The Essence of Addiction

The entire concept of addiction has suffered greatly from imprecision and misconception. In fact, if it were possible, it would be best to start all over with some new, more neutral term. The confusion comes about in part because of a now archaic distinction between whether specific drugs are "physically" or "psychologically" addicting. The distinction historically revolved around whether or not dramatic physical withdrawal symptoms occur when an individual stops taking a drug; what we in the field now call "physical dependence."
However, 20 years of scientific research has taught that focusing on this physical versus psychological distinction is off the mark and a distraction from the real issues. From both clinical and policy perspectives, it actually does not matter very much what physical withdrawal symptoms occur. Physical dependence is not that important, because even the dramatic withdrawal symptoms of heroin and alcohol addiction can now be easily managed with appropriate medications. Even more important, many of the most dangerous and addicting drugs, including methamphetamine and crack cocaine, do not produce very severe physical dependence symptoms upon withdrawal.
What really matters most is whether or not a drug causes what we now know to be the essence of addiction: uncontrollable, compulsive drug craving, seeking, and use, even in the face of negative health and social consequences. This is the crux of how the Institute of Medicine, the American Psychiatric Association, and the American Medical Association define addiction and how we all should use the term. It is really only this compulsive quality of addiction that matters in the long run to the addict and to his or her family and that should matter to society as a whole. Compulsive craving that overwhelms all other motivations is the root cause of the massive health and social problems associated with drug addiction. In updating our national discourse on drug abuse, we should keep in mind this simple definition: Addiction is a brain disease expressed in the form of compulsive behavior. Both developing and recovering from it depend on biology, behavior, and social context.
It is also important to correct the common misimpression that drug use, abuse, and addiction are points on a single continuum along which one slides back and forth over time, moving from user to addict, then back to occasional user, then back to addict. Clinical observation and more formal research studies support the view that, once addicted, the individual has moved into a different state of being. It is as if a threshold has been crossed. Very few people appear able to successfully return to occasional use after having been truly addicted. Unfortunately, we do not yet have a clear biological or behavioral marker of that transition from voluntary drug use to addiction. However, a body of scientific evidence is rapidly developing that point to an array of cellular and molecular changes in specific brain circuits. Moreover, many of these brain changes are common to all chemical addictions, and some also are typical of other compulsive behaviors such as pathological overeating.