A designer drug is a chemical substance that duplicates the pharmacological effects of a controlled substance. Designer drugs are often made by manipulating the formulas of the chemicals that are used to create a particular controlled substance. Historically most designer drugs have been opioids, hallucinogens and anabolic steroids (e.g., Ecstasy and Ketamine). By the mid-1980's, most of the existing designer drugs had been added to the DEA's Controlled Substances list. In 1986, the Controlled Substance Analogue Enforcement Act went into effect, which was designed to ban designer drugs before they could be made by making it illegal to possess, sell or manufacture chemicals that are substantially similar in pharmacology or chemistry to Schedule I or Schedule II drugs.