Mental illness creates a unique challenge for police. Changes in medical infrastructure have left many mentally ill without adequate access to resources or treatment. They often face additional challenges of substance abuse and homelessness. This has led to increasingly frequent contact with police and a shift from mental illness being treated as a health problem to being treated as a police problem. Police are unable to provide treatment, and are frustrated by the amount of their time consumed by persons with mental illness (PMI) and by the amount of time and effort it takes to connect them with treatment. Due to the unpredictable behavior often caused by mental illness and the way police are trained to deal with uncooperative behavior, persons suffering from mental illness are subject to the use of force by police at a disproportionate rate. Police are trying to combat these problems with the implementation of advanced training and the development of Crisis Intervention Teams and Mobile Response Units, as well as increasing connections with local medical facilities to promote treatment over arrest. Other strategies have been experimented with, both in the United States and across the globe, but there is currently a limited amount of research on how effective these programs are. Anecdotally, the most successful programs seem to be those that take a comprehensive approach to mental illness, creating solutions that include police, medical facilities, courts, dispatchers, first responders, and the community. Due to the limits of programs confined to one institution, it is recommended that treatment be expanded and police receive advanced training in dealing with mentally ill people, as well as involving others in the criminal justice and medical communities so that they provide a coordinated response to PMI.