PCP was originally introduced as an anesthetic in the 1950s but by 1965 was no longer in medical use because of its horrific side effects. Most hallucinogens have their primary effects on serotonin, one of the brain’s many neurotransmitters, but PCP, like ketamine, impairs the transmitter glutamine and is far more dangerous and long lasting in effect than other hallucinogens. It is known to cause structural lesions, as well as chemical changes, in the brains of rats.2 —
