The effects of hallucinogens can begin within 20 to 90 minutes and can last as long as 6 to 12 hours. Salvia’s effects are more short-lived, appearing in less than 1 minute and lasting less than 30 minutes. Hallucinogen users refer to the experiences brought on by these drugs as “trips,” calling the unpleasant experiences “bad trips.”
Along with hallucinations, other short-term general effects include:
increased heart rate
nausea
intensified feelings and sensory experiences
changes in sense of time (for example, time passing by slowly)
Specific short-term effects of some hallucinogens include:
increased blood pressure, breathing rate, or body temperature
loss of appetite
dry mouth
sleep problems
mixed senses (such as “seeing” sounds or “hearing” colors)
spiritual experiences
feelings of relaxation or detachment from self/environment
uncoordinated movements
excessive sweating
panic
paranoia—extreme and unreasonable distrust of others
psychosis—disordered thinking detached from reality
Little is known about the long-term effects of hallucinogens. Researchers do know that ketamine users may develop symptoms that include ulcers in the bladder, kidney problems, and poor memory. Repeated use of PCP can result in long-term effects that may continue for a year or more after use stops, such as:
speech problems
memory loss
weight loss
anxiety
depression and suicidal thoughts