Marijuana comes from the cannabis sativa plant and contains a mind altering (psychoactive) ingredient called THC. It reduces short-term memory, alters sense of time, impedes concentration, increases reaction time, and reduces coordination.
Heroin (and other opiates) are made from the poppy plant and are highly addictive. Heroin clouds mental functioning and depresses respiratory rate.
Cocaine comes from the extract of the Erythroxylon coco bush. It is a stimulant which causes elevated heart rate and blood pressure, aggression, paranoia, chest pain, respiratory failure, and blurred vision.
Crack cocaine is the freebase form of cocaine that can be smoked. It may also be termed rock, hard, iron, cavvy, base, or just crack; it is the most addictive form of cocaine. The effects of crack are very similar to those of cocaine.
Lysergic acid diethylamide, abbreviated LSD, is a psychedelic drug that is known for its psychological effects which can include altered thinking processes, closed and open eye visual hallucinations, and an altered sense of time and space.
Ecstasy is a psychedelic-amphetamine hallucinogen that causes increases in heart rate and body temperature, dizziness, confusion, blurred vision, insomnia, and paranoia.
Phencyclidine, commonly known as PCP, is a drug which is said to reduce or block signals to the conscious mind from other parts of the brain. It produces effects which may include sensory deprivation, dissociation, hallucinations, and dream-like states or trances. It can also cause cognitive and memory impairment and amnesia.