Use of hallucinogens produces different signs and symptoms depending on the drug. The most common hallucinogens are LSD and phencyclidine (PCP).

Signs of LSD use include:

  • Hallucinations
  • Greatly reduced perception of reality, for example, interpreting input from one of your senses as another, such as hearing colors
  • Permanent mental changes in perception
  • Rapid heart rate
  • High blood pressure
  • Tremors
  • Flashbacks, a re-experience of the hallucinations — even years later

Signs of PCP use include:

  • Hallucinations
  • Euphoria
  • Delusions
  • Panic
  • Loss of appetite
  • Depression
  • Aggressive, possibly violent behavior