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Media Guide

Most Commonly Used Addictive Drugs

In recent years, Monitoring the Future, the NIDA-funded annual survey of drug, alcohol, and tobacco use in 8th-, 10th-, and 12th-grade students, has shown persistently high rates of marijuana and nonmedical prescription drug use in our Nation’s teens. More information on the Monitoring the Future survey can be found at www.drugabuse.gov/related-topics/trends-statistics/monitoring-future.


Marijuana (cannabis) is the most commonly used illicit substance. This drug impairs short-term memory and learning, the ability to focus, and coordination. It also increases heart rate, can harm the lungs, and may increase the risk of psychosis in vulnerable people. Research suggests that when regular marijuana use begins in the teen years, addiction is more likely: 1 in 6 users, compared to 1 in 9 among adults. In addition, recent research suggests that heavy cannabis use that starts in the teen years is associated with declines in IQ scores in adulthood. More information on marijuana can be found at www.drugabuse.gov/drugs-abuse/marijuana.

Marijuana Research at NIDA

As part of its mandate to study drug use and addiction and other health effects of both legal and illegal drugs, NIDA funds a wide range of research on marijuana; its main psychoactive ingredient, delta- 9-tetrahydrocannabinol (THC); and chemicals related to THC (cannabinoids such as cannabidiol [CBD]). More information on marijuana research at NIDA can be found at www.drugabuse.gov/drugs-abuse/marijuana/marijuana-research-nida.

Medical Marijuana

Although many have called for the nationwide legalization of marijuana to treat medical conditions, the scientific evidence to date is not sufficient for the marijuana plant to gain U.S. Food and Drug Administration (FDA) approval, for two main reasons.

First, there have not been enough clinical trials showing that marijuana’s benefits outweigh its health risks. The FDA requires carefully conducted studies in large numbers of patients (hundreds to thousands) to accurately assess the benefits and risks of a potential medication.

Second, to be considered a legitimate medicine, a substance must have well-defined and measureable ingredients that are consistent from one unit to the next (such as a pill or injection). This consistency allows doctors to determine the dose and frequency. As the marijuana plant contains hundreds of chemical compounds that may have different effects and that vary from plant to plant, its use as a medicine is difficult to evaluate.

However, THC-based drugs to treat pain and nausea are already FDA approved and prescribed. Scientists continue to investigate the medicinal properties of cannabinoids—or the individual components of the marijuana plant (e.g., THC, CBD). The therapeutic potential lies in developing medications based upon cannabinoids that have therapeutic value but with limited-to-no risk for addiction, such as CBD. For more information, see our “Is Marijuana Medicine?” DrugFacts at www.drugabuse.gov/publications/drugfacts/marijuana-medicine.

Any of the 27 NIH Institutes could fund research in this area. To find out more about NIH-funded research into the therapeutic potential of cannabinoids, contact NIH at mylesr@mail.nih.gov. For more information on research that NIDA is supporting to explore this issue, go to www.drugabuse.gov/drugs-abuse/marijuana/nida-research-therapeutic-benefits-cannabis-cannabinoids.


“K2” or “Spice” refers to a wide variety of herbal mixtures that produce experiences similar to marijuana. Of the illicit drugs most used by high school seniors, Spice is second only to marijuana. It is sometimes called “synthetic” marijuana, but this is a misperception. Labels on Spice products often claim that they contain “natural” psychoactive material taken from a variety of plants; however, chemical analyses show that their active ingredients are synthetic (or designer) cannabinoid compounds.

Poison Control Centers report a variety of K2/Spice symptoms, including rapid heart rate, vomiting, agitation, confusion, hallucinations, raised blood pressure and reduced blood supply to the heart, and, in a few cases, heart attacks. Because the chemicals used in Spice have a high addictive potential and no medical benefit, the Drug Enforcement Administration (DEA) has made it illegal to sell, buy, or possess the main chemicals in these drugs. More information can be found at www.drugabuse.gov/drugs-abuse/k2spice-synthetic-marijuana.

Prescription and Over-the-Counter Medications

Prescription medications and some over-the-counter medications are increasingly being abused (used in ways other than intended or without a prescription). This practice can lead to addiction, and in some cases, overdose. Among the most disturbing aspects of this emerging trend is its prevalence among teenagers and young adults, as well as the common misperception that because these are used medically or prescribed by physicians, they are safe even when not used as intended. Commonly abused classes of prescription drugs include opioid painkillers, stimulants, and depressants.

  • Opioids are usually prescribed for pain relief. Commonly prescribed opioids include hydrocodone (e.g., Vicodin®), oxycodone (e.g., OxyContin®), morphine, fentanyl, and codeine. In the United States, more people now die from opioid painkiller overdoses than from heroin and cocaine combined.
  • Stimulants: Methylphenidate (Ritalin®, Concerta®, Focalin®, and Metadate®) and amphetamines (Adderall®, Dexedrine®) are stimulants commonly prescribed for attention-deficit hyperactivity disorder (ADHD).
  • Depressants are usually prescribed to promote sleep or to reduce anxiety. As measured by national surveys, depressants are often categorized as sedatives or tranquilizers. Sedatives primarily include barbiturates (e.g., phenobarbitol) but also include sleep medications such as Ambien® and Lunesta®. Tranquilizers primarily include benzodiazepines such as Valium® and Xanax®, but also include muscle relaxants and other anti-anxiety medications.
  • “Syrup,” “Purple Drank,” “Sizzurp,” or “Lean” describes soda mixed with prescription-strength cough syrup containing codeine and promethazine—these cough syrups are available by prescription only. Users may also flavor the mixture with hard candies. Drinking this combination has become increasingly popular among some celebrities and youth in several areas of the country. Codeine is an opioid that can produce relaxation and euphoria when consumed in sufficient quantities. Promethazine is an antihistamine that also acts as a sedative. More information can be found at www.drugabuse.gov/drugs-abuse/emerging-trends.

Commonly abused over-the-counter drugs include cold medicines containing dextromethorphan (DMX), a cough suppressant. Products containing DMX can be sold as cough syrups, gel capsules, and pills (that can look like candies). They are frequently abused by young people, who refer to the practice as “robo-tripping” or “skittling.” Pseudoephedrine, a decongestant found in many over-the-counter cold medicines, is another over-the-counter medication that is used illicitly. Although not typically abused in itself, it is one ingredient used to produce methamphetamine. For more information about prescription drug abuse and related health consequences, go to www.drugabuse.gov/drugs-abuse/prescription-drugs-cold-medicines.

This page was last updated October 2016

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NIDA. (2016, October 1). Media Guide. Retrieved from https://www.drugabuse.gov/publications/media-guide

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