major role in acute drug use. Dopamine release is increased during habitual drug seeking and where dopamine receptor antagonist infusions impair this behavior" Goldstein, Craig, Bechara, Garavan, Childress, Paulus, and Volkow, (2009 p.5).

An addicted seeking to use drugs was due to a triggering effect that caused stimuli to stay connected with using. Goldstein et al (2009 p.3 by disconnecting the ventral-dorsal striatal loops on drug seeking rats Goldstein et al (2009 p.3greatly and selectively decreases such habitual cocaine seeking by the rats.

Hyman (2005p 1415) conducted some extensive work that included pharmacological, lesion, transgenic, and microdialysis studies. According to Hyman (2005p 1415), "the rewarding properties of addictive drugs depend on their ability to increase dopamine in synapses made by midbrain ventral tegmental area neurons on the nucleus accumbens, which occupies the ventral striatum, especially within the nucleus accumbens shell region "Ornstein et al. (2000 p. 124) findings implicated that amphetamine and heroin abuse can lead to cognitive deficits through lasting effects on cortico-striatal circuitry".

The research of Volkow et al. (1997) was used to support the finding of Ornstein et al. Volkow et al. (1997), suggested that "the response to stimulants such as methylphenidate in cocaine abusers, as well as by other work suggesting significant cerebral hypoperfusion in the periventricular, frontal and other neocortical regions following cocaine abuse Ornstein et al. (2000 p. 124). Studies conducted by Sullivan (2011) have shown that cannabinoids negatively affect the functioning of the hippocampus, which, belongs to the limbic system and plays important roles in long-term memory. Sullivan (2011 p.132) postulated that the receptors