Delta-9-Tetrahydrocannabinol: What to Know About THC

THC stands for delta-9-tetrahydrocannabinol or Δ-9-tetrahydrocannabinol (Δ-9-THC). It is a cannabinoid molecule in marijuana (cannabis) that's long been recognized as the main psychoactive ingredient—that is, the substance that causes people who use marijuana to feel high.

THC is just one of more than 500 different substances—and 100 different cannabinoid molecules—in marijuana. Although THC is the most recognized, another important cannabinoid molecule that has received major interest is cannabidiol (CBD).

Marijuana can be addictive, so it is important to be aware of the effects and risks of THC. This article discusses what you need to know about the effects of THC, it's potential medicinal uses, and the risks of substances that contain THC.

History of THC

Cannabis has a long history of use that dates back thousands of years. The first recorded use of cannabis has been traced to China, where it was used for food, textiles, and medicine. Hemp was eventually introduced to Europe and later to the Americas, where it was used for both recreational and ritual purposes. 

Cannabis was introduced to what is now the United States during the 1600s. Hemp was grown to produce textiles and sometimes even used as legal tender. It was used for a number of medical purposes as well, with its recreational use beginning to grow during the 1930s and 1940s.

Around this time, anti-drug campaigns were instituted against its use and many states passed laws prohibiting marijuana. The 1936 film "Reefer Madness" portrayed marijuana as a dangerous drug that led to psychosis, violence, and suicide. 

In 1970, the Controlled Substances Act classified marijuana as a Schedule I drug, identifying it as having a high potential for abuse and making the drug illegal at the federal level. The "war on drugs" launched during the 1970s led to the large-scale incarceration of many people for marijuana possession and use.

Statistics suggest that the enforcement and penalization of marijuana laws disproportionately target people of color. While drug use has similar rates for people of all racial and ethnic backgrounds, Black and Latinx people are far more likely to be arrested and jailed for drug offenses.

Effects of THC

THC works by attaching to the body's cannabinoid receptors, which are found throughout the brain and nervous system. THC also activates the brain's reward system. This triggers the release of dopamine, a neurotransmitter that causes pleasurable effects. 

Because of this reward system activation, the brain learns to repeat the rewarding behaviors that lead to pleasant feelings. This is what contributes to the addictive properties of THC. Using higher amounts of THC for longer periods of time increases this risk for addiction.

Forms of THC

THC is available in a variety of forms. The method of administration often depends on why THC is being used and what it is intended to treat. Some of the ways it can be consumed include by:

• Inhalation: This is the fastest method of administration and produces effects within minutes. Recent reports suggest that vaping THC oil may pose serious and potentially fatal safety risks. The CDC and FDA both recommend avoiding all vaping an e-cigarette produces, particularly those that use THC oil.
• Oral ingestion: THC can be taken by mouth in the form of capsules, edibles, tinctures, or oils. This method of delivery produces slower, longer-lasting effects.
• Topical application: THC can also be included in lotions, balms, salves, oils, and bath salts that are then applied to the skin. The effects of this method are usually localized, which means that they are unlikely to have psychoactive effects. However, such products may be helpful in reducing pain and inflammation.
• Sublingual administration: THC can also be consumed as lozenges, sprays, or dissolvable strips that are placed under the tongue and dissolved.

THC in CBD Products

With the popularity of CBD, there has been a major market shift toward producing a seemingly endless variety of CBD products. Some of these products may contain traces of THC (around 0.3% to 0.9%), depending on how they're formulated.

This small concentration is highly unlikely to produce psychoactive effects, and some experts argue that the effectiveness of CBD is potentiated by small amounts of THC, a phenomenon known as the "entourage effect."

However, if you're looking for a CBD product without any THC, be sure to select one that uses third-party testing to certify the purity of the product.

Uses for THC

THC has a number of medicinal uses. Marijuana has been used for medicinal purposes for thousands of years, although scientific research on its use to alleviate and treat illness is still relatively recent.

According to the National Center for Complementary and Integrative Health, a division of the National Institutes of Health, some of the mental health conditions that THC may help include:

• Anxiety 
• Depression
• Insomnia
• Migraines
• Opioid use disorder
• Post-traumatic stress disorder (PTSD)
  

However, the FDA has approved the synthetic THC medication dronabinol (sold under the brand names Marinol and Syndros) and a drug containing a synthetic substance similar to TCH known as nabilone (brand name Cesamet). Dronabinol is used to treat vomiting and nausea caused by chemotherapy and low appetite and weight loss caused by HIV/AIDS. Nabilone is also used to treat nausea and vomiting.

Potential Pitfalls of THC

There is considerable research-based evidence that THC is associated with an increased risk of psychosis, both among adolescents and adults. It is also linked to increased anxiety, learning impairment, and decreased memory formation.

CBD has been found to help counter these effects, reducing anxiety, improving learning ability, and working as an antipsychotic—although much of the available research is on animals. When taken together, as is the case with marijuana use, CBD seems to reduce the negative effects of THC.

A 2013 meta-analysis, which is a type of study that looks at the results of many previous studies, also found some evidence that THC may be neurotoxic as there are differences in the brain structure of people who regularly use marijuana (and who do not have psychosis).

One interesting point underscoring brain changes: While research has shown a reduction in gray matter volume in the prefrontal cortex of people with a history of heavy marijuana use, there is an apparent compensatory response. The density of fibrous connections among remaining neurons increases, which may cancel out some or all of the neurotoxicity. 

Is Delta-9 THC Addictive?

Cannabis is the most commonly used federally illegal substance in the United States. Despite the common belief that the drug is not addictive, THC tolerance and dependence (precursors to addiction) have been widely documented.

Similar to other types of addiction, cannabis use disorder involves a preoccupation with the drug, bingeing, and symptoms of withdrawal when it cannot be used. Additional criteria for diagnosing an addiction include experiencing constant cravings and having drug-related relationship and social issues.

Amount of THC in Marijuana

Americans are definitely not dealing with the same THC products as in the past. This is because today's marijuana is much more potent, with THC concentration levels increasing from 9.75% in 2009 to 13.88% in 2019.

For comparison purposes, the THC content of marijuana back in the 1960s, 1970s, and 1980s was under 2%, increasing to around 4% in the 1990s. Additionally, some strains today have an even higher content, including some that contain as much as 28% THC.

The amount of THC contained in marijuana varies by the way that the cannabis is prepared for use. THC levels may exceed 50% in products made from marijuana extracts. These higher THC levels increase the risk of developing a marijuana addiction.

How to Get Help

If you or a loved one wants to stop using THC but are finding this difficult, several options exist. Treatments for cannabis use disorder that show promise for providing positive results include:

• Cognitive behavioral therapy, which helps people identify and correct behaviors associated with drug use
• Contingency management, a treatment approach that involves receiving rewards when a desired behavior occurs (or does not occur)
• Motivational enhancement therapy, which promotes an internal desire for change and motivation to engage in treatment

While some suggest that drugs such as selective serotonin reuptake inhibitors (SSRIs) and anxiolytics (anti-anxiety medications) may help treat cannabis use disorder, evidence is lacking due to small study sizes and varying methods of assessing treatment outcomes.