Cocaine and marijuana are two of the most commonly used drugs in the country, and have very different effects on brain function. In a periodical on marijuana and psychosis1, the main topic is whether or not THC, the main psychoactive ingredient of marijuana, can even cause schizophrenia or any other type of psychosis. It seems that there have been very few studies which have linked marijuana use with psychosis, although there seems to be a correlation between the use of marijuana and occurrence of psychosis. This correlation is likely to do the use of drugs whose use is linked with marijuana.