Psychoactive drugs are substances that are commonly used today for legitimate medical purposes as well as recreational use among certain individuals. Psychoactive refers to the drugs' effect on brain chemistry. When not being used for medical purposes, people take them because they are often an easy fix for problems such as stress, boredom, or other unpleasant emotional states. They provide immediate gratification for the user and can be pleasurable or entertaining. They are however extremely dangerous, potentially fatal, and many are very addictive. They can cause permanent neurological damage, as well as damage to the central nervous system. There are three main categories of psychoactive drugs: depressants, stimulants, and hallucinogens.
Depressants are psychoactive drugs whose effects are characterized by reduced central nervous system activity, relaxation, numbness, and a pleasurable "buzz". Alcohol, barbiturates, tranquilizers, and opiates all qualify as depressants. Opiates are narcotics, medically prescribed pain killers that are highly addictive.
Minor tranquilizers are also medically prescribed as treatment for anxiety or insomnia. Depressants when abused can be fatal, especially when combined with other depressants.
The effects of stimulants are characterized by an increased rate of autonomic body functions, (heart rate, breathing, etc) and an increase in arousal and alertness; they decrease the desire for sleep. Amphetamines, cocaine, MDMA, (ecstasy) nicotine, and caffeine are all classified as stimulants. Nicotine and caffeine in particular are widely used legal stimulants, whereas amphetamines and MDMA are manufactured in illegitimate labs for illegal sale on the street. Stimulants can cause psychosis, (characterized by hallucinations and delusions) and permanent brain damage. They are extremely addictive, cause cardiovascular problems, (irregular heart beat) anxiety, and high doses can be fatal.
Hallucinogens are drugs that alter a person's perceptions of the world around them. Some say that drugs such as LSD can provide "enhanced introspection" or inner peace.