SUBSTANCE RELATED DISORDERS
The two disorders in this category refer to either the abuse or dependence on a substance. A substance can be anything that is ingested in order to produce a high, alter one's senses, or otherwise affect functioning. The most common substance thought of in this category is alcohol although other drugs, such as cocaine, marijuana, heroin, ecstasy, special-K, and crack, are also included. Probably the most abused substances, caffeine and nicotine, are also included although rarely thought of in this manner by the layman.