A central nervous system stimulantThese are drugs that act on the central nervous system, and increase alertness. They are commonly used to treat learning disabilities. Also, some of the most commonly abused drugs fall into this category, including amphetamines, methylphenidates, and dextroamphetamines. More used as a recreational drugA name for a wide variety of chemical substances capable of altering the function of your mind and body in significant ways. These can include over the counter prescriptions, alcohol, and controlled substances. Most drugs are either physically and/or psychologically habit-forming. More. Commonly known as meth, it is one of the most popular and destructive drugs in the United States. Its consumption and production involve major health and societal risks.