Cannabis use disorder is now more prevalent than previously thought, with new research suggesting that as many as one in three users may become addicted — a sharp rise from earlier estimates that put the figure at one in ten.
A habit that spirals
Amy, an 18-year-old who asked to remain anonymous, knows the grip of dependence all too well. She had thrown a THC vape cartridge — known as a “cart” — into a public bin, only to retrieve it moments later as passersby stared. The following week she tossed it into a dumpster, desperate to break the cycle. She ended up lifting the entire garbage bag, digging through the mess to find it and take a grateful toke. “I’ve tried everything to stop,” she said. Rehab, therapy, giving carts away, making non-smoking friends, changing schools — nothing has worked. “Especially after the dumpster situation. That seriously scared me.”
Amy is one of more than 400,000 members of r/leaves, a Reddit community dedicated to quitting cannabis. Another member, Liam, a 33-year-old father, said the drug initially helped him quit alcohol and other harmful substances. “In a way I considered it a saviour,” he said. But after his first child was born, he could not shake the habit. “I’ve destroyed bongs, cut contacts with dealers, but it has been futile. Without cannabis I felt empty, as if there was nothing to life without it. And therefore I always came back.”
Shannon Keating, a Liverpool-based freelance writer, described her own battle. She started as a social user during the pandemic, when New York legalised recreational cannabis. Within a few years, her use had turned solitary and compulsive. She sold belongings to pay for weed, chose it over groceries, and experienced paranoia, disorientation and derealisation. Her wife noticed she had become “clumsy, inconsiderate, forgetful and aloof”. She tried restricting herself to evenings and weekends, moderation, breaks — nothing worked. “I couldn’t, wouldn’t, stop,” she wrote.
Why the risk has soared
The experts Keating consulted pointed to one crucial factor: the sheer potency of modern cannabis. Half a century ago, typical THC content was around 4%. Today, street cannabis averages about 20% THC, and dispensary concentrates can reach 95% THC. “The reason why people didn’t believe that cannabis was addictive,” said Dr Deepak D’Souza, professor of psychiatry at Yale School of Medicine and director of the Yale Center for the Science of Cannabis and Cannabinoids, “is because the cannabis that was available then, and the studies that were done to look at cannabis addiction, suggested that only one in 10 people developed cannabis use disorder. Newer studies are suggesting that one in three might have developed cannabis use disorder.”
THC — tetrahydrocannabinol — stimulates the brain’s reward system, releasing dopamine and creating a high. Heavy users who stop experience a sharp drop in dopamine, driving continued use. The risk of developing cannabis use disorder (CUD) is greater for those who start before age 25, use heavily, or have pre-existing mental health conditions or genetic predispositions. “We can see clear changes in the brain in heavy cannabis users which reflect the consequences of the brain being bombarded with THC over a period of time,” D’Souza added.
Dr Jonathan Caulkins, a drug policy researcher at Carnegie Mellon University and author of a 2024 study on changes in cannabis use, said there is a “persistent misunderstanding” about cannabis not being addictive. “We don’t need more research to know it’s a dependent-producing toxin,” he said. However, because many people use it without developing CUD, “lots of people know plenty of people who don’t become addicted”. His research found that “a significant share of current cannabis users, including those who use frequently, self-report the consumption interferes with their lives in some consequential way”.
According to the US Centers for Disease Control and Prevention (CDC), an estimated 30% of cannabis users will become addicted. CUD, as defined by the DSM-5 and the CDC, involves 12 months or more of continuing use despite negative physical, social or psychological effects, spending large amounts of time using or thinking about using, and repeated failed attempts to quit.
The rise in potency has been linked to serious health harms. There are growing associations between high-THC consumption and psychosis, particularly among younger users. Emergency rooms are seeing more cases of cannabinoid hyperemesis syndrome (CHS), a condition marked by severe vomiting and abdominal pain. Frequent use is also linked to memory loss and impaired executive function.
Dr Jack Wilson, a postdoctoral fellow at the University of Sydney’s Matilda Centre for Research in Mental Health and Substance Use, co-wrote the largest review ever conducted on the safety and efficacy of cannabinoids for mental health. It found no evidence that medical cannabis is effective in treating anxiety, depression or PTSD — three of the leading conditions for which it is prescribed. Since publication, Wilson has been accused of working for the pharmaceutical industry. “I find that funny,” he said, “not only because I’m not funded by any industry — but because cannabis is big pharma now, whether people like it or not.”
Social media often dismisses such findings as conspiracies funded by big alcohol or government propaganda. D’Souza pointed out that “one of the most important dynamics in substance use disorders is denial and rationalisation”. Caulkins noted the lasting cultural impact of films like Reefer Madness, which depicted marijuana users as deranged criminals. “People have a lot of distrust” when it comes to institutional messaging, Wilson said, “even though we know that drug use is a health problem. It’s not a criminal problem.”
The difficult road to recovery
Keating’s path to quitting began only after her doctor told her she needed 30 days weed-free before starting medication for newly diagnosed ADHD — mixing cannabis and stimulants is dangerous for the heart. “Even then, the only thing that helped me stop was the promise of another drug,” she wrote.
Stopping cold turkey proved brutal. She could not eat or sleep. Vivid dreams turned into night terrors. “I felt empty, like life would never be fun again.” But she eventually passed into what some call the “pink cloud” — a period of euphoric optimism in early sobriety. Months on, the pink cloud has faded, but quitting has transformed her life. She is crafting again, taking qigong classes, sewing, dancing and hiking. “The depression and anxiety I thought I was treating with weed has since lessened considerably.”
Marianne, 22, recently quit and experienced cannabis withdrawal syndrome (CWS), now included in the DSM-5. Symptoms — inability to sleep, night sweats, no appetite, irritability — were “really difficult” but eased after a few days. However, “feeling empty and emotionally flat can take weeks and months to go away”.
EB used cannabis regularly for more than 40 years and quit in her mid-60s. Her advice: “Get at the root of why you’re using in the first place. Deal with the pain. Once you deal with the pain, you don’t need the Band-Aid any more.” As a child she had wanted to play drums, but her father would not allow it. Now she plans to take lessons. “I love [EB] 2.0,” she said. When Keating told her that had been a childhood dream of hers too, EB replied: “It’s not too late for you to learn, either. We’re grownups now, and we’re in charge.”
UK context: a different legal landscape
While the conversation around cannabis addiction is global, the legal and social framework in the United Kingdom differs sharply from that in the United States. Cannabis remains a Class B drug under the Misuse of Drugs Act 1971. Possession can carry up to five years in prison, an unlimited fine, or both; supplying or producing carries a maximum of 14 years.
In November 2018, the UK government reclassified cannabis-based products for medicinal use as prescription-only medicines. Specialist doctors can prescribe them for severe epilepsy, multiple sclerosis and chemotherapy-induced nausea, but access remains limited and they are not available for general mental health conditions or as a recreational substitute.
Despite ongoing debates about decriminalisation or legalisation — with some pressure groups and politicians citing potential tax revenues and a public-health approach — the government has maintained its stance, emphasising the drug’s harms. The prevalence of cannabis use among adults in England and Wales has shown fluctuations, with some reports indicating a rise in recent years, particularly among younger adults.
For those seeking help in the UK, the NHS offers assessment, counselling and support groups for drug addiction, including cannabis. Private rehabilitation centres provide specialist programmes often using cognitive behavioural therapy and motivational interviewing. Peer support is available through organisations such as Narcotics Anonymous. Harm-reduction strategies — helping users reduce risks if they are not ready or able to quit — are also part of the support landscape.
The economic costs of cannabis addiction — healthcare, lost productivity, criminal justice — are difficult to quantify but significant. The impact on families and relationships is clear from the personal stories of those struggling to break free. As D’Souza noted, even if cannabis offers temporary relief from psychological distress, “it really doesn’t do much for the underlying condition”.