Wednesday, August 14, 2013

How does the brain change with addiction?


Personality Disorders of the Addicted

With advances in brain-imaging technology, medical experts can now conclude that addiction is not merely a defect in behavior or will, but a disease of the brain. Behavioral experts conclude that personality disorders can lead to substance abuse and can also result from substance abuse.




Until recently, clinicians treating substance abuse did not connect substance abuse disorders to personality disorders
. Now, substance abuse treatment usually involves the detection, management, and treatment of a person’s underlying personality pathology. A personality disorder is presented as persistent, unusual behavior relative to the cultural expectations for normal behavior, and it is usually observed during childhood or adolescence.


According to specialists Shelley McMain and Michael Ellery in a 2008 article in the International Journal of Mental Health and Addiction, persons with a personality disorder are impaired in two or more of the following behavioral functions: impulsivity, interpersonal functioning, affectivity, and cognition. McMain and Ellery, who found that the most common disorders among addicts are antisocial personality, borderline personality, and histrionic personality disorders, recommend “a thorough diagnostic assessment involving screening for personality pathology” for persons seeking treatment for addiction.


According to psychiatrist Raymond Anton, between 40 and 60 percent of persons dependent on alcohol have inherited the tendency to abuse alcohol. Most of these persons are male. Gene studies suggest that certain people are more susceptible to becoming alcoholics. Anton concluded,
Whether it is heredity (the genes we are born with) or an interaction between these genes and environmental events and/or between genes and substances themselves, there is no doubt that the genetic brain differences are likely to be at the root cause of addiction.




Brain Responses in Behavior

Scientists agree that alcohol and drugs affect the brain’s biochemical processes, altering the way neuroreceptors receive, process, and send information by overtaking the brain’s neurotransmitters or by overstimulating the brain’s pleasure center. Just as the brain connects the consumption of food and water as necessary for survival, the brain links alcohol or drugs to sustainment. The overuse of substances disrupts the brain’s normal biochemical balance and the brain’s mechanisms for controlling pain, anxiety, euphoria, and impulsiveness.


Because alcohol and drugs affect biochemical processes in the brain, they also impede the brain’s ability to control decision-making and judgment. The desire for the substance of choice becomes an all-consuming desire for the addict, and substance abuse becomes an intrusion into the brain from which the brain will never fully recover.


A person’s risk for addiction is linked to the reward and pleasure system in the brain. For many, intense euphoria is experienced when first trying a given substance, according to specialist Timothy W. Parker. The user’s brain cultivates a deeper attraction to the reward of the substance. In contrast, once the effects of the substance wear off, the person’s mood sinks to a severe low. The brain responds by again craving the substance, and the cycle continues, evolving into addiction. “Although they are motivated to take more of the drug to duplicate the original high,” Parker explained, “drug abusers will never again attain that intensity of pleasure. Clearly some reaction in the brain has reduced the effect of the drug. It is interesting that this occurs so rapidly; the brain is a quick study.”


This reduction of the effect of the substance characterizes the next stage of addiction. The user ingests higher doses of the substance, increasing tolerance. At this stage, withdrawal symptoms, which are the opposite of the high, persist if the user does not ingest the substance regularly. If a substance’s effect is relaxation and numbness, as with heroin, withdrawal symptoms manifest as restlessness, tremors, and pain. Withdrawal from a stimulant like cocaine includes fatigue and depression.


The final stage of substance abuse is recovery: the period after an addict undergoes treatment and is abstaining from the substance. Even when withdrawal symptoms have dissipated, the recovering addict remains extremely vulnerable to a reactivation of a craving for the substance, triggered by social cues and visual stimuli. Even in recovery the addict will continue to be plagued with a condition in the brain that blocks the “just-say-no” solution to substance abuse.


According to Anton in a 2011 article in the Journal of Law, Medicine, and Ethics, magnetic resonance imaging scans of the brains of alcoholics and nonalcoholics show chemical differences in the dopamine-activation part (pleasure center) of the brain. Alcoholic brains show much more activity than those of nonalcoholics when processing images of alcoholic substances. Anton further found that even during periods of abstinence, addicts experience a dopamine-receptor deficiency when challenged by alcohol stimuli, leading to pleasure cravings and, consequently, poor judgment.




Physical Brain Effects

Drugs and alcohol influence synaptic transmission in the brain and activate the release of an increased amount of dopamine into the brain’s neural circuit. Depending on the substance, two structures in the brain are affected: the ventral tegmental area (VTA) and the nucleus accumbens (NA). VTA neurons influence the NA, which is where dopamine is released. Most drugs either activate VTA or directly affect NA dopamine levels. The ethanol found in alcohol directly increases dopamine release in the NA.


As a person becomes addicted, the tolerance
to the substance of abuse increases. Physically, the brain changes to place controls (neuroadaptations) on how the substance affects dopamine release and changes to shut down NA receptors. The amount of dopamine released during ingestion of the substance subsides, causing the person to consume more of the substance to gain the desired level of pleasure. The brain also releases controls to regulate the addict’s emotions, activating moods of anxiety or depression as a sort of “antireward” system. The addict’s pursuit of pleasure facilitates higher doses of the substance, leading that person to potentially overdose.


Substance abuse leads to long-term brain changes. The neuroadaptations that the brain produces to control the release of dopamine and to regulate emotions remain with the addict even after treatment and abstinence. Addiction alters the prefrontal cortex of the user, causing the reduction in neuron activity in this part of the brain. Other parts of the brain release a neurotransmitter known as glutamate, which impairs the addict’s decision-making ability. Glutamate facilitates impulsiveness and a focus on immediate reward. Consequently, addicts often engage in reckless behavior, and rehabilitated addicts are prone to relapse when faced with substance-related stimuli. The amygdala, or memory part of the brain, is affected as well, enhancing emotional memories associated with being high, thereby making stimuli triggering these memories difficult for the addict to resist.




Treatment

In a 2011 editorial, the editors of Drug Week asserted that
Effective prevention and treatment of addiction requires a clear understanding of the complex brain mechanisms that underlie addictive behaviors, and research has provided a fascinating view of how substance abuse hijacks neuronal circuits involved in reward and motivation and causes profound and persistent changes in behavior.


Critical to effective treatment is understanding how substance abuse changes the brain over time. According to Parker, an estimated 90 percent of treated addicts relapse. Many addicts benefit from initial treatment, but clinicians need to better understand how these addicts can remain in recovery that lasts a lifetime.


Central to the Alcoholics Anonymous (AA) approach to treatment, for example, is the notion that the alcoholic has no power over his or her addiction. Assuming that addiction is a chronic life-long condition and that the addict’s brain cannot be cured medically, AA treatment involves intervention, group therapy and support, counseling, and accountability.


Pharmaceutical companies are seeking to develop pharmacological cures for addiction. With advances in neuroscience come new pharmaceutical treatments. Some treatments have been designed to make a person physically ill if they ingest a particular substance. Other treatments act as weaning mechanisms. Generally, drug treatment taps the brain’s natural dopamine regulators, the brain’s inhibiting mechanism (gamma-aminobutyric acid), and the brain’s excitatory mechanism (glutamate).


As pharmacologists seek to leverage pharmaceutical breakthroughs to develop remedies for substance abuse, skeptics insist that treating substance abuse with substances will not offer lasting cures. Suggesting that there is more to beating addiction than physically treating the brain, many people warn that the spiritual element of recovery should not be dismissed.




Bibliography


Anton, Raymond. “Substance Abuse Is a Disease of the Human Brain: Focus on Alcohol.” Journal of Law, Medicine, and Ethics 38.4 (2010): 735–44. Print.



McMain, Shelley, and Michael Ellery. “Screening and Assessment of Personality Disorders in Addiction Treatment Settings.” International Journal of Mental Health and Addiction 6.1 (2008): 20–31. Print.



Simon, David, and Deepak Chopra. Freedom from Addiction. Deerfield Beach: Health Communications, 2007. Print.



Westreich, Laurence M. Helping the Addict You Love. New York: Simon, 2007. Print.

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