An illicit drug is one used for an illegal purpose. The use of a particular substance may be illicit in some circumstances but legal in others. Taking a controlled substance prescribed by a doctor for a diagnosed medical problem would not be illicit, but taking the same substance without a prescription to experience the effects would be.
The illicit use of drugs can result in addiction. This occurs when the person taking the drug continues using it despite detrimental effects on one’s life. According to CNN, the addictiveness of a particular substance depends on a complex set of factors, including the ease of getting hooked and the severity of withdrawal symptoms when an addicted person stops taking it. A study has identified three of the most addictive illicit drugs.
According to the DEA, barbiturates are depressants that work on the central nervous system. Since the 1900s, doctors have prescribed them to treat anxiety and insomnia. However, with the development of more effective medications to treat these conditions, barbiturates are no longer as widely available by prescription as they once were. Much of the barbiturate use that continues today is illicit.
Cocaine is a Schedule II substance, meaning that it has federal approval for very specific medical uses. However, because it is so dangerous, doctors rarely prescribe cocaine. Its use is almost always illicit. Cocaine is a stimulant that speeds up metabolism and increases alertness, often accompanied by a rush of euphoria. It can also put a strain on the cardiovascular system, which can cause serious complications such as stroke or cardiac arrest.
Heroin is a Schedule I controlled substance, meaning that it has no accepted medical uses. It is a potent narcotic that induces drowsiness after an initial rush of euphoria. It can slow down breathing to dangerously low levels.
Not all addictive substances are illicit. Alcohol and tobacco are also among the top five most addictive substances in the world, but their use is legal by adults.