In the wake of mass shootings, the perpetrators are often characterized by the media as "insane" or "deranged." A few mass shooters did suffer from severe mental illnesses, notably in the Aurora, CO, theater shooting and the Tucson, AZ, incident that injured Rep. Gabrielle Giffords. The Sandy Hook shooter was never formally diagnosed with a mental illness, although a report issued in the wake of Sandy Hook (PDF) suggested that he may have had multiple undiagnosed mental illnesses.
Following such incidents, calls for changes in mental health services to prevent future incidents often go hand-in-hand with calls for increased gun control. However, mental health professionals caution that such media reports may simply increase public fear of mental illness and discourage those who experience mental illnesses from seeking treatment. They also point out that mental illness is not necessarily a predictor of violence.
Attempts to profile shooters, sometimes in the hope of identifying at-risk individuals before they resort to violence, are common but also contested.