Illicit drug use

Refers to the use and misuse of illegal and controlled drugs. (Also see Sources and Definitions, Substance use.)

Monitoring the Future (MTF)

In this school-based survey of secondary school students, information on illicit drug use is collected using self-completed questionnaires. The information is based on the following question: “On how many occasions (if any) have you used [substance] in the last 30 days?” Similar questions are asked about lifetime and past-year use of marijuana and a range of other drugs, including hallucinogens, inhalants, cocaine, and heroin.

In 2017, questions on vaping were revised to include separate questions about vaping nicotine, marijuana, and just flavoring. Students are first asked the screener question: “To ‘vape’ is to use a device such as a JUUL, vape-pen, e-cigarette, e-hookah, or e-vaporizer to inhale a vapor into the lungs. Have you ever vaped?” Students who reply “yes” are then asked additional questions about specific substances they have vaped over different time frames. They are asked about marijuana with the question: “On how many occasions (if any) have you vaped marijuana in the last 30 days?” They are also asked about vaping nicotine and vaping just flavoring in the same format.

Questions on cocaine use include the following: “On how many occasions (if any) have you taken crack (cocaine in chunk or rock form) during the last 30 days?” and “On how many occasions (if any) have you taken cocaine in any other form during the last 30 days?” Starting in 2014, the question on MDMA asks, “On how many occasions (if any) have you taken MDMA (ecstasy or Molly) during the last 30 days?” Previously, the question only asked about ecstasy use before Molly—a nickname for a supposedly stronger form of MDMA—became a popular form of the drug.

National Survey on Drug Use and Health (NSDUH) (last updated June 2023)

Information on illicit drug use is collected for survey participants age 12 and older. Information on any illicit drug use includes any use of marijuana or hashish, cocaine, crack, heroin, hallucinogens, inhalants, or methamphetamine, as well as misuse of prescription psychotherapeutic drugs. Prescription psychotherapeutics include pain relievers, tranquilizers, stimulants, and sedatives; over-the-counter drugs are excluded. Misuse of prescription psychotherapeutics is defined as use in any way other than directed by a healthcare provider. Such misuse may include obtaining the drug without a valid prescription or using the prescribed drug in greater amounts, more often, longer than told, or in any other way not directed by a doctor. Current use (within the past 30 days) is based on the question: “How long has it been since you last used [drug name]?” This answer is cross-checked with the following question: “Think specifically about the past 30 days, from [DATE] up to and including today. During the past 30 days, on how many days did you use [drug name]?” Starting in 2013, information about marijuana use that was recommended by a doctor or other healthcare professional has been collected; however, reported marijuana use is classified as illicit drug use. Starting in 2015, the NSDUH questionnaire was partially redesigned, and changes in measurement for 7 of the 10 illicit drug categories—hallucinogens, inhalants, methamphetamine, misuse of prescription pain relievers, tranquilizers, stimulants, and sedatives—may have affected comparability of the measurement of these illicit drugs and any illicit drug with earlier years.