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A new study shows that CBD may help alleviate short-term anxiety compared to THC, the psychoactive compound in cannabis. J. Anthony/Stocksy
  • Cannabinol, or CBD, may have potent short-term anti-anxiety properties according to a new study.
  • The results show that CBD was more effective at reducing anxiety than THC, the psychoactive compound in cannabis that produces a high.
  • Legal issues make controlled research of CBD difficult, leading to many unresolved questions about the compound found in Cannabis sativa plants.

Cannabis sativa is a complex plant, containing about 750 bioactive compounds.

The most well-known of these is THC, tetrahydrocannabinol, the chemical in cannabis that produces an altered mental state or “high.” The plant also contains cannabidiol or CBD.

Most CBD comes from hemp, a form of cannabis that contains no more than 0.3% of THC, although it may also be derived from cannabis containing more.

A new study finds that CBD-dominant forms of cannabis appear to have significant anti-anxiety properties. The findings add to a growing body of research suggesting the potential mental health benefits of using CBD.

The study is published in the journal Cannabis and Cannabinoid Research.

Anxiety disorders are experienced each year by 40 million Americans over the age of 18. Many studies have looked at using cannabis to help treat anxiety disorders, but robust evidence on efficacy is lacking.

For the study, researchers wanted to compare the effects of CBD versus THC on anxiety symptoms. They examined a sample of 300 people, with 42 people who had never ingested any cannabis and 258 who had occasionally. The non-users with reported symptoms of anxiety served as a control group, with the remaining participants divided into three groups.

One-third smoked a product that was 24% THC, with just 1% CBD. The second group smoked a product with 24% CBD and 1% THC. A third group smoked a cannabis flower with a one-to-one relationship between the two compounds: 12% CBD and 12% THC.

All cannabis users purchased their own product from dispensaries, according to researchers’ requirements. Individuals were not instructed on their frequency of cannabis use. During the 4-week trial period, the researchers traveled to participants’ homes.

To track short-term, acute changes in anxiety immediately after smoking, the researchers employed the Profile of Mood States Elation, Tension, and Paranoia sub-scales and the Addiction Research Center Inventory intoxication scale.

To assess less acute changes to anxiety levels, the Patient Global Impression of Change scale and the Depression, Anxiety, and Stress Scale were used.

At the end of the study period, all four groups reported some reduction in anxiety, although the non-cannabis group showed the least improvement. The THC-dominant group also did not exhibit significant anti-anxiety effects.

The CBD-dominant group showed the most profound improvement. In addition, unlike the other two groups, participants did not experience tension or paranoia, as did members of the other cannabis groups.

Surprisingly, while those in the CBD-dominant group did not feel impaired, they did feel less tense immediately after smoking. They were also less likely to experience paranoia immediately after use than those in the two other cannabis groups.

In reasonable doses, CBD is tolerated by most people and considered safe. However, CBD products are largely unregulated, and the effects of using it for anxiety are not well understood.

CBD products range anywhere from 99% pure CBD to broad-spectrum and full-spectrum offerings, where the cannabinoid percentage may be unclear. CBD product labeling is not always accurate due to the lack of regulation.

‘CBD interacts poorly with some known medications and can cause liver complications, especially at high doses. Folks should discuss use with their physician prior to starting,” first study author Dr. L. Cinnamon Bidwell, PhD, associate professor at the Institute of Cognitive Science at the University of Colorado Boulder told Medical News Today.

Dr. Staci A. Gruber, PhD, director of the Cognitive and Clinical Neuroimaging Core and the Marijuana Investigations for Neuroscientific Discovery (MIND) program at McLean Hospital, not involved in the study, said that research about the effects of CBD is lacking.

“We don’t generally see problems or concern with regard to psychiatric or psychological conditions,” Dr. Gruber told MNT. “Do we have a ton of dose-finding studies on that? We do not — not yet.”

Dr. Natania Crane, PhD, assistant professor in the Department of Psychiatry at the University of Illinois Chicago and the associate director of the UIC Recovery Clinic, not involved in the study, noted there’s insufficient evidence about using CBD for mental health issues.

“THC-dominant cannabis is what many people use, and that is associated with worse mental health over time — we know less about how CBD-dominant cannabis impacts individuals with mental health disorders,” Dr. Crane said.

Dr. Patricia Di Ciano, assistant professor in the Department of Pharmacology and Toxicology at the University of Toronto, also not involved in the study, added that most of what is known about CBD dosing is based on oral preparations such as oils. She told MNT there’s not enough evidence to support the safety of smoked or vaped CBD.

”This is important to address because CBD-dominant cannabis in smoked and vaped forms [is] becoming more widely available with increased consumer access to cannabis. The user should be aware of the harmful chemicals in smoked cannabis, and the risks of vaped CBD are not known.”

— Dr. Patricia Di Ciano, assistant professor of pharmacology and toxicology

Researchers interested in studying the effects of THC or CBD under controlled conditions face an uphill legal battle.

“Under an IND, or investigation of a new drug approval, by the FDA, you can’t evaluate a product currently for sale because you’re assessing it as a [pre-market] drug,” Dr. Gruber explained.

For example, she continued, while a trial subject is free to go out and buy 50 bottles of a commercially available product, researchers can’t legally administer cannabis products to study participants.

“I can’t give you one drop as your study doctor. I can hand it to you as your friend, your neighbor. I can’t give you any as your study doctor,” Dr. Gruber said. “So we all try very hard to come up with models to assess real-world scenarios.”

Dr. Di Ciano said that not many large-scale clinical trials have investigated the efficacy of CBD for treating anxiety. “We need science to help us understand the way CBD works and its potential for treating mental illnesses,” she said.

Dr. Gruber noted the new research may be one of the first studies to examine the effects of different inhaled products using a real-world versus lab-based approach.

“When you are able to use real-world products in studies, you have a much more ecologically valid set of results,” she noted.

Dr. Di Ciano said the amount of time CBD remains in the body is unclear.

She explained that regular users of THC and CBD respond differently than other users. She also noted the importance of dose size since larger doses take longer to leave the body.

“The route of administration is really critical. We know that the effects of oral THC are more prolonged than smoked or vaped THC. The effects of oral THC can last for many hours,” Dr. Di Ciano explained.

“This is another reason why clinical trials are very important to understand the best dose, frequency, and route of administration of THC and CBD in treating anxiety,” Dr. Di Ciano said.

Dr. Bidwell noted, however, that their study data “suggests that CBD-dominant flower was associated with short-term tension reduction for 1–2 hours after use.”

Experts say several factors suggest that it’s too soon to recommend CBD for anxiety.

“I think that CBD is fairly misunderstood. People think that all products are created equally, and they’re not,” Dr. Gruber said.

Dr. Di Ciano noted there’s a “perception that CBD can help with a number of illnesses, but the scientific evidence does not support that at this time.”

“It would be preferable if cannabis-based treatments are sought under medical supervision,” Dr. Di Ciano said.

For now, a conservative approach to using cannabis for anxiety may be best.

“If a number of clinical trials show that CBD is effective and safe in the long term for treating anxiety in a wide variety of populations, only then should it be made widely available as a medication under medical supervision,” Dr. Ciano concluded.