Moderate to high doses of alcohol cause marked impairments in mental functions, severely affecting a person's ability to learn and remember information. Very high doses cause respiratory depression and death. If combined with other depressants of the central nervous system, much lower doses of alcohol can be fatal. Illicit drugs - drugs interfere with the brain's ability to take in, sort and synthesize information. They distort perception, affect sensations and impair memory.
Cocaine can produce psychological and physical dependency.
Effects of the use of crack include increased pulse rate, insomnia, loss of appetite, tactile hallucinations, paranoia and seizures. Crack is far more addictive than heroin or barbiturates. Repeated use of crack can to lead to addiction within a few days. Continued use can produce violent behavior and psychotic states similar to schizophrenia. Cocaine in any form, but particularly crack, can cause sudden death from cardiac arrest or respiratory failure.