Does Cannabis Interact with Antidepressants?
Cannabis can make people feel more relaxed, less stressed, and, of course, happier. So predictably, people experiencing depression or anxiety are much more likely to use cannabis — and more of it — than people not suffering from these conditions.
Of course, many people with these conditions also take prescription antidepressants. Consequently, it’s important for medical professionals and patients to be educated on potential interactions that could arise by combining the two.
Remarkably, despite years of research investigating links between cannabis use and psychiatric disorders, few rigorous studies have been published that closely examine how cannabis and antidepressants may interact. Robust searches of Google Scholar and the National Institutes of Health PubMed website produced few relevant studies. Even the National Institute on Drug Abuse (NIDA) website carries very little information on this topic.
Researchers from the Division of Child and Adolescent Psychiatry at the University of Connecticut Health Center conducted an extensive review of the limited scientific literature and published a report, Psychotropic Medications and Substances of Abuse Interactions in Youth. They noted — and I’m paraphrasing — that while one might presume combining psychoactive drugs and psychotropic medications would increase the chances of patients experiencing adverse effects, there have been (astonishingly) few reports documenting adverse effects arising from interactions between the two.
The University of Connecticut researchers explain why there may be so few reports: it’s possible adverse events are “relatively rare” or “do not happen.” Moreover, “newer psychotropic medications have a relatively high therapeutic index” — as a class of drugs, they are less likely to produce adverse interactions. However, they also noted that lack of recognition or awareness could be to blame, and patients experiencing adverse effects may resist disclosing their cannabis use for fear of stigmatization.
Nonetheless, it’s likely that newer antidepressants carry a low to moderate risk for interactions, while older antidepressants carry a higher risk. Characterizing the risk as “moderate,” RxList, an online index of drugs published by WebMD, advises patients who use cannabis to “be cautious” and “talk with [their] health provider.”
Risks of Drug Interactions
One of the challenges facing physicians prescribing antidepressants to patients who also use cannabis (or any other substance, for that matter) is that it makes it more difficult to prescribe the most appropriate drug at the right dose, and co-occurring cannabis use can impede their ability to accurately assess efficacy of prescribed drugs.
Physicians note that one of the most significant variables when patients combine any sort of drug — over-the-counter, prescription, or illicit — is the ability to measure to what degree each produces side effects and how they affect behavior and mood. Obviously, the more substances a patient is using, the more difficult it is to isolate the effects of each. This is why physicians will often start a patient on one drug and add other drugs later.
Cannabis users who are considering a new prescription drug to treat depression or anxiety may want to consider — at least temporarily — abstaining from use and allowing the antidepressants to take effect. Allan Schwartz, LCSW, Ph.D. a psychotherapist and licensed clinical social worker in Colorado and New York, has found that (particularly in severe cases) patients should abstain from cannabis and other substances during treatment. “I was, at times, able to get patients to agree to stop their marijuana use for a few weeks just so they could determine whether there was or was not an improvement in mood,” says Schwartz. “These individuals were surprised, but were willing to admit that they felt real improvement in mood and functioning.”
There’s also evidence to suggest patients are more likely to misuse cannabis or transition from occasional to chronic use when they’re depressed. In fact, those suffering from anxiety or depression use cannabis at rates between two and eight times greater than those without these conditions.