In stark contrast to the exaggerated fears portrayed over the past few decades, most people today consider cannabis to be relatively harmless. Weeds are less dangerous than some other drugs, but not without their risks.

In a study published January 5, my colleagues and I found that 59% of people who used medicinal cannabis for chronic pain experienced moderate to severe withdrawal symptoms if they stopped consuming weeds for hours or days.

Most US states have legalized cannabis for medicinal purposes and 15 have legalized it for recreational use. More and more people are using cannabis, especially older adults, and the perceived harm from using weeds is steadily decreasing. While many people report therapeutic benefits or enjoy recreational use of cannabis, it is important that people also understand the potential risks of cannabis use.

What cannabis withdrawal looks like

Cannabis withdrawal symptoms can include both physical and psychological experiences that occur when someone drops from a high level or remains without use for a period of time.

When people use cannabis regularly – say, every day or almost every day – parts of the brain depend on cannabinoids, the psychoactive chemicals in cannabis. Cannabinoids are produced naturally in the body, but at a much lower level than most cannabis products. Cannabinoid levels drop and withdrawal symptoms occur among those who do not use weeds for several hours or days. These include irritability, depressed mood, decreased appetite, insomnia, the desire or craving for cannabis, restlessness, anxiety, increased aggression, headache, shakiness, nausea, increased anger, strange dreams, stomach pain and sweating.

The symptoms of cannabis withdrawal usually go away within a week or two of stopping use as the body adjusts to its natural cannabinoid production. In contrast to withdrawal from some psychoactive substances – like alcohol – withdrawal from cannabis is not life threatening or medically dangerous. But it does exist. Withdrawal from cannabis can also be quite uncomfortable, and people can continue their cannabis use – even if they want to reduce it – just to avoid withdrawal.

Regular cannabis use can lead to addiction and withdrawal if a person stops using cannabis.
AP Photo / Ted S. Warren

How common are withdrawal symptoms?

To find out how common withdrawal symptoms are, my colleagues and I repeatedly surveyed 527 people over two years who were using medicinal weeds for chronic pain. We found that 59% of people who use medicinal cannabis for chronic pain had moderate to severe withdrawal symptoms. The most common symptoms were difficulty sleeping, irritability, and anxiety.

We also found that cannabis withdrawal symptoms were more severe in younger people, people with mental health problems, people with a longer history of cannabis use, and people who used it more often or in larger amounts. In addition, we found that smoking cannabis – instead of eating it or using it topically – correlated with worse withdrawal symptoms.

Our team also looked at how people’s withdrawal symptoms have changed over time. Most continued to have the same severity of withdrawal symptoms when they stopped using cannabis in the two years of the study, but about 10% – especially younger people – got worse over time. As with most addictive substances, reducing the frequency or amount of cannabis use can help alleviate these symptoms.

Our study looked at people who only use medicinal cannabis for pain. In another recent meta-analysis that spanned both recreational and medicinal uses, the researchers found that 47% of frequent cannabis users experience withdrawals.

Cannabis may not be the demon drug of Reefer Madness, but neither is it a miracle plant, with boundless advantages and disadvantages. As cannabis use increases in the United States, it is important for people to understand that regular use can lead to withdrawal and to know what those symptoms are.

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