Researchers have long studied the relationship between mental illness and terrorism, particularly lone-wolf terrorists. One study examined ninety-eight lone wolf attackers in the United States, and found that 40 percent of them had identifiable mental health problems, compared with 1.5 percent of the general population.
Another study reviewed 119 lone wolf attackers and a similar number of members of violent extremist groups in the United States and Europe, and found that nearly 32 percent of lone wolves had been diagnosed with a mental illness, while only 3.4 percent of terrorist group members were mentally ill.
The researchers say that there is a significant link between mental problems and the making of a lone-wolf terrorist, leading to cautious hope that future attacks may be avoided. “It’s never an either-or in terms of ideology versus mental illness,” one researcher said. “It’s a dangerous cocktail.”
A study funded by the U.S. Justice Department and conducted by Ramon Spaaij, a sociologist at Australia’s Victoria University, and Mark Hamm of Indiana State University, says that there is a significant link between mental problems and the making of a lone-wolf terrorist, leading to cautious hope that future attacks may be avoided.