Longtime users swear marijuana is a non-addictive herb you can quit any time—no problem. Rehab centers and government websites cite a long list of withdrawal symptoms that prove cannabis is a highly addictive and dangerous drug. Who’s right? The answer depends partly on the definition of addiction itself and on the complex interplay of brain pathways that creates a pattern of compulsive behaviors.
From a legal perspective, cannabis is clearly considered addictive. It’s firmly placed on the Drug Enforcement Administration’s Schedule I list of highly addictive substances, and government sponsored drug information sources offer a long list of symptoms of marijuana addiction and withdrawal.
That position is supported, not too surprisingly, by the recovery and rehab community, which lists marijuana withdrawal symptoms such as insomnia, gastrointestinal distress, chills and sweating as reasons for seeking medical detox and rehab services.
On the other side of the debate stands a sizeable community of people who use cannabis both for recreational and medicinal purposes, many of whom say cannabis products of all kinds are not addictive, and it’s possible to stop using them at any point—say, for a job that does drug testing—without feeling any physical or psychological effects.
In between are those who report feeling irritable, angry, ill or depressed after stopping cannabis, or who see a rebound effect of any conditions they may be treating with cannabis products.
The National Center on Addiction and Substance Abuse defines addiction as a “complex disease” characterized by “severe loss of control, continued use despite serious consequences, preoccupation with using, failed attempts to quit, tolerance and withdrawal.”
Associated with the notion of addiction are other terms such as substance use disorder, substance dependence, substance use syndrome, and substance problem, all aimed at pinning down various stages and aspects of addiction to drugs and alcohol.
For many people, the definition of addiction is physical dependence on a particular substance, such as heroin or alcohol. Stopping those kinds of substances throws the body and brain into crisis, with many well-documented and potentially serious withdrawal symptoms.
But many essential medications create a physical dependence, too—and stopping them can also produce that kind of withdrawal. For example, a person taking a potent antipsychotic drug can experience symptoms including seizures and heart arrhythmia if they stop suddenly, but that person wouldn’t be considered addicted to the medication.
Even though the compounds in cannabis bind to the body’s natural endocannabinoid receptors, research suggests that less than 10% of cannabis users develop a physical addiction. And if stopping cannabis cold turkey does produce symptoms, they tend to be relatively mild and brief.
If physical dependence that leads to withdrawal is the main criterion for defining addiction, then users who claim that marijuana isn’t addictive have a point—it isn’t equivalent to substances like heroin and alcohol, which do cause severe withdrawal syndromes. But addiction has other aspects besides physical dependence.
Recent studies on addiction and the brain suggest that compulsion, which explains a wide range of addictive behaviors, can also explain why some people become addicted to cannabis.
It’s possible to become addicted to many things, from computer games to exercise, to sex. These kinds of addictions have been labeled as “behavioral” to distinguish them from “substance” addictions, which are often assumed to also include physical dependence.
Underlying all of them is compulsion—a loop of responses that are activated by the relationships between the brain’s circuits for pleasure, memory and problem solving. This loop accounts for key parts of the classical definition of addiction: continuing the behavior despite negative consequences, failed efforts to quit, cravings for the desired substance, and preoccupation with getting it at all costs.
When the brain receives input that is perceived as pleasurable, it responds with a surge of dopamine to a small area called the nucleus accumbens. It doesn’t matter what the source of that pleasure might be—a drug; a behavior; an experience.
Once that burst of dopamine is triggered, the hippocampus, an area of the brain responsible for processing memories, lays down a memory of the event. After that, the amygdala encodes a specific response to that stimulus. For example, if a person uses cannabis and likes it, that pleasurable memory can lead them to use it again.
In addiction, another step takes place within this pleasure-reward loop to make the behavior compulsive; it’s not about merely liking a substance but craving it even in the face of negative consequences. Dopamine, the “feel good” chemical, also interacts with another neurotransmitter called glutamate, which is associated with learning and motivation. That adds another piece to the circuit—the drive to repeat whatever action produces that surge of dopamine.
The pleasure-reward learning process happens constantly in many circumstances. Without it, humans would never learn new things, achieve goals, or even survive. But addictive substances and behaviors cause a much faster and more intense surge of dopamine than normal—immediate satisfaction that the brain wants to repeat.
Those wanting and motivating factors cause users to seek out that feeling again and again, regardless of any negative consequences for doing so. And while they may want to stop, or try to stop, it doesn’t work for long because compulsion overrides other decision-making processes in the brain.
Fighting compulsion produces its own kind of withdrawal, which can have both psychological and physical aspects. People can feel anxious, depressed or angry without the object of their addiction. Relationships, appetite and sleep patterns can suffer too, and some individuals may need professional help to move past the addiction.
Can you become addicted to marijuana? That depends on how addiction is defined—and physical dependence is just one piece of the puzzle. When compulsion drives consumption and disrupts a user’s life, the answer may be yes.
Photo credit: S.Su