Most of the mass murderers were not mentally ill
Contrary to popular belief, most of the perpetrators of mass murders were not mentally ill. Such conclusions were reached by a research team from the Center of Prevention and Evaluation and the New York State Psychiatric Institute.
A study based on an analysis of 1,315 mass murder cases around the world found that only 11% of the perpetrators had serious mental disorders or diseases. Among perpetrators using firearms, the percentage of people with mental illnesses was 8%. In turn, the perpetrators using other means (explosives, poisons, knives, vehicles) suffered from this type of ailments in 18%.
The study shows that it is wrong – albeit often repeated in public debate - to define all the perpetrators of terrorist attacks or mass murders as "mentally ill" people. This kind of narrative can lead to stigmatization of people with mental illnesses or disorders.
Research has shown that the perpetrators' actions were much more influenced by their problems with the law, alcohol and drug abuse, as well as traumatic experiences and other problems in private life. High public awareness in this regard can help to identify behaviors indicative of radicalization that are often not associated with mental illness. The ability to properly identify and counter radicalization is essential to prevent terrorist threats.