The effects of drug abuse and dependence vary, depending on the type of drug, polydrug use, and characteristics of the user. The influence of genetic, neurochemical, neuropsyiological, sociocultural, and economic factors suggest that the etiology of substance abuse and dependence is multiply determined. Models explaining the causation of substance abuse have arisen and various classification systems for drugs, their effects, and the behavior of persons abusing drugs have been developed. This paper presents an overview of the characteristics of drugs commonly abused and their effects. Drugs discussed are: alcohol, inhalants, marijuana, LSD and other hallucinogens, caffeine, amphetamines and other stimulants, tobacco, barbiturates and non-barbiturate sedatives, opiates, cocaine, prescription drugs, and over-the-counter medications. Information provided about drugs and about aspects of substance abuse provides counselors with perspectives they can use to increase the effectiveness of their communications with clients and with others who work with or care about consumers and their families. Also included is a facilitator's manual which is a practical guide for teaching content through guided experiential projects. Six objectives are listed. Five student exercises are provided. (MKA)