The expression « To run amok » describes bouts of murderous madness. This clinical entity was originally described in the Malay Peninsula. Associated with a form of exoticism, literary and historical descriptions are available. For about twenty years, amok has been included in psychiatric classifications as a culture-bound syndrome. In the last quarter of the 20th century, some parallels were observed between amok and mass shootings. Although the weapon of choice has changed from dagger to gun, common traits are clearly identifiable. Anger, feelings of prejudice and paranoid thoughts -dominate the picture. The absence of an ideological claim distinguishes the mass shooter from the terrorist. The psychiatrist may have a role in prevention, but these acting outs -remain difficult to anticipate.