Cannabis has a long history as a medication that can be utilized for psychiatric disorders. Over 1000 years before Christ, the Indians had utilized cannabis as a hypnotic and tranquillizer in the treatment of anxiety, mania, and hysteria. The Assyrians described cannabis as an anti-depressant and would utilize the plant to relieve symptoms of depression. During the 20th century, cannabis extracts were beginning to be developed by the medical community for the use of various conditions including mental health disorders. During this time, cannabis was found to be an effective treatment option as a sedative and hypnotic for the treatment of mental health conditions such as insomnia and mania. Eventually by the 1930s, the use of cannabis in mental health treatment had begun to decline for a few reasons: cannabis was not well understood as a pharmaceutical agent because research was in its infancy and none of the chemical constituents of the plant had been isolated; the medical cannabis extracts being produced at the time had a varied composition and potency, producing inconsistent effects; new pharmacological agents had been developed for the treatment of various conditions, including psychiatric disorders, that had clinical research to support their use; and cannabis became an illegal substance.
Cannabis users can experience mood changes; these changes are attributed to the fact that one of the cannabinoid receptors (CB1 receptors) are heavily concentrated in areas of the brain involved in fear, stress, emotions and rewards such as the amygdala, nucleus accubens, hippocampus and prefrontal cortex. Research on cannabis and anxieties often provide conflicting results on its therapeutic benefits. This is best exemplified through the subjective experiences of cannabis users and the documented adverse effects of the drug; the most common reason expressed for using cannabis by chronic users is to promote relaxation and reduce tension, however, one of the most consistently documented adverse effects of cannabis intoxication is the appearance of anxiety and panic-like symptoms.
Research has shown that non-habitual users of cannabis can experience acute or short-lasting episodes of anxiety that often resemble panic attacks. Additionally, high doses of cannabis have also been linked to acute episodes of anxiety. Novice and naive cannabis users are more likely to experience acute anxiety episodes when utilizing cannabis and this has been directly linked to an aversion (avoidance) of further cannabis use. Cannabis has also been shown to further exacerbate existing anxiety symptoms and even counteracts the effects of certain anxiolytic (anti-anxiety) medications.
It has also been found that chronic cannabis users tend to have increased levels of anxiety when compared to non-users. A study with individuals that had been using cannabis on a regular basis over 10 years, found that about 20% of these chronic cannabis users have high levels of anxiety. Chronic cannabis use has also been linked to comorbidity with anxiety disorders. Comorbidity or concurrent disorder is the presence of one or more additional disorder/disease that occurs simultaneously with a primary disease or disorder. This is often the case with patients that have substance abuse disorders, as they will usually present with another mental health illness (for instance, a patient with alcohol dependency may also suffer from depression). Patients that suffer from cannabis dependence or abuse will often also have an underlying concurrent mood disorder such as anxieties. Furthermore, cannabis dependence has also been linked to an increased risk of developing panic attacks or panic disorders. Anxieties are also one of the manifestations of cannabis withdrawal.
Delta-9-tetrahydrocannabinol or THC has been the main cannabinoid that is often associated with the anxiety causing symptoms of cannabis. Cannabinoids are the main chemical compounds responsible for producing the effects associated with cannabis. Research has shown that cannabis’ anxiogenic (anxiety-producing) effects are often the product of THC and high cannabis dosages. Furthermore, the anxiogenic effects produced by cannabis can often produce an increased aversion to the drug, especially among new users. Although THC is often attributed with the anxiogenic effects of cannabis, cannabidiol or CBD has demonstrated through research of possessing anxiolytic (anti-anxiety) properties.
CBD has been shown to have anxiolytic properties while being linked to a weakening of the effects of THC. Research is beginning to explore the benefits of CBD in treating anxiety disorders. For instance, one study conducted a stimulated public speaking test while utilizing CBD on a group of participants to examine its effects on social anxiety; CBD was provided in 300 mg dosages and participants in the study that had used the CBD prior to the stimulated public speaking test showed a reduction in their anxieties. The results from the test with CBD were then compared to results produced by a placebo and two other anxiolytic substances (diazepam and ipsapirone). The study concluded that CBD and the other two anxiolytic substances reduced the social anxieties produced by the stimulated public speaking test.
Another study examining CBD’s anxiolytic effect employed single-photon emission computed tomography to monitor the participant’s brain activity while providing them 400 mg of CBD and a placebo. Single-photon emission computed tomography or SPECT, is an imaging tool that uses nuclear medicine and gamma rays to provide a true 3D image. For this study patients were injected with radioactive tracer technetium-99 (which is required for the SPECT scan) through catheters in their arms. The aim of the testing was to induce anxiogenic effects, which it did, in order to allow researcher to examine if CBD would counteract these effects. The SPECT imaging showed an increase in activity in the left amygdale-hippocampus complex extending to the hypothalamus and left posterior cingulated cortex. This pattern of brain activity is consistent with findings of anti-anxiety effects and further demonstrated CBD’s anxiolytic capabilities.
Furthemore, cannabis’ anxiogenic effects may be dose-dependent. Research tends to indicate that higher doses of cannabis tends to produce anxiogenic effects where as lower doses have been shown to promote anxiolytic effects. For instance, the pharmaceutical cannabinoid, nabilone (low dose synthetic THC analogue), has been shown to demonstrate anxiolytic effects in lab animals. It has also been shown that inhibition of the endocannabinoid signaling processes as well as over-stimulation of the endocannabinoid system has been linked to anxiety-like effects; whereas, moderate endocannabinoid stimulation has been shown to decrease stress and anxiety. As mentioned previously, often cannabis strains higher in the psychoactive compound THC will demonstrate anxiogenic properties.
In conclusion, there is definitely a need to conduct more research in order to fully understand cannabis’ relationship with anxieties. Current research regarding cannabis and anxieties is conflicting as there is some documented research and anecdotal evidence to support cannabis’ potential as a therapeutic agent for anxiety; however, research also points to its ability to induce and worsen anxiety like symptoms, especially among heavy, chronic cannabis users. The evidence today highlights that patients wanting to use cannabis for anxieties should utilize a low dose of cannabis or strains with higher CBD content.