However, nonspecialists (including many doctors) still tend to use an older perspective, now seen as outdated by experts. From their point of view, some drugs may be considered physically addictive — producing severe withdrawal — while others are psychologically addictive and only cause craving; those that are both are the hardest to quit.
In this view, the paradigm for addiction is heroin: the shaking, puking heroin junkie who can’t quit because the withdrawal sickness is impossible to bear. Because marijuana cessation is not linked with such severe symptoms, the drug isn’t seen as physically addictive. And considering that most people view physical addiction as uncontrollable, but psychological addiction as manageable with proper willpower, marijuana tends not to be regarded as addictive in general.
But virtually all addiction experts disagree with that stance. “The distinction is completely arbitrary. Psychological addiction occurs in your brain and it’s a physical change,” says Dr. Nora Volkow, director of the National Institute on Drug Abuse. Different brain processes may be involved in the psychological drive to take drugs and in the physical withdrawal symptoms when the drug is stopped — but both are brain changes.
As it turns out, the psychological drive is much more powerful than the physical experience of withdrawal. Cocaine, which also produces little withdrawal sickness but does create extreme craving, was once seen as nonaddictive — that was before America was introduced to crack in the 1980s. More than a century ago, Mark Twain summed up the essence of the problem, in reference to the addictiveness of tobacco: “Giving up smoking is easy,” he said. “I’ve done it thousands of times.”