Distorting the senses and clouding the mind, hallucinogens pose grave dangers; LSD may trigger anxiety, panic, depression, paranoia, and psychotic episodes. PCP prompts violence, can induce psychosis, and cause death by respiratory arrest.

Usually smoked, PCP can also be taken orally, snorted, or injected. It is sold in capsules, tablets, powder, and liquid. Most often the crystalline powder is sprinkled on a leafy substance—tobacco, parsley, mint, oregano, or marijuana—and then smoked in rolled cigarettes.

LSD, commonly called “acid”, is the best known of the hallucinogens. Discovered in 1938, LSD was popular in the late 40’s through the 60’s. During these years many young people took “acid trips.” Advocates thought LSD was a mind-expanding aid that helped users achieve mystical states of perception.

LSD is generally taken orally and in very small doses. Most often, LSD is found in small squares of impregnated paper, called "blotter acid." The squares may come in perforated sheets, like postage stamps, sometimes with an eye-catching image on each square. The drug may also come in tiny tablets, called "microdots," or in small, thin, gelatin squares, known as "windowpane." LSD is sometimes available in a clear liquid solution. This is dispensed with an eyedropper, onto sugar cubes or directly onto the tongue. Another variety, "blue dot acid," consists of paper slips smeared with a blue-colored solution of the drug.

Physical effects of LSD may include: dialated pupils, high temperature, rapid heartbeat, increased blood pressure, sleeplessness, appetite loss, and tremors. Psychological effects can last for 12 hours. During the first 30 to 90 minutes, changes in visual perception and mood are likely. As the drug achieves its one-to two-hour “peak,” the user may experience distorted impressions of time, space, and distance. “Tracking” may occur-the observation of streams of colored light following the path of a moving object and “psychedelic” patterns may appear. Judgment and the ability to recognize immediate danger can be impaired increasing the risk of injury. Acute anxiety, depression, panic, paranoia, or psychotic behavior may accompany a bad trip or may occur after most other effects of the drug have worn off. An overdose can result in a longer, more intense and more frightening trip, and the spontaneous, recurring hallucinations known as flashbacks can occur days, weeks, or more than a year after LSD use.