Violent extremism can take many forms. From coup attempts to violent uprisings, ethnic cleansing and acts of terrorism, current global events painfully remind us that political violence is still prevalent and remains a threat to global peace and democratic existence. For more than a century, psychologists have sought to understand what drives people to participate in collective violence. In the search for causes and potential remedies to the social ill that is political violence, the role of mental health has been a hotly debated topic.

Initially, psychologists drew on the idea of "dysfunctional" personality traits to explain the rise of fascism, communism, and other violent ideologies. For instance, Theodor Adorno proposed that people with authoritarian personalities are attracted to violent extremist ideologies and commit horrible acts in the service of those ideologies. Other researchers emphasized the ordinariness of people who engaged in extremely violent actions. This view was seemingly vindicated by the infamous Obedience Experiments conducted by Stanley Milgram in the 1960s, which showed that a substantial majority of law-abiding citizens could be led to inflict deadly torture on random strangers if the context was favorable.

This debate around the (non)pathological nature of violent extremists has continued for the past 50 years. The search for a "terroristic personality" has failed. Incarcerated terrorists and former terrorists have rates of psychiatric diagnoses similar to non-terrorists. Likewise, the association between radical attitudes and mental health symptoms like depression or anxiety remains inconsistent. Psychologists have concluded from this research that pretty much anyone could be radicalized into violent action, given the "right" set of circumstances.

However, recent research has identified new personality characteristics, such as the tendency to seek social status and significance (a sense of social worth, dignity, and mattering) that predict violent extremism.

Recent meta-analyses, which combine the results of many previous studies to provide a more accurate sense of what the literature shows, have revived the idea that some individuals are more prone to violent extremism. Indeed, the largest predictor of violent ideological intentions is a form of ideological obsession. 

People with ideological obsession have a dysfunctional relationship to their ideology. Whereas a functional relationship with religion or politics predicts "healthy" forms of engagement such as legal demonstrations and peaceful activism, obsessive involvement with religion and politics leads to a withdrawal from family and friends, and engagement in violent forms of action, such as looting during riots. Although ideological obsession is not a pathology in itself, it shares striking features with symptoms of obsessive-compulsive disorder (OCD): spending a lot of time thinking ideological thoughts and feeling that ideological involvement is compulsive.

These findings led us to hypothesize that ideological obsession is linked with OCD symptoms, and that OCD symptoms are therefore linked with political violence.

To test this idea, we distributed an online survey to 1,114 people from various ideological and religious groups in the United States, including environmental activists, Republicans, Democrats, and Muslims. We measured OCD symptoms, ideological obsession, intentions to act violently for one's ideology, and a host of other factors.

In line with our hypothesis, OCD symptoms consistently predicted ideological obsession and violent intentions. This link was robust even when we accounted for demographic characteristics such as age, gender, other mental health issues such as substance abuse, and other personality characteristics.   Some (but far from all) people with OCD symptoms may direct their symptoms to their ideology, and this may, in turn, foster violent intentions.

These findings demonstrate for the first time that mental health symptoms may contribute to violent extremism. We think they are important because, unlike personality traits or environmental factors, psychologists know how to treat OCD symptoms with cognitive behavioral therapy. Our results suggest promising avenues for the development of psychological interventions against radicalization that do not target ideology directly (which is very hard to change).

On a final note, we urge caution when interpreting our findings. OCD symptoms are at most a risk factor for radical intentions. Our findings do not mean that people with a diagnosis of OCD are more violent than others. Furthermore, the link between OCD symptoms and violent intentions is nowhere near strong enough to suggest that terrorists cannot be held legally responsible for their actions.  

For Further Reading

Adam-Troian, J., Bélanger, J. J. (2023). "Consumed by creed": Obsessive-compulsive symptoms underpin ideological obsession and support for political violence. Aggressive Behavior, 1–11.

Jais Adam-Troian is an Assistant Professor of Psychology at Heriot-Watt University Dubai. His research investigates the psychology of (de)radicalization, violent extremism, and conspiracy beliefs.