Stimulants are used therapeutically to increase alertness or as recreational drugs. They can be also used as appetite suppressants and for boosting productivity. Talk about caffeine, amphetamines, cocaine, Crack Cocaine, Benzedrine, Benzphetamine, Butyl Nitrite, Dextroamphetamine, Methamphetamine, Methylphenidate, Phenmetrazine, etc). Hallucinogens are drugs that alter perceptions, thoughts and feelings. Talk about LSD, mescaline, MDMA (ecstasy), PCP, and psilocybin (magic mushrooms).