Marijuana and Anxiety
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Marijuana and Anxiety

Scientific studies are beginning to paint a clear picture of why many claim chronic use of marijuana can lead to prolonged anxiety—while others insist the drug eliminates it.

Does marijuana cause anxiety? Does it cure it? The dearth of knowledge on THC, caused by prohibitions on research, has made these tricky questions to answer. But scientific studies are beginning to paint a clear picture of why many claim chronic use of marijuana can lead to prolonged anxiety—while others insist the drug eliminates it.

The link between pot and panic is more than anecdotal. Researchers quantified the stress response of individuals taking different doses of cannabis before a mock interview. Their results: those using a low dose of THC seemed less stressed out than the control group, but those using enough of the plant to feel “high” were considerably more anxious.

THC and Fight-or-Flight

So what’s actually happening? THC works by binding to cannabinoid receptors throughout the brain. Recent neuroscience has pinpointed a wealth of cannabinoid receptors in the amygdala, and THC targets those same receptors. When this happens it creates “signals” provoking an emotional reaction. It just so happens the amygdala is the area of the brain that controls our fight-or-flight response. It’s thought to be an emotional hub, capable of inciting both fear and fearlessness.

It’s no surprise that someone who walks into an interview high might end up freaking out. Multiple studies have shown marijuana to slow response time, and indeed participants taking the higher dose had more long pauses during their interviews. These missteps could have keyed a “flight” response, amplified by the wealth of THC binding with receptors in the amygdala. This explains why misuse of cannabis can quickly escalate into full-blown panic and paranoia. This is especially true for new users on a high dose: uncertainty over what is happening to them combined with rapid activity in the brain’s fight-or-flight center may be provoking a supercharged “flight” response.

The anxiolytic effect observed at low doses is interesting, especially because it occurs at a dosage where participants didn’t feel “high.”  Even without a pronounced psychoactive effect, THC is still replicating the effects of our own endocannabinoid signalers deep inside the brain. The same cannabinoid receptors that might trigger a flight response when things seem to be going wrong instead provide a buffer against fear once your instincts determine you’re in a situation you can handle, nudging you towards success.

Chronic Use

Before you commit to microdosing marijuana to banish anxiety forever, though, keep this in mind. Daily doping causes your brain to downregulate its cannabinoid receptors. Think of these receptors like friends and THC like an invitation to a party. Send out an invite once a month, and you can expect a full house. But try and invite your friends over daily, and less and less will show up over time. If you use THC daily to try and goad your cannabinoid receptors into giving you a fear-buffering response, the results will steadily decline. The good news, though, is that receptor activity returns to normal after a period of abstinence.

The downregulation of cannabinoid receptors seen in chronic users may affect anxiety as much or more than the active presence of THC. Eye-tracking tests revealed that chronic users, when not under the active effects of THC, responded to stress-inducing stimuli in a similar manner as those with anxiety disorders: they avoided them. This could mean the downregulation of cannabinoid receptors leaves the mind less equipped to respond to anxiety-inducing situations, causing it to avoid these situations where possible. But it may simply mean that those who use marijuana daily are the same set of people who avoid anxiety-inducing stimuli in the first place.

Of course, if cannabinoid receptors in the amygdala are less active, wouldn’t that result in a muted anxiety response as well?  Such an effect has been observed downstream of brain activity in the body’s release of cortisol. Cortisol, widely known as the “stress hormone,” is the uncomfortable conductor that kicks you into high gear an hour before that project deadline or right after you realize you left your presentation at home. Researchers used a supposedly well-established method of inducing stress: they had participants submerge a hand in ice water and count backwards in intervals of 17, berating them for any errors in arithmetic. Unsurprisingly, cortisol levels in the control group skyrocketed. But chronic cannabis users showed no difference in cortisol levels during the test and when completing ordinary tasks.

The researchers in this study said it was unclear if the subdued stress response left chronic users more or less vulnerable to anxiety in the long term. On the one hand, a reduction in cortisol correlates with reduced discomfort. But the finding could also be interpreted as consistent with the eye-tracking study in showing that chronic users avoid mobilizing resources to handle stressful situations.

What about Cannabidiol?

Walk into a shop selling cannabidiol oil, widely known as CBD, and someone is bound to tell you about its anti-anxiety effects. Research on CBD is even more limited than THC, but there are already many studies on its use in treating panic and anxiety. These studies showed CBD to mediate the effects of anxiety that can be caused by high doses of THC, as well as experiment-induced fear. While CBD does bind to cannabinoid receptors, it’s thought that the anxiolytic effects may be more a result of interaction with the serotonin 1A receptor, the same receptor targeted by anti-anxiety medications like Buspirone.

What isn’t known, however, is what the long-term effects of using CBD are. Does the body adapt by desensitizing its serotonin 1A receptors?  Studies of other serotonin 1A agonists found that use of some treatments, but not all, lead to desensitization after chronic use. It’s not clear at this time whether or not CBD continues to be effective at mitigating anxiety in daily use.

Conclusion

Tracing the interplay between marijuana and the mind is no easy task. We still need more research, and more cooperation from governments that have been slow to ease restrictions on study. But our collective understanding of cannabis’ anxiolytic and anxiogenic effects continues to grow. Here’s what we know now: THC’s psychoactive effects are capable of both clearing and creating anxiety. You can increase your odds of the former by educating yourself on the drug’s effects, and using a moderate dosage in a comfortable setting. Chronic use of marijuana leads to a reduction in the body’s deployment of stress hormones, but likely also robs you of crucial resources needed to handle stressful situations by downregulating cortisol and cannabinoid receptors. CBD, on the other hand, has shown promise in reducing anxiety using a similar mechanism to drugs already approved for treating anxiety disorders. However, its efficacy in the long-term is unclear. As always, approach cannabis use with care and caution, and arm yourself knowledge to help ensure your highs are happy, not harrowing.

James Craven is a senior fellow at Reason Foundation, where he focuses on criminal justice and drug policy issues.