18.n. Substance dependence; or failed a drug test ever; or substance abuse or use of illegal substance in the last 2 years. "Substance" includes alcohol and other drugs (e.g., PCP, sedatives and hypnotics, anxiolytics, marijuana, cocaine, opioids, amphetamines, hallucinogens, and other psychoactive drugs or chemicals). For a "yes" answer to Item 18.n., the AME should obtain a detailed description of the history. A history of substance dependence or abuse is disqualifying. The AME must defer issuance of a certificate if there is doubt concerning an applicant's substance use. (See Item 47 Psychiatric)