Dr. Hill: A big challenge is helping heavy users understand that cannabis use disorder is a real thing. It is hard for people to appreciate the risks that are associated with heavy use when they hear about the medical benefits and the recreational aspects of cannabis. There is also a relationship with dose and an increased likelihood of adverse effects with increased dose, which is important because of today’s higher potency levels and concentrates. Unfortunately, there also are no FDA-approved medications for cannabis use disorder or cannabis withdrawal.
CATR: You mention potency, and we’ve been reading how stronger levels of tetrahydrocannabinol (THC), the chemical compound that causes the high, can create severe withdrawal syndrome. Can you tell us more?
Dr. Hill: Daily use of potent cannabis is going to produce the most severe withdrawal symptoms. The potency of cannabis has skyrocketed in the last several years. THC potency today is about 12.9%, whereas in the 1960s, 70s, and 80s, THC content in cannabis was 3%–4% (ElSohly MA, Biol Psychiatry 2016;79(7):613–619). Concentrates, where people distill the plant down into very pure forms of cannabis, are another issue relative to withdrawal symptoms. With concentrates, THC potency levels can exceed 90%. Although there isn’t a lot of scientific evidence to support a dose-response curve, it seems—at least anecdotally—that increased doses or increased potency of cannabis leads to more severe withdrawal symptoms, or increased incidence of other adverse effects.
CATR: Let’s assume that I’m a heavy user. I’m not sure that I really want to stop cold turkey, even with a medication. As psychiatrists, what do we say and how do we deal with this type of patient?
Dr. Hill: Well, most people who come to my office with cannabis use disorder are being pushed in by their schools, their employers, their spouses, or their families. Oftentimes, it takes a lot of motivational interviewing to get them to understand that they need to make a change in their cannabis use. That often involves talking about things that they value that are in jeopardy, or that they’ve already lost. So, if people get to a point where they are willing to make a significant reduction, we will start with medications. But there also must be an understanding that it’s still going to be difficult for them to totally abstain. That gets to the issue of how, perhaps, it’s better for some of these patients to use quantitative urine testing, which tells you how much of a specific substance is present in a patient’s urine specimen. This gives us a tool that allows us to better track patients’ progress in reducing their use.
CATR: In terms of just talking patients through the process, do you have them quantitate the amount of use, and then give them a tapering schedule of cannabis to get down? What seems to work the best?
Dr. Hill: I don’t have a quantitative amount I suggest. I tell them to try avoiding using cannabis, and then we will start the medication if warranted. If they are taking a medication, people can dramatically reduce their use. The question becomes, is that sustainable? People who aren’t going to do well will manage a few days or even a week of reduced use, and then their use will creep back up, even while they are on the medicine. Some people can sustain it. If we have the medicine, and the patient is ready to do it, then we do it and try to use as little cannabis as possible. But I don’t talk about a taper schedule. Also keep in mind that cannabis use at the level of cannabis use disorder does not occur in a vacuum. There are often other issues that require attention, psychosocial stressors, pain, or psychiatric disorders like depression, anxiety, or ADHD. I often get referrals from other doctors when they discover that daily cannabis use may be contributing to the ineffectiveness of an antidepressant or a stimulant that they are prescribing.
CATR: You mentioned medications. So, what would you recommend for a pharmacological approach, either as part of managing cannabis withdrawal syndrome or as actual treatment?
Dr. Hill: Unfortunately, there are no FDA-approved medications now for cannabis use disorder, but there are other things that you can try. You can try an agonist approach. Dronabinol and nabilone are FDA-approved cannabinoids, and were shown in trials at Johns Hopkins to lessen withdrawal symptoms (Vandrey R et al, Drug Alcohol Depend 2013;128(1–2):64–70). Any practitioner can prescribe both cannabinoids, but chances are that they won’t be covered by insurance, and the drugs are expensive. Also, I think we need more evidence through studies that cannabinoids are truly effective as pharmacotherapy for cannabis use disorder. In terms of off-label medications, gabapentin had a very positive trial (Mason BJ et al, Neuropsychopharmacology 2012;37(7):1689–1698). In that study, administering 1,200 mg of gabapentin showed reductions in cannabis withdrawal symptoms.
CATR: What about N-acetylcysteine as an option for treating cannabis use disorder? We’ve heard there have been some positive studies here.
Dr. Hill: A study on N-acetylcysteine (Gray KM, Am J Psych 2012;169(8):805–812) showed reduction in cannabis use among adolescents. However, that finding in adolescents wasn’t replicated in adults, according to another study that just came out in Drug and Alcohol Dependence. But, from my perspective, if somebody has a therapist and the person’s other psychiatric disorders are being adequately addressed, then I am apt to try either N-acetylcysteine or gabapentin, largely because the side effect profiles are relatively favorable.