Over 50 percent of people will use marijuana sometime in their life. While intoxication lasts two to three hours, the active ingredient in marijuana, delta-9-tetrahydro-cannabinol, can accumulate in fatty tissues, including the brain and testes. Adverse effects from marijuana use include decreased coordination, epithelial damage to the lungs, increased risk of infection, cardiovascular effects and cognitive deficits. Unexplained behavior changes, altered social relationships and poor performance at school or work can signify a drug problem. Treatment requires a combination of education, social support, drug monitoring and attention to comorbid medical and psychiatric conditions.