BBC had an excellent piece covering research on the number of violent crimes that are linked to people with serious mental disorders. Researchers in Sweden examined 13 years worth of crime data and found that just over 5% (1/20) of all violent crimes in that period of time were committed by people with severe mental disorders (schizophrenia, etc). This came as somewhat of a surprise to the researchers, and I would believe also to most people reading that information. Part of this surprise is the stigma and fear surrounding mental illness. Many people become fearful of violence when they encounter someone who is experiencing symptoms from one of these disorders, but the fact is those folks are much more likely to be the victims of violence than perpetrators.