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Saturday, January 15, 2011

Darwinian Dependency?

Drug addiction is most certainly a worldwide epidemic. In fact, the use of drugs has reached all-time highs. In the United States alone, figures stagger the imagination. The National Institute of Drug Abuse reports that estimates of the total overall costs of substance abuse in the United States—including health- and crime-related costs as well as losses in productivity—exceeds half a trillion dollars annually. This includes approximately $181 billion for illicit drugs, $168 billion for tobacco, and $185 billion for alcohol.

Unintentional fatal drug overdoses in America nearly doubled from 1999 to 2004 and were the second leading cause of accidental death in 2004, behind only automobile crashes, according to the Centers for Disease Control. Researchers believe the increasing misuse of prescription drugs by those ages 15 to 24 accounts for the majority of the statistic.The CDC attributes the 62.5 percent rise in drug overdose deaths between 1999 and 2004 to a higher use of prescription painkillers and increasing numbers of overdoses of cocaine and prescription sedatives.

Very often, the treatment of addiction simply works to alleviate the symptoms of addiction, dealing with overcoming the physiological dependence and working through withdrawal symptoms as the body readjusts to a non-dependent state of homeostasis. Treatment and prevention programs should also consider that it is not just the physiology of addiction that begs attention. Enter Mr. Darwin.


Drives For Fitness and Viability

Tammy Saah reports, "It (addiction) is not just a pharmacological reaction to a chemical but a mode of compensation for a decrease in Darwinian fitness. (JL Falk, "Drug Abuse as an Adjunctive Behavior," Drug Alcohol Depend, 1998) There are three main components involved in substance addiction: developmental attachment, pharmacological mechanism, and social phylogeny including social inequality, dominance, and social dependence. (DH Lende, EO Smith, "Evolution Meets Biopsychosociality: An Analysis of Addictive Behavior," Addiction, 2002) The chemical changes associated with fitness and viability are perceived by mammals as emotions, driving human behavior."

Drug addiction causes a falsified sense of increased fitness and viability (continuing effectiveness). Evolution would support that mammals perceive gains in fitness and viability as emotions that drive human behavior.(DM Buss, "The Evolution of Happiness, Am Psychol,. 2000) For example, mammals would feel euphoric only during times where fitness levels were high, the euphoria being indicative of survival and not a modern conception of the elation of "happiness." Remember the old sage of nature? Survival of the fittest.

Dopaminergic and serotonergic systems, both of ancient origins, mediate human behavior. Positive emotions, such as euphoria and excitation, motivate humans towards increased gain and a fitness state. Some see a drug as a means to elicit these positive emotions. Also, negative emotions (pain, fear, stress, anxiety, etc.) have evolved in mammals to allude to even the slightest, most harmless potential indicator of a more serious problem. Often a person seeks help for escape from these negative emotions through drugs.

Today, people seek drugs to boost positive emotions and to eliminate negative emotions on a regular basis.

The New York Daily News (2003) published an article titled "We Need a War Vs. Legal Drugs."It suggests America is too drug dependent and begins by noting that from 1998 to 2002, sales of anti-depressant medications increased 73% to more than $12 billion, while analeptics, drugs like Ritalin and Adderall that stimulate the central nervous system, increased 167%. These figures were according to IMS Health, a pharmaceutical information and consulting company.

No doubt, modern drug prescriptions save millions of lives. The question is: At what price of dependency? For instance, the United States has even been dubbed the Prozac Nation. It is unlikely the $25 billion pharmaceutical industry supplying those antidepressants wants people to question the effects (for example, a rise in suicide rates) of taking a magic bullet pill to make anxiety and depression go away.

Yet, if a person administers a drug continuously and he becomes addicted to its false promises of fitness and viability, the brain becomes dependent on the drug. Without the drug, the person experiences withdrawal symptoms as the brain attempts to deal with the chemical changes.
Evolution and Changes

In ancestral environments, there was often a limited amount of drug resources for distribution, meaning there was little overactivity of salient (wanting) behavior (And, of course, less addiction). But, in a modern environment, similar limitations do not exist, and people are exposed to excessive amounts of drugs. Since human bodies are not wired to adapt to these changes, people now are much more vulnerable to developing addictions. (RM Nesse, "Psychoactive Drug Use in Evolutionary Perspective," Science, 1997)

According to Saah, "Modern environments include medical and social technologies that bring comfort and longer living than was experienced in ancient environment, so much of modern human emotion does not serve the same function as was evolutionarily performed." (Tammy Saah, "The Evolutionary Origins and Significance of Drug Addiction," Harm Reduction, June 29 2005)

While modern drug addiction indicates a false sense of fitness (improved survival), the motivation to consume the drug takes precedence even if the abuser realizes that gains in fitness are false.

The appetite for a drug may also override the drive to consummate, causing a drastic decrease in viability. The addict's emotional systems are now concentrated on drug-seeking rather than on survival. (J Panksepp, B Knutson, J Burgdorf, "The Role of Brain Emotional Systems in Addictions: A Neuro-evolutionary Perspective and New 'Self-report' Animal Model," Addiction, 2002)


Opioid addiction is rampant. Opioids are believed to mediate the consumption of reward, with opioid addiction following a well-defined route:

1) First ensues as a pleasure-seeking behavior, 

2) Tolerance to the opioid builds and pleasure resulting from drug use reduces, yet use is increased in an attempt to regain the hedonic pleasure, and 

3) Withdrawal may occur with a cessation of the opioid substance differing from withdrawal from psychostimulants, but also leading to negative emotions.  


Drug addiction not only causes various health problems but also abolishes negative emotions, such as pain. This could even shut off defense mechanisms. Even while considering genetic causes for addiction, one must admit it is usually caused by a combination of both external and internal stimuli. Can a person be pre-disposed to addiction? Yes. But, environmental and emotional stimuli may act as a catalyst towards the state of actual substance addiction.

The human brain is most likely motivated by a reward system; thus, an initial "like" for a substance leads to the insatiable "want" that correlates with abuse. Saah reports, "Although there has been a distinction made between a possibility of a reward-based abuse and a salience-based abuse (craving in which stimuli reinforces itself)*, it may be possible to see a combined effort of the two proposed systems working towards eventual drug addiction." (Tammy Saah, "The Evolutionary Origins and Significance of Drug Addiction," Harm Reduction, June 29 2005)

* For example, anti-drug agencies previously used posters with images of drug paraphernalia as an attempt to show the dangers of drug use. However, such posters are no longer used because of the effects of incentive salience in causing relapse upon sight of the stimuli illustrated in the posters.

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