Overview: Lots of people wished it would disappear forever, but PCP never really went away after its disastrous heyday in the 1970's. The drug (known chemically as phencyclidine, but better known on the street as angel dust) only ducked underground, waiting for its reputation as a bummer drug to die down.

Apparently, it did -- for a while, at least -- because a few years ago, while no one was looking, PCP was suddenly back -- this time, mixed with formaldehyde and dripped onto cigarettes in a mind-numbing concoction known as "wet." That's when an all-new generation got its own chance to find out about a nasty, old-school problem drug.

Street Names: Illy, wet, hydro, fry, matrix, dank, amp, or sherms, depending on area.

Appearance: Ordinary cigarettes are dipped in a PCP solution, or loose tobacco or marijuana is saturated, dried, and rolled into cigarettes.

Actions/Effects: Developed as a surgical anesthetic, PCP was abandoned medically (except for veterinary use) because of its bizarre psychological effects in human beings. Effects vary widely, often combining stimulant, depressant, anesthetic, and hallucinogenic drug properties.

Risks/Side Effects: The effects of PCP are extremely broad, and vary depending on dose:

• Low Doses: PCP triggers feelings of stimulation, euphoria, and lowers inhibitions at low doses. It also causes sweating, impaired coordination and judgment, and slurred speech.
• Moderate Doses: At higher doses, central nervous system activity slows further, resulting in a confused, numb intoxication. Body image distortion and reduced sensitivity to pain are also common.
• High Doses: CNS effects intensify and include agitation, aggression, paranoia, hallucinations, delusions, and insensitivity to pain. Blood pressure drops sharply, accompanied by muscular rigidity and convulsions, leading even to coma and death.

Other risks are linked to the "toxic behavior" of PCP users. Due to the delusions and sensory distortions fueled by PCP, users may initiate acts of violence, or become victims of such mishaps as fires and drownings.

Trends: As trends go, "wet" seems to have come and gone, as numbers on several national surveys, tracking use and problems linked to the drug, have declined recently.

Demographics: Although a national survey showed a 4 percent rise in PCP use between 1999 and 2000, and E.R. admissions involving the drug soared 47 percent during the same period, numbers in both categories have fallen sharply in the years since. In a 2005 study, prior-year use of PCP fell 22 percent, to its lowest level in years.