Stimulant abuse can include a broad category of substances from amphetamines to caffeine that are taken to increase mental activity, offset drowsiness and fatigue, improve athletic performance, curb appetite, and reduce symptoms of depression. Amphetamines and their derivatives are chemically produced central nervous system (CNS) stimulants that are also commonly used for the treatment of ADHD. Other forms of stimulants include cocaine, crack (a chemically produced form of cocaine), and crystal meth or “ice,” as well as legal substances such as caffeine and nicotine (for persons 18 and older). Of recent concern is the increase among adolescents abusing Ritalin (street named Vitamin R, R-ball, or smart drug). Stimulants can be ingested in tablet or liquid form, smoked, inhaled (snorted), or injected into the blood stream.