It is very unlikely for a person to overdose and die from marijuana use. However, people can and do injure themselves and die because of marijuana's effects on judgment, perception, and coordination, for example, when driving under the influence of the drug. In fact, marijuana was a factor in over 370,000 visits to the emergency department in 2009. About two-thirds of those patients were male, and 12% were teens ages 12 to 17.7
Additionally, people can experience extreme anxiety (panic attacks) or psychotic reactions (where they lose touch with reality and may become paranoid).
7. Reference: Substance Abuse and Mental Health Services Administration. Office of Applied Studies. Drug Abuse Warning Network, 2009: National Estimates of Drug-Related Emergency Department Visits. DHHS Publication No. (SMA) 11-4659, DAWN Series D-35. Rockville, MD, 2011. Available at http://www.drugabuse.gov/publications/research-reports/marijuana/what-scope-marijuana-use-in-united-states.