Crystal meth was first seen in South Korea and Taiwan, and came onto the market as a legal appetite suppressant. It is still available in a prescription form to temporarily address obesity, although it's infrequently used for this purpose. The methamphetamine available on the street, however, is most often culled from underground labs, where the drug is cooked up in varying potencies and with differing purity. It usually appears as a white powder, or, in the case of ice, as whitish crystals. As with other stimulants, crystal meth decreases appetite, reduces fatigue, boosts alertness and confidence, and, at higher doses, creates feelings of exhilaration and euphoria.
Users are usually talkative, energetic, and have a sense of well-being.
This is part of what makes crystal so potently addictive. Methamphetamines arouse the central nervous system, increasing heart rate and elevating blood pressure and body temperature. Psychologically, meth can cause anxiety and hallucinations. Heavy users have also experienced something called toxic psychosis , a phenomenon in which the person feels panicked and paranoid, and may behave violently toward other people or themselves. They may also get seemingly stuck in repetitive physical movements or speech patterns.