The nascent empirical literature on psychopathology and terrorism

The current status of empirical knowledge regarding the relationship between psychopathology and violent radicalization has undoubtedly improved from the initial forays into the study.

Work during the 1970s and 1980s focused upon personality traits and disorders, especially three that are found within DSM cluster B: borderline, narcissistic and antisocial. Poor research designs and a lack of valid empirics ultimately undermined such arguments. Various studies supporting psychopathic and personality‐level explanations were conducted in the absence of rigorous clinical diagnostic procedures. Instead, they relied upon autobiographies, biographies, second‐hand case studies, media interviews and willful misreadings of actual empirical work.

In the absence of rigorous clinical and empirical procedures, the reductionist view, where terrorists are characterized as suffering from some mental disorder purely on the nature of the attack behavior, ignores the highly complex neurological, psychological and sociological processes whereby actors become desensitized to violence, and subsequently suffer psychological consequences as a result of terrorist engagement.

Despite these methodological problems, the appeal of such efforts remains influential within the literature beyond their zenith in the 1970s and 1980s. For example, studies continue to hypothesize that terrorists are driven by envy, an urge to punish and retaliate, and a lack of empathy1.

Following movements in wider psychiatric research, the study of the terrorist has also recently become more disaggregated, with empirical analyses focusing upon specific terrorist subsets (e.g., lone‐actors, foreign fighters) rather than aggregate depictions (i.e., the general terrorist). Such analyses identify a mid‐way point between the initial attributional studies that sought causation in psychopathology and social explanations which overlook the potential of psychopathology.

Such studies have found evidence for the presence of mental and personality disorders with various degrees of methodological sophistication. Some simply report aggregate prevalence rates of mental disorder diagnoses. Others disaggregate across mental disorders and compare to the societal base rate. One study of 140 Dutch foreign fighters and attempted foreign fighters found that 6% had diagnosed disorders. These included psychotic, narcissistic, attention‐deficit/hyperactivity, schizophrenia, autism spectrum, and post‐traumatic stress disorders. An additional 20% displayed indications of other undiagnosed mental health problems2.

An investigation examining 153 lone‐actor terrorists also noted a diverse range of disorders, including traumatic brain injury, drug dependence, schizophrenia, schizoaffective disorder, delusional disorder, psychotic disorder, depression, bipolar disorder, unspecified anxiety disorder, dissociative disorder, obsessive‐compulsive disorder, post‐traumatic stress disorder, unspecified sleep disorder, unspecified personality disorder, and autism spectrum disorders. The authors noted that schizophrenia, delusional disorder and autism spectrum disorders were more prevalent than in the general population3.

Other studies examine statistical associations between disorder prevalence and specific behaviours and experiences. One investigation identified that lone‐actors with a mental disorder are more likely to express violent desires, seek legitimization for their intended actions, stockpile weapons, train, carry out a successful attack, kill and injure, discriminate in their targeting, and claim responsibility4.

The study of psychopathology and terrorism has traditionally focused upon those who conducted, or at least attempted to conduct, violence. Those studies that instead focus upon individuals who hold attitudinal affinity with such cases are growing. These studies further highlight the importance of examining personality alongside several other personal, situational and attitudinal measures.

A study of 52 teenagers in Gaza highlighted that depressive symptoms were common amongst supporters of “religio‐political aggression”5. One investigation developed a radicalization scale that asked 16 questions regarding sympathies for violent protest and terrorism. Of the 608 UK‐based participants, those most sympathetic were significantly more likely to also self‐report depression and to see religion as important. Condemnation of violent protest and terrorism was associated with a greater number of social contacts, less social capital, and an unavailability for work due to housekeeping or disability. There was no significant difference in terms of generalized anxiety scores6.

A European investigation deployed an extremist attitudes scale to 1,288 adolescents in Switzerland. Personal strain (which included personal stressors, negative life events and prior stays at a psychiatric hospital) was associated with significantly higher support for violent extremism, although this effect largely disappeared once other social and individual variables were included in the analysis. Those with poor coping skills were significantly more likely to support violent extremism. Self‐reported low self‐control had no impact upon violent extremism7.

The above investigations have value, as they identify disorders and symptoms which often co‐occur with specific experiences. However, “detailed research would be needed to further clarify the precise nature and role (if any) of mental health problems in the development of violent activity”8. In many cases, active symptoms may be present, but completely unrelated. Additionally, even symptoms of disorders that are associated with an increased risk of violence (e.g., substance use and active psychosis) may never give rise to an act of violence until they are combined with environmental factors that favor violence, in the context of a situational trigger.

Although this perspective is theoretically coherent, research is yet to empirically determine at which point the experience of psychiatric symptoms is relevant to violent radicalization. Depending on circumstance, it may be a catalyst, an inhibitory factor, and even a consequence. To improve this knowledge gap, and move forward from unfounded causal assumptions, research must look to multiple avenues.

This may include, but is not necessarily limited to: a) sequence modelling to understand when the onset of disorders typically occurs in an individual's move to radicalization and violent action; b) clinical interviews with those at risk of radicalization as well as imprisoned terrorists; c) an exploration of how prominent symptoms were at the time of the violence and their relevance in decision‐making; d) evaluations of psychologically‐oriented interventions countering violent extremism; e) investigating the impact of living a terrorist lifestyle upon psychological functioning; and f) examinations of whether and how the presence of psychopathology impacts recruitment into terrorist co‐offending networks.

Emily Corner1, Paul Gill2
1Centre for Social Research and Methods, Australian National University, Canberra, Australia; 2Department of Security and Crime Science, University College London, London, UK