When used as drugs of abuse and not under a doctor’s supervision, stimulants are frequently taken to: produce a sense of exhilaration, enhance self esteem, improve mental and physical performance, increase activity, reduce appetite, extend wakefulness for prolonged period, and “get high.” Chronic, high-dose use is frequently associated with agitation, hostility, panic, aggression, and suicidal or homicidal tendencies. Paranoia, sometimes accompanied by both auditory and visual hallucinations, may also occur. Tolerance, in which more and more drug is needed to produce the usual effects, can develop rapidly, and psychological dependence occurs. In fact, the strongest psychological dependence observed occurs with the more potent stimulants, such as amphetamine, methylphenidate, methamphetamine, cocaine and methcathinone. Abrupt cessation is commonly followed by depression, anxiety, drug craving, and extreme fatigue, known as a “crash.”