Lecture – Lone-Actor Terrorism – Clinical and Behavioral Patterns

Available with English captions.

Presented by Jacob C. Holzer, MD, McLean Hospital – McLean Forum lecture

Lone-actor terrorism has had a significant adverse impact on society in the U.S. and abroad. These incidents have led to an increase in research into the clinical and behavioral patterns of this group of terrorists.

In this talk, Holzer reviews literature and preliminary studies to identify common characteristics and trends across various lone-actor terrorism cases.

He defines lone-actor terrorists as one or two individuals who commit to or plan to enact violence. This violence usually takes place in a public place or in a government setting. There is broad variability in ideologies and geopolitical contexts behind these violent incidents, but most are linked to a specific ideology or cause.

Watch now to learn more about:

  • Variables in a lone-actor terrorism case
  • Behavioral and mental health issues related to lone-actor terrorism
  • Variability in ideologies related to cases

Holzer reports that most of these people are isolated at a young age. As they grow older, they undergo some kind of radicalization, which alters their thinking and leads them toward violence. Rhetoric and the impact of the internet and social media are often connected to incidents of lone-actor terrorism.

Drawing on academic literature, case studies, and his own background in forensic psychiatry, Holzer details common characteristics of lone-actor terrorists. Findings show that many individuals have a vulnerability to act violently and take matters in their own hands. Also, mental health issues and underlying thoughts of harassment and victimization are common.

Holzer reports that many individuals have a history of maladjustment and poor functioning in the military or at work. In addition, lone-actor terrorists are often seen as odd, atypical, or changed to others around them.

Building on these findings, Holzer reviews behavioral and clinical variables common to lone-actor terrorists. He compares those characteristics to those who join larger, more organized terrorist groups, and he compares rates of diagnosed mental illness among both groups of terrorists. He also looks at possible associated behavioral mechanisms behind violent acts.

Finally, Holzer discusses federal and state “not guilty by reason of insanity” defense statues and explains how they are applied to lone-actor terrorism cases.