By Pat Anson, PNN Editor

About 10 percent of patients who use medical cannabis to relieve chronic pain develop more severe withdrawal symptoms, according to a new study that found most patients have only mild symptoms and remain stable after long-term cannabis use.

Researchers at the University of Michigan Medical School and the VA Ann Arbor Healthcare System followed 527 Michigan residents with chronic pain for two years, asking whether they experienced any of 15 different withdrawal symptoms – such as craving, nausea, irritability and aggression - when they had gone a significant amount of time without using cannabis.

At the start of the study, most had only mild (41%) or moderate (34%) withdrawal symptoms, with 25% of the patients classified as having severe withdrawal.  Researchers say many patients were not even aware they experienced withdrawal, attributing symptoms such as fatigue and poor sleep to their underlying pain conditions, not to any dependence on cannabis.

"Some people report experiencing significant benefits from medical cannabis, but our findings suggest a real need to increase awareness about the signs of withdrawal symptoms developing to decrease the potential downsides of cannabis use, especially among those who experience severe or worsening symptoms over time," says lead author Lara Coughlin, PhD, an addiction psychologist at U-M Medical School.

After one year, about 13% of the patients experienced more withdrawal symptoms, with 8% reporting more severe symptoms after two years. People who were younger, smoked cannabis, used larger doses, and had poor mental health were more likely to have severe symptoms.

However, the vast majority of cannabis users did not experience more withdrawal symptoms, with those who reported mild symptoms likely to stay that way. About 20% of patients reported fewer symptoms after one year and 14% had fewer symptoms after two years. Older age and vaping were associated with lower odds of having severe symptoms.     

“The majority of participants remained in their initial withdrawal class throughout the 2-year study period, with the highest stability among those with mild withdrawal symptoms at baseline. Of those who transitioned to another symptom class, transitioning to milder symptoms was slightly more common than transitioning to more severe symptoms,” researchers reported in the journal Addiction.

“For the majority of patients, the current findings indicate that the severity of withdrawal symptoms are likely to remain stable over time.”

Poor sleep was the most common withdrawal symptom, followed by depressed mood, decreased appetite, craving, restlessness, anxiety and irritability. The study did not assess whether cannabis was effective for pain relief or what form of ingestion worked best.

Cannabis Not Perceived As Risky

Most Americans believe cannabis has less abuse potential than alcohol and many commonly prescribed anti-anxiety and pain medications, according to survey results recently published in the journal Addictive Behaviors.

Researchers at the University of Delaware and Michigan State University surveyed over 1,000 adults in 2019 about their views on cannabis products such as hemp, CBD, THC and marijuana. The vast majority felt cannabis products have a valid medical use and have less abuse potential than hydrocodone, oxycodone, Xanax and Valium.

“These results suggest that consumers perceive CBD as more like an over-the-counter pain reliever such as Tylenol or Advil and less like prescription opioids,” researchers found. “They perceive CBD and hemp as medicinal and as having little potential for abuse, making them an attractive replacement for addictive pain relievers.”

The researchers acknowledged that there is little clinical evidence to support these views, but blame the lack of studies on the federal government’s classification of marijuana as a Schedule I Controlled Substance, saying it has “severely limited research.”

A longtime critic of federal marijuana policy was not surprised by the survey findings.

“The overwhelmingly majority of Americans have long abandoned the federal government’s ‘Flat Earth’ position that marijuana is highly dangerous substance without any therapeutic efficacy,” said Paul Armentano, Deputy Director of NORML, a marijuana advocacy group.

“It is time for Congress to jettison this intellectually dishonest position as well and remove cannabis from the Controlled Substances Act in a manner similar to alcohol — thereby ending the existing state/federal conflict and permitting state governments, not the federal government, to be the primary arbiters of cannabis policy.”