For any drug to have an effect requires five steps: absorption, distribution, action, metabolism, and excretion. Adolescents use drugs for many reasons, not all of which relate to anticipated psychoactive effects. These may include the expression of opposition to adult authority, peer group identification, the attempt to establish a particular image, developmental emergence into a more mature status, or as a way to cope with problems. Many drugs produce euphoria or elation; others may produce hallucinations, confusion, and loss of inhibitions. Others, like opiates and barbiturates, alleviate anxiety. Once an adolescent uses drugs to produce good feelings, psychological or emotional dependence may follow. The use of drugs to achieve normal function is characteristic of compulsive users. The effects of drugs varies by individual and by drug, but all have physical and mental consequences. Common drugs of abuse include alcohol, marijuana, sedatives and tranquilizers, amphetamines, inhalants, cocaine, hallucinogens, and heroin. The consequences of drug use are compounded for individuals who use more than one substance. 14 references.