Symptoms include dizziness, sleeplessness, and anxiety. Use can also lead to psychosis, hallucinations, paranoia, and even a physical collapse. Depressants and Barbiturates Depressants and barbiturates can cause physical and psychological dependence that can lead to respiratory depression, coma and death, especially when used in concert with alcohol. Withdrawal can lead to restlessness, insomnia, convulsions, and possibly death. Hallucinogens LSD, PCP, mescaline, and peyote are classified as hallucinogens.
Hallucinogens interrupt the brain messages that control the intellect and keep instincts in check.
Large doses can produce convulsions and coma or heart and lung failure. Chronic users complain of persistent memory problems and speech difficulties for up to a year after their use. Because the drug stops the brain's pain sensors, drug experiences may result in severe self-inflicted injuries. Persistent memory problems and speech difficulties may linger. Narcotics Users of narcotics, such as heroin, codeine, morphine, and opium, develop dependence and increase the likelihood of an overdose that can lead to convulsions, coma, and death.