Abstract: We found marijuana addicts showed a varied profile of dangerous and potentially lethal withdrawal symptoms. 82% of them went from being psychologically healthy to showing clear clinical signs of anxiety, depression, post traumatic stress, or obsessive compulsive disorder. These varied psychological withdrawal effects were less responsive to conventional treatment. Patients whose marijuana addiction was concurrent with cancer additionally suffered nausea, vomiting, an increase in pain sensitivity, increased growth rates of tumors and increased morbidity. Marijuana addicted AIDS patients showed a severe reaction that included nausea, vomiting, loss of appetite, wasting, and an inability to comply with medication regimes, which was worse than heroin withdrawal. In addition, marijuana withdrawal caused more subtle effects on music perception and brain function, with many of the musicians and music lovers moving from various abstract, creative genres, to smooth jazz and pop-country, and a decreased tendency to notice and ability to play polyrhythmic music. These withdrawal effects clearly and conclusively show the dangers of marijuana, and demonstrate a particular concern for marijuana in cancer and AIDS patients.