By Pat Anson, PNN Editor

With the federal government on the verge of rescheduling cannabis as a less dangerous drug, and 38 states and the District of Columbia already allowing its medical and/or recreational use, it seems likely we’ll be hearing a lot more about cannabis use disorder.

A case in point is a large study, recently published in JAMA Network Open, that calls on primary care physicians to start screening all patients for cannabis use disorder (CUD).  It’s estimated that about 14.2 million Americans have CUD, a number that’s expected to grow as legal cannabis becomes more widely available.

The study found that 17% of primary care patients reported using cannabis in the last three months, usually to manage pain and other symptoms. Researchers say over a third of them (34.7%) used cannabis so frequently they were at moderate to high risk of CUD.

"Given the high rates of cannabis use, especially for symptom management, and the high levels of disordered use, it is essential that health care systems implement routine screening of primary care patients," wrote lead author Lillian Gelberg, MD, from the UCLA David Geffen School of Medicine.

“This group could benefit from a primary care clinician–based brief intervention to prevent those at moderate risk for cannabis use disorders from developing more serious CUD and to evaluate and refer high-risk users for possible addiction treatment.”

What is cannabis use disorder and how is it assessed? For the UCLA study, researchers used a screening tool known as ASSIST (Alcohol, Smoking and Substance Involvement Screening Test) that was originally developed by the World Health Organization and then modified to include cannabis.

Patients were asked if they’ve used cannabis in the last three months. If they said “yes,” five more questions were asked to assess why they use cannabis; how often they use it; if they’ve experienced tolerance or withdrawal; if they’ve tried unsuccessfully to reduce or stop using cannabis; and if it has interfered with any aspect of their lives.

Answer “yes” to one or two of those additional questions and a patient could then be diagnosed with CUD, even if they’ve used cannabis safely and responsibly for years. Their doctor could then select from dozens of diagnostic codes for CUD, ranging from cannabis dependence and intoxication to psychosis and hallucinations. All of the codes are billable for the doctor, so there is an incentive to use them.

Critics say this way of diagnosing people with CUD is fraught with problems, not unlike the way many pain patients have been diagnosed with opioid use disorder and forced into addiction treatment.

“This is my take too,” says Paul Armentano, Deputy Director of NORML, which advocates for full marijuana legalization. “Given that more than three-quarters of the (UCLA) cohort acknowledged consuming cannabis products ‘to manage symptoms,’ it’s hardly surprising that many if not all of these respondents would also report long-term regular use of the substance, as well as other criteria that overlap with signs of so-called cannabis use disorder.”

Armentano says several studies have documented declines in CUD, even after states legalized cannabis use.  

“To date, not a single legalization state has ever repealed or even rolled back their marijuana laws. This speaks to the reality that these regulations are working largely as intended and that the majority of those who consume cannabis do so in a responsible manner that poses little risk to either themselves or to others,” Armentano said in an email. 

In Washington State, one of the first states to legalize recreational cannabis, a recent study estimated that one in every five primary care patients had CUD, with 6.5% having moderate to severe CUD. Like the UCLA study, researchers said their findings underscore “the importance of assessing patient cannabis use in clinical settings.” 

“Knowledge of patient use provides an opportunity to discuss risks and limited benefits of cannabis use and potentially safer treatment alternatives for those using cannabis for medical reasons. For patients with higher risk cannabis use (eg, daily), psychometrically valid brief assessments for (diagnostic) symptoms of CUD can identify and gauge CUD severity,” they concluded. 

CUD Medications in the Pipeline

Treatments for CUD are currently limited to counseling and cognitive behavioral therapies such as meditation. Unlike opioid use disorder, there are no FDA-approved pharmaceutical treatments for CUD. That could soon be changing, as more drug companies recognize the potential value of CUD medication to their bottom lines.  

Indivior, the maker of Suboxone and Subutex for treatment of opioid use disorder, is conducting clinic trials on a synthetic drug -- called AEF0117 – that is designed to treat CUD by inhibiting a cannabinoid receptor in the brain that makes people feel “high.”

Indivior bought the worldwide rights to AEF0117 from a French pharmaceutical company for $100 million — which tells you how much value they think the drug could have. Indivior executives call AEF0117 “a unique opportunity to address a growing unmet public health need.”

“We have tested over a dozen potential treatment medications in our Cannabis Research Laboratory, and this is the first to decrease both the positive mood effects of cannabis and the decision to use cannabis by daily smokers,” said Margaret Haney, PhD, a professor of neurobiology at Columbia University who supervised the trials for Indivior.

According to ClincalTrials.gov, over a hundred clinical trials are currently underway or recruiting participants for a variety of potential CUD therapies. Most are treatments that already exist for other conditions and would be repurposed for CUD. One is gabapentin, a nerve drug currently used to treat seizures, shingles and pain. Other treatments being tested for CUD include transcranial magnetic stimulation, high blood pressure medication, and drugs used to help people stop smoking tobacco. 

Another anecdotal sign about the growing awareness of CUD can be found in the Federal Register, which has received over 17,000 comments so far about the Justice Department’s proposal to reclassify marijuana as a less restrictive Schedule III substance.

Nearly 700 of the comments mention CUD, with many containing boilerplate language claiming that “1 in 3 past year marijuana users met the clinical criteria for Cannabis Use Disorder.”

That theme is widely promoted by the addiction treatment industry, which maintains there is no clinical evidence “that the therapeutic benefits of medical cannabis or medical marijuana outweigh the health risks.”

There are currently no established medical guidelines or a “standard of care” that specifically address how to screen for CUD. But with cannabis use growing and healthcare providers coming under scrutiny for how they deal with substance abuse issues, future guidelines that require doctors to screen for CUD may be inevitable.

“How much longer will clients, families, social workers, and other mental health clinicians continue to be shortchanged by this situation? The time is well overdue to undertake formal cannabis use screening with well-established instruments during the mental health intake evaluation process, especially with adolescents and young adults,” wrote Jerrold Pollak, PhD, a clinical neuropsychologist, in Social Work Today.

One of the biggest hurdles for routine CUD screening may be patient reluctance to discuss their cannabis use. A survey of older U.S. adults found that less than 40% had discussed their cannabis use with a healthcare provider. Many fear being dropped by their doctor or being cut off from medication if they disclose that they’re using cannabis.