Showing posts with label drugs and the brain. Show all posts
Showing posts with label drugs and the brain. Show all posts

Thursday, April 15, 2010

Liking It Vs. Wanting It


The Joylessness of Drug Addiction.

Hedonism, the pursuit of pleasure for its own sake, is not really the answer to the riddle of drug addiction. The pursuit of pleasure does not explain why so many addicts insist that they abuse drugs in a never-ending attempt to feel normal. With compulsive use and overuse, much of the pleasure eventually leaches out of the primary dysphoria-relieving drug experience. This does not, however, put an end to the drug-seeking behavior. Far from it. This is the point at which non-addicts tend to believe that there is no longer an excuse—the pleasure has dribbled away, the thrill is gone—but even when addicts aren’t getting the full feel-good benefits of the habit, they continue to use.

And now we know why. Any sufficiently powerful receptor-active drug is, in its way, fooling Mother Nature. This deceit means, in a sense, that all such drugs are illicit. They are not natural, however organic they may be. Yet, the human drive to use them is all-pervasive. We have no real built-in immunity to drugs that directly target specific receptors in the limbic and cortical pleasure pathways. 

The act of “liking” something is controlled by the forebrain and brain stem. If you receive a pleasant reward, your reaction is to “like” it. If, however, you are anticipating a reward, and are, in fact, engaging in behaviors motivated by that anticipation, it can be said that you “want” it. The wholly different act of wanting something strongly is a mesolimbic dopamine-serotonin phenomenon. We like to receive gifts, for example, but we want food, sex, and drugs. As Nesse and Berridge  put it, “The ‘liking’ system is activated by receiving the reward, while the ‘wanting’ system anticipates reward and motivates instrumental behaviors. When these two systems are exposed to drugs, the “wanting” system motivates persistent pursuit of drugs that no longer give pleasure, thus offering an explanation for a core paradox in addiction.” 

The absence of pleasure does not mean the end of compulsive drug use. Researchers are beginning to understand how certain drugs can be so alluring as to defeat the strongest of people and the best of intentions. It certainly does not eliminate the pain of drug hunger, of craving, to know that it is physically correlated with “a pathological overactivity of mesolimbic dopamine function,” combined, perhaps, with “increased secretion of glucocorticoids.” For such a wide variety of drugs, exhibiting a wide variety of effects, the withdrawal symptoms, while varying by degree, are nonetheless quite similar. The key, as we have seen, is that the areas of the brain that control “wanting” become sensitized by reward pathway drugs.

Under the biochemical paradigm, a runaway appetite for non-stop stimulation of the reward pathway is a prescription for disaster. The harm is physical, behavioral, and psychological—as are the symptoms. Peer pressure, disciplinary difficulties, contempt for authority—none of these conditions is necessary for drug addiction to blossom. What the drug itself does to people who are biologically vulnerable is enough. No further inducements are required. 




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