Juvenile substance abuse prevention involves having facts about different drugs and their effects, having firm values regarding drugs and alcohol, understanding the emotional needs of young people, developing good communication skills, and talking about drug and alcohol abuse at schools and in families. The availability, use, and effects of psychoactive drugs, including alcohol and other depressants, marijuana, stimulants, hallucinogens, inhalants, and prescription drugs are briefly described. Some early warning signs of juvenile drug use include underachievement, changes in friends, changes in behavior, withdrawal from family and friends, dramatic breaking of rules at home and at school, and missing money or items of value.