Hi, Usually, a person submits a urine specimen for the detection of Marijuana in the body. Duration of detection varies from 7-30 days and depends on the chronicity of exposure. False positives have been reported when taking proton pump inhibitors, nonsteroidal anti-inflammatory drugs, as well as other medications. Symptoms after Marijuana use include-vomiting, unsteady gait, delirium, psychosis, anxiety. Chronic use in adolescents is associated with poor academic performance (including less likely to graduate from high school), adult psychotic disorders, and other illicit drug use and drug addiction. I hope by sharing this information that you will see the dangers of this drug and what it can do to you acutely as well as how it can affect the quality of your life. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Arnold Zedd, Pediatrician