In some of these studies, there have been found an increased rate of mental disorders among terrorists, compared to a normal population. These findings apply to terrorists who act on their own, so-called solo terrorists. The conclusions are seldom based on researchers’ own diagnosis, but rather on other source material, such as court documents and media reports. This makes the findings somewhat uncertain. At the same time, research finds no basis for saying that terrorists who are part of groups have increased degrees of mental disorders. This is related to the necessity of proper functioning of group members if they are to be regarded as a useful resource for the group. Solo terrorists, on the other hand, may increasingly have psychological problems or be mentally unstable as they commit terrorist acts. It is also argued that radicalization and participation in terrorism itself can lead to mental disorders.
The studies nevertheless observes that radicalization and terrorism arise from complex processes, often at individual, group and community level. In order to prevent and eliminate radicalism and terror, it is therefore necessary to take action at all these levels.