Nicotine is notoriously addictive, to the extent that the global market for nicotine cessation in 2021 was valued at an estimated $23 billion. Alcoholism is so insidious that those who are severe alcoholics can die if they go cold turkey.
Yet marijuana — the most popular psychotropic drug after alcohol — does not have the same stigma surrounding addiction. In stoner culture, the idea that marijuana is addictive in the same way as other famously addictive drugs is played for laughs, as seen in the 1998 stoner comedy "Half-Baked."
Yet as an increasing number of jurisdictions legalize marijuana for recreational use, some psychologists and treatment centers have begun to question the conventional wisdom surrounding marijuana's purported non-addictive status. The question resurfaced in July when a new study was published in Lancet Psychiatry suggesting that it is, and that observation of cannabis addiction may be linked to an increased potency in marijuana worldwide.
Unlike alcohol and nicotine, there are also medical uses for marijuana — pain management, help managing a sleep disorder, anxiety, or lessening the tremors in Parkinson's disease, just to name a few. Indeed, this is part of the driver behind legalizing recreational weed, which 19 states have already done. Then there are the economic benefits; one study predicted that cannabis legalization could result in $128.8 billion in tax revenue, and an estimated 1.6 million new jobs. The shifting political narrative has made marijuana a friendlier, more accessible drug, and perhaps contributed to notions of it as fairly benign. And even if it is addictive, it clearly isn't addictive in the same way as, say, cocaine or opioids, which are so addictive as to compel those in their thrall to steal, lie, or behave violently to acquire these substances.
In the field of mental health and addiction, Norton said that it is a "very settled question" that marijuana is addictive.
In the aforementioned Lancet study, the study's authors found a connection between potency and dependency. Specifically, they note that people who use higher concentrations of tetrahydrocannabinol (THC) — the main psychoactive compound in marijuana — are more likely to be addicted to marijuana and have mental health problems. That study drew eyebrow-raising headlines; CNN asked if "Highly potent weed" was "creating marijuana addicts worldwide."
Still, much of the controversy around this question lies in defining what one means by "addiction."
"The word addiction means so many different things to so many people, and that makes it kind of a challenging question in that sense," Dr. Aaron Norton, a mental health counselor who specializes in addiction, told Salon. Norton said many organizations "concur that marijuana is addictive — specifically, THC."
In the field of mental health and addiction, Norton said that it is a "very settled question" that marijuana is addictive.
"I think probably part of the confusion is that people, when they think of addiction, they sometimes think of more severe addiction presentations — like what we might see in a lot of people with opioid use disorder or with alcohol use disorder," Norton said. "They think about cannabis, and when they think about the difference in terms of the impact on society and on people and they think, 'well, it's not as bad as those other things.'"
Dr. Adrianne Trogden, a licensed addiction counselor, agreed, but further clarified the complexity of the word "addiction."
In the U.S., about three in 10 people who use marijuana have cannabis use disorder, the CDC estimates.
"While the word 'addiction' is used quite a bit, that's not actually a clinical diagnosable term — so in the medical world, we wouldn't diagnose somebody with an addiction, we'd diagnose with a substance use disorder," Trogden said. Trogden said that in their clinical practice and in the community, there is a "continuum of substance use."
"So there's people that have kind of experimented on one end of that continuum, and maybe used recreationally from time to time, all the way up to people that use all the time, every day, can't get through a day without it," she explained.
Indeed, therapists like Norton and Trogden often use the diagnosis of cannabis use disorder (CUD) when a client is struggling with cannabis use in a way that it is interfering with their relationships and everyday life. In the U.S., about three in 10 people who use marijuana have CUD, the CDC estimates.
According to the National Institute on Drug Abuse (NIDA), 9 percent of people who "abuse" marijuana will "develop an addiction to the drug in time." For people who start using marijuana during their teen years, that risk increases to 17 percent. One study found that CUD diagnoses have increased from 2.18% to 2.72%, in young people who live in states where recreational cannabis is legal.
"I see it all the time in my clinical practice, and I have clients who know that they're addicted to cannabis," Norton said. "So they come voluntarily to get help, because they're struggling to stop."
Dr. Carla Marie Manly, a clinical psychologist in California and author of "Joy From Fear," sees it too.
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"On a clinical level, I can certainly affirm that those who seek treatment for cannabis addiction often find it extremely difficult to eliminate the habit," Manly told Salon via email. "As with other self-soothing addictions (e.g., drinking alcohol, smoking cigarettes, etc.), many people find it tremendously challenging to 'kick the marijuana habit.'"
Biochemically speaking, THC isn't akin to opiates, opioids, cocaine, or other notoriously addictive drugs. So what precisely makes it "addictive"?
In essence, THC triggers chemical reactions in the brain that are associated with relaxation, euphoria and bliss. The more the brain is exposed to the THC by having receptors in the brain shut down, it will learn to only function at an optimal level when it's being exposed to THC. This can lead to feelings of restlessness and irritability when a patient isn't using marijuana.
Dr. Michael Kuhar further explained to Salon that THC attaches to endocannabinoid receptors in the brain, causing a physiological "high."
"Almost every addicting substance has a molecular site in the brain where it binds and causes some action," Kuhar said. "And the reason there's a molecular site in the brain is because there is an endogenous brain system that's like marijuana — it's not really marijuana, but THC can hook into that [endocannabinoid receptor] system."
THC, Kuhar explained, is also "self-administered," which further strengthens the case that marijuana is addictive. When a substance is self-administering, an animal in a laboratory is shown to voluntarily choose more of the substance instead of the placebo, which is usually saline.
"The animal presses the lever that has THC, he doesn't know that he's getting an injection, but he has a sensation and if he likes the sensation, he will press that lever again and again and again, and that is what we call THC self-administration," Kuhar said. "So that's the paradigm of drug self-administering, discovered in the late '70s, and it is now the gold standard for showing that something is addicting."
Research also supports the finding that ceasing use of cannabis can result in what is defined in the DSM-5 ( (Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition) cannabis withdrawal syndrome.
Norton said treatment looks different for each client, depending on many factors — such as if they see their use is a problem, and how it's impacting their life. Notably, there is Marijuana Anonymous, which is a 12-step program to help people maintain abstinence from marijuana.
As marijuana continues to be legalized in more states, mental health clinicians say more discussions around the possible adverse effects need to happen.
"So even though I see some good in medical cannabis, and I support it being legalized, like many things in life, there are awful drawbacks," Norton said.
Editor's note: This article was updated to clarify Norton's quote.
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