What Is THC?

Medical Marijuana
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What Is 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 400 different active substances—and 60 different cannabinoid molecules—contained in marijuana, although THC is the most recognized. Another important cannabinoid molecule that has received major interest is cannabidiol (CBD).

How THC Works

THC works by attaching to the body's cannabinoid receptors, which are found throughout the brain and nervous system. THC can be detected in the body much longer than most other drug compounds (up to 20 hours after ingestion), although the psychoactive effects only last for a few hours.

THC is also stored in body fat and organs for three to four weeks. Hair follicle testing may identify THC after even longer periods of time, around 90 days. Urine testing is often used but has been found to be an unreliable method of detection.

Forms of THC

THC is often smoked as marijuana (dried leaves of the Cannabis plant), but there are actually a number of different ways that THC can be used. It can be consumed by:

  • Inhalation: This is the fastest method of delivery and produces the quickest psychoactive effects, with people beginning to feel effects within minutes. There are a couple of different ways that THC can be inhaled. It may be smoked or vaped, although recent reports suggest that vaping may pose safety risks that need further investigation.
  • Oral Ingestion: THC can be taken by mouth in the form of capsules, edibles, tinctures, or oils. While this method of delivery takes longer to have an effect, the effects tend to last longer.
  • 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 of application are usually localized, which means they are unlikely to have psychoactive effects. However, such products may be helpful for reducing pain and inflammation.
  • Sublingual administration: THC can also be consumed as lozenges, sprays, or dissolvable strips that are placed under the tongue.

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 result in a feeling of high, and some experts argue that the effectiveness of CBD is potentiated by small amounts of THC. However, if you're looking for a CBD product without any THC, be sure to seek out a source that uses third-party testing to certify the purity of the product.

Uses

THC is used recreationally, but it also has a number of medicinal uses as well. Marijuana has been used for medicinal purposes for thousands of years, but research on its use to alleviate and treat illness is still relatively recent.

Some of the ailments that THC may help include:

  • Anxiety 
  • Depression
  • Glaucoma
  • Inflammation
  • Inflammatory bowel disease (IBD)
  • Insomnia
  • Irritable bowel syndrome
  • Migraines
  • Multiple sclerosis
  • Muscle spasticity
  • Nausea
  • Pain
  • Poor appetite
  • Post-traumatic stress disorder (PTSD)
  • Reducing opioid use
  • Seizures
  • Symptoms associated with HIV/AIDS

The FDA has also 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 used to also used to treat nausea and vomiting.

Impact

THC stimulates the release of a neurotransmitter called dopamine in the brain, which is what causes feelings of euphoria. The effects on the body can vary from one person to the next.

People may also experience:

  • Altered perception of time
  • Feelings of relaxation
  • Heightened sensory perception
  • Increased appetite

While it can cause pleasant effects, TCH can also lead to adverse reactions as well. People can experience anxiety, memory problems, hallucinations, or delusions in some cases.

Potential Pitfalls

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

CBD, on the other hand, has been found to counter those effects, reducing anxiety, improving learning ability, and working as an antipsychotic, although much of the 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 combines the results of many previous studies, found some evidence that THC may be neurotoxic. There are differences in the brain structure of people who regularly use marijuana who do not have psychosis.

One interesting point underscoring the brain changes: While there is a reduction in gray matter volume in the prefrontal cortex in chronic users, there is an apparent compensatory response. There is a subsequent increase in the density of fibrous connections among remaining neurons, which may cancel out some or all of the neurotoxicity. 

Research into the effects of THC (or delta-9-THC) is complicated by many factors, but there is sufficient evidence that THC can be harmful, particularly to younger people whose brains are still developing. They should, therefore, avoid frequent use of marijuana.

Is Delta-9 THC Addictive?

Cannabis is the most common substance misused in the United States, after alcohol and tobacco. Despite the belief by many that the drug is not addictive, THC tolerance and dependence have been widely documented in various studies.

According to the NIDA, about 30% of people who use marijuana will become addicted—and using the drug prior to age 18, when the brain is still developing, increases the likelihood of a marijuana use disorder four- to seven-fold. Similar to other types of addiction, marijuana use disorder involves a preoccupation with the drug, bingeing, and symptoms of withdrawal when you can't use the drug.

Amount of THC in Marijuana

We're definitely not dealing with the same pot as we were in the past. This is because today's marijuana is much more potent, with THC levels averaging 9.6%, according to the National Institute on Drug Abuse (NIDA). By comparison, in the early 1990s, marijuana generally had a THC level of about 4%.

The strength of modern "high-potency" strains of marijuana, such as sinsemilla ("skunk"), was reportedly at least four times as strong, containing about 15% THC. The amount of THC contained in marijuana varies by the way that cannabis is prepared for use, such as leaf/bud, hashish, or hashish oil. THC levels can exceed 50% in products made from marijuana extracts.

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 came to use for both recreational and ritual purposes. 

Cannabis was first introduced in the U.S. during the 1600s. Hemp was grown to produce textiles and was sometimes even used as legal tender. It was used for a number of medical purposes as well, but its recreational use began to grow during the 1930s and 1940s.

Around this time, anti-drug campaigns began 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.

While it is still not legal at the federal level, many states have approved the use of cannabis and THC for medical and, in some states, recreational purposes. You should always check state laws where you live before purchasing any products containing THC.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

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