Hallucinogens can be taken orally or injected. Physical effects that follow ingestion of the drugs include increased heart beat, higher blood pressure, raised blood sugar level and irregular breathing. Psychological effects range from a sense of euphoria to panic and violent behavior. Psychological states in between can include the loss of ability to separate fact from fantasy as well as hallucinations and paranoia. Hallucinogens affect levels of certain chemicals in the brain and change the electrical activity of the brain.
Hallucinogens are illegal.
Withdrawal effects of hallucinogens can last from 8 to 12 hours and can recur suddenly to frequent users without additional drugs. Users may feel intensely depressed leading to strong suicidal urges or may have delusions of invulnerability. There is some evidence that use of LSD may cause permanent damage. One danger of the various hallucinogens is that they are very unpredictable. There may be exhilaration and withdrawal from reality, or panic and suicidal feelings.