04/18/2016 11:51 am ET Updated Apr 19, 2017

What Marijuana Can Teach Us About Addiction

When people think of the ravages of addiction, they tend to imagine needles in arms, broken bottles, flickering crack torches and trembling hands -- not someone smoking a joint in front of the TV. But marijuana can be addictive, too -- and understanding why helps explain how our drug policy has become so counterproductive.

The problem begins in the history of the way we define addiction. In the 70s and 80s -- at least in science and medicine -- addiction was conceptualized primarily as a physical problem. You took a drug, you liked it, but over time tolerance made your need for more escalate. Soon, you couldn't function without getting sick if you didn't have it. This paradigm was based on heroin and alcohol addictions -- both of which involve significant tolerance and a severe withdrawal syndrome.

But the idea that tolerance and withdrawal matter most didn't quite fit marijuana or cocaine. While people who are trying to stop these drugs can certainly become irritable and crave them, they don't typically puke, shake, sweat and otherwise physically show extreme signs that their need isn't "just in their head." Consequently, in the days of leisure suits and key parties, both marijuana and cocaine weren't considered particularly addictive. Indeed a Scientific American article in 1982 claimed that powder cocaine wasn't any more addictive than potato chips.

Of course, as we soon found out with the advent of crack, emphasizing tolerance and withdrawal was not such a great way to define addiction. Any definition of addiction that makes the intense craving associated with smoking cocaine and the compulsive behavior that follows "merely psychological" addiction clearly doesn't suffice. We also know a lot more about the potential for potato chips to be addictive.

Moreover, even in addictions where physical withdrawal is obvious, it turns out that it's not the core of the problem. This can be seen by examining an experience that's all-too-common among people who have experienced addiction: relapse. Most people who have kicked drugs make multiple attempts before succeeding.

In my case -- and this is a common story -- I never relapsed while I was suffering physical withdrawal from heroin. I gritted my teeth and shook through the nausea and diarrhea at least six times, unhappily, but without all that much difficulty. Until I finally kicked got into recovery, however, what always happened was this: when I started feeling good, a few weeks or months after stopping, I'd decide that I could handle "just one." I'd soon find myself re-addicted.

I had little tolerance and no physical withdrawal symptoms by the time I relapsed -- the rapid loss of tolerance is why relapse is so strongly linked with high risk of overdose death, in fact. Instead, my problem was in my thinking and desires, not in the feeling of illness. And it turns out that this psychology -- compulsive behavior that continues despite ongoing negative consequences -- is a far better way to define addiction and is far more important in determining outcomes.

Psychology also explains why marijuana -- although less addictive than cocaine or heroin -- can still be addictive for some. Indeed, studies find that about 10 percent of marijuana smokers become addicted to it. They smoke compulsively and continue even when doing so is clearly detrimental.
So why does addiction occur, if it's not down to tolerance and withdrawal?

Basically, addiction is a learning disorder that develops when the brain regions that normally motivate us to fall in love, parent and survive physically become misdirected to prioritize a drug or another experience. This happens when people learn that the drug or experience allows them to cope better -- at least at first. As a result, any experience that is pleasurable, distracts you from your problems or creates a sense of comfort and connection can be addictive in some cases. Highly addictive drugs and activities are more compelling, distracting or consistently (at least at first) pleasurable than those that are less addictive.

Consequently, alcohol and heroin are more addictive than marijuana not only because they produce worse withdrawal symptoms -- but more importantly, because they are better at allowing emotional escape. Both heroin and high doses of alcohol are more numbing than marijuana-- and both are also far less likely to derail into a "bad trip" that exaggerates your thoughts about your problems, rather than freeing you from them. Cocaine, too, is more addictive than marijuana, because it also produces more numbness and escape.

In contrast, psychedelics like LSD are less addictive. Even though the psychedelic experience is more intense than smoking pot, these drugs tend to magnify your problems rather than minimizing them. (Indeed, this is part of why psychedelics may help people quit other addictions: they help people realize that their other drug use is problematic, rather than productive).

When we understand that addiction is coping behavior that goes awry, several key points become clear. One is that the problem doesn't lie in the substance alone -- it lies in the relationship the user has with it and this cannot be solved simply by taking the drug away. Most of the time, exposure doesn't develop into addiction. When it does, other factors are involved.

In the case of marijuana addiction, around 90 percent of those affected have another psychiatric condition, commonly alcoholism, attention deficit/hyperactivity disorder (ADHD), anxiety disorders, personality disorders or depression. Around 2/3 have experienced serious childhood trauma. Many feel a general sense of emptiness and purposelessness in their lives.

Marijuana addiction can be trickier than other addictions in part because its consequences are less extreme. This is usually a good thing: it means that marijuana problems are not linked with violence and are less likely to destroy families and lead to unemployment or prison than many other drugs are. Ask the parent of anyone who has an opioid addiction or the spouse of any alcoholic if he or she would prefer having a loved one with a marijuana addiction instead -- rarely will anyone say no.

However, this also means that it may be hard for users to recognize that weed is a problem. A lost promotion is much easier to rationalize away than getting fired; having relationship problems is less obvious than getting divorced and marijuana does not usually lead to homelessness or hospitalizations for overdose -- let alone death. Smaller losses are hard to pin down -- and therefore, marijuana addiction can be insidious.

When we understand the real nature of addiction, we can do a better job of fighting it -- no matter what substance is involved. In the case of marijuana, this means recognizing that the harms of addiction, while subtle, are real -- and shouldn't be dismissed because they are psychological. Indeed, dismissing the importance of psychology in addiction and refusing to look at why people seek compulsive chemical escape is a critical part of why our drug policy continues to fail.

This post is part of a series produced by The Cannabis Science and Policy Summit (New York City, April 17-18). The Summit is a discussion of what is happening, what is likely to happen, and what should be done in the world of cannabis legalization. For more information about The Cannabis Science and Policy Summit, visit