When terrorism meets mental health

August 26, 2021

Cátia de Carvalho

In the final days of June 2021, a 24-year-old man from Somalia, attacked several people with a knife in the German city of Wurzburg, leaving three people dead and 5 people severely wounded. The suspect was on the radar of the police authorities and had a psychiatric record, having been admitted to a psychiatric hospital days before the attack.

The police investigation showed that he acted alone and that he had, in his home, jihadist propaganda, pointing out that the attack might have been a result of political motivation and not (only) of a psychiatric condition. When terrorism meets mental health, several questions arise to ascertain and perceive which determinant is more important – political motivation or psychiatric condition – in the planning of and in the moment of the attack.

The study of terrorism and mental health

The quest for understanding terrorism and radicalisation is marked by three stages throughout the last decades (Corner & Gill, 2015; RAN, 2019a). In the 1970s and 1980s, specialists searched for pathological explanations for terrorist behaviour, but they concluded that terrorists were neither psychopaths nor psycopathologically ill, or at least the majority. Rather, most terrorists would commit violence rationally and deliberately and this inaugurated the second stage of studies.

Recently, researchers concede that terrorists are a diverse and complex population and some of them have mental health problems.

From the 1990s to the 2000s, researchers dismissed the psychopathology approach to terrorism and focused instead on the group dynamics and social psychology to explain terrorism and radicalisation. Recently, in the 2010s, researchers concede that terrorists are a diverse and complex population and some of them have mental health problems, such as schizophrenia, depression, and personality disorders (Corner, Gill & Mason, 2016; O’Driscoll, 2018).

Corner and Gill (2015) analysed a population of 119 lone-actor terrorists – which, like the Wurzburg attack extremist, has been the main modus operandi in Europe in the last years (Hamm & Spaaij, 2017) – and concluded that the probability of a mental disorder is 13.49 times higher in lone-actors than in group actors. Moreover, the Radicalisation Awareness Network (RAN, 2019c) goes beyond this to state that mental health problems are a precondition for any extremist violence. This calls for attention on mental health issues being introduced in the equation again, not only in the treatment practices but also in the prevention efforts and policies.

The problem with lone actors

Even though the terminology “lone actors” has been widely used to describe people who prepare and commit terrorist attacks alone, this concept must be used with caution. Early research suggested that lone actors would radicalise, plan, and commit terrorist attacks alone, however recent findings indicate otherwise (Hofmann, 2020). Research carried out by Schuurmann and colleagues (2019) shows that the lone actors' terminology should be reconsidered since lone actors have often engaged in radical environments, both online and offline, and social ties play an essential role. Like Schuurmann and colleagues, other scholars have shown that the so-called lone actors are influenced by social interaction during the process of radicalisation and that they share their intentions (long) before committing the attack (Spaaij, 2012; Hofmann, 2020).

These two key features of lone actors’ behaviour show that they are detectable and can be identified in time by police authorities before committing a terrorist act. On the other hand, it is worth noting that, while most of the so-called lone actors are not so alone as they might look like and, therefore, are detectable, there are a few cases of terrorists who have, indeed, acted all alone and have not shared their intentions before committing the act, like Anders Breivik and Ted Kaczynski (Schuurmann et al, 2019). 

Although the terminology is questioned, it is relevant to note that, as Corner and Gill (2015) showed, the population of lone actors display a higher prevalence of mental health problems, than that of group actors. This also should be considered with caution, since the loneness feature might be a change during the radicalisation process, rather than a personal characteristic of these individuals (Schuurmann et al, 2019). In any case, it is worth considering the inclusion of mental health in both the prevention of extremism and in the risk assessment efforts.

Mental health and its inclusion in the P/CVE approach

Preventing and countering violent extremism (P/CVE) is a complex task, due to the multitude of factors that are at play. Given this complexity, the mental health issues in the P/CVE have been explored by academics and practitioners. Therefore, research shows that autism spectrum disorder, delusional ideas and schizophrenia are some of the mental health issues that play a role in the radicalisation process and that might trigger violence (O’Driscoll, 2018; RAN, 2019a, RAN 2019c).

It should be taken into consideration that oversimplifying and overvaluing the role of mental health issues in violent extremism might be a risk.

However, it should be taken into consideration that oversimplifying and overvaluing the role of mental health issues in violent extremism might be a risk. As stated by researchers and practitioners, mental health is just another risk factor, that should not be overvalued, since it is not possible to identify someone at risk of radicalising or committing violence only by looking at mental health determinants alone (RAN, 2019a; Kenyon et al., 2021).

It is undeniable the role of mental health, but caution is needed, since it can stigmatise and cause more harm to people who are already vulnerable, or it can accelerate the vulnerability to radicalisation (RAN, 2019a). Thus, policies and interventions should be based on evidence to inform best practices and prevention efforts should be done on a multi-agency basis, tackling all risk factors, for better results (RAN, 2019c).

The role of social dynamics and its interplay with mental health

The role of mental health must be considered in conjunction with other factors, like the social context, and group dynamics. As stated by RAN (2019c), mental health disorders might be accelerated by contextual conditions, like marginalization, different forms of discrimination, social exclusion and social deprivation. These group dynamics, which are known to trigger radicalisation when at play with other risk factors, might have an impact on the psychological well-being of people who are about to be radicalised (Gill, et al, 2021; Vergani et al, 2020).

Thus, protective factors, like emotional regulation, resilience, coping strategies, and others, must be strengthened and included in interventions. Given the interplay between mental health and group dynamics, prevention strategies and policies must follow the whole-society approach (RAN, 2019c).

The public health model of prevention of extremism

The interplay of mental health disorders and terrorism shows the complexity and obstacles in assessing and countering this phenomenon, as well as the need for a comprehensive and holistic approach. It also shows the need to include an appreciation of wider society in the prevention of violent radicalisation, since a focus only on group dynamics or only on mental health issues might make it more difficult for police authorities to identify threats in time and for practitioners to lead effective interventions. Hence, P/CVE must rely on different types of interventions and multidisciplinary teams, depending on the target group and the level of involvement in extremism.

A way to promote such comprehensive prevention efforts is to adopt the public health model to violent extremism (Weine et al. 2017; RAN, 2019b; RAN, 2019c). This model layers prevention in three different stages, following the structure of a pyramid. The base is the primary prevention, which comprises the whole community. The idea is to prevent exposure to risk factors, promote protective factors, strengthen social ties and integration, alleviate social inequalities, and develop active citizenship. Concerning mental health issues on this level, intervening early is of great importance to promoting integration in society. This can only be achieved for all if, for example, social inequalities are mitigated.

Above this stage, there is secondary prevention, which aims to intervene with people who are at increased risk of extremist behaviour and the focus is on preventing escalation to violence. In this case, the prevention must focus on initiatives to reduce risk with vulnerable people, and they must rely on the coordinated work developed in conjunction by several services, like local authorities, schools, health services and social services, to mitigate the already existing risks and to make sure that the most effective intervention is designed accordingly to the situation. Only this way it is possible to promote mental health and psychosocial well-being as well as prevent causing more harm.

P/CVE must rely on different types of interventions and multidisciplinary teams, depending on the target group and the level of involvement in extremism.

In the tertiary prevention, the final stage, the intervention is directed at people who are already violently radicalised or at risk to commit violence, therefore, efforts to help people to deradicalise and/or disengage from violence must be adopted to rehabilitate and reintegrate them back into society. When designing such interventions, tackling mental health issues must be considered too, since only promoting the full psychosocial well-being can contribute to making these efforts successful.

A key feature of this model concerns the involvement of the community and the use of already existent resources, namely school teachers, health professionals, psychologists, academics, local authorities, social assistants, among others. The aim is to create multiagency and multidisciplinary teams which, together, address violent extremism, but also other social concerns, such as other criminal activities, mental health problems, or social inequalities. Thus, by intervening early on these concerns, it is possible to promote protective factors and to avoid some situations from escalating to violence. Ultimately, the adoption of this model allows the development of a more secure, healthy, and inclusive society.

Governments should invest in a coordinated comprehensive work of awareness and prevention to avoid violent acts, namely those that usually might not be identified early, to promote psychosocial well-being, and close cooperation with academia to substantiate the prevention efforts on scientific evidence.


Corner, E., & Gill, P. (2015). A false dichotomy? Mental illness and lone-actor terrorism. Law and Human Behavior, 39(1), 23-34.

Corner, Emily; Gill, Paul & Mason, Oliver (2016). Mental health disorders and the terrorist: A research note probing selection effects and disorder prevalence. Studies in Conflict and Terrorism, 39 (6), 560-568. doi: 10-1080/1057610X.2015.1120099.

Gill, P., Clemmow, C., Hetzel, F., Rottweiler, B., Salman, N., Van Der Vegt, I., Marchment, Z., Shumann, S., Zolghadriha, S., Schulten, N. Taylor, H. & Corner, E. (2021). Systematic review of mental health problems and violent extremism. The Journal of Forensic Psychiatry and Psychology, 32 (1), 51-78. doi: 10.1080/14789949.2020.1820067

Hamm, M. & Spaaij, R. (2017). The age of lone wolf terrorism. New York: Columbia University Press.

Hofmann, D. (2020). How “alone” are lone-actors? Exploring the ideological, signaling, and support networks of lone-actor terrorists. Studies in conflict and Terrorism, 43(7), 657-678. doi: 10.1080/1057610X.2018.1493833

Kenyon, J., Baker-Beall, C. & Binder, J. (2021). Lone-actor terrorism – A systematic literature review. Studies in Conflict and Terrorism. doi: 10.1080/1057610X.2021.1892635

O’Driscoll, D. (2018). Violent extremism and mental disorders. K4D Helpdesk Report. Brighton, UK: Institute of Development Studies. Retrieved from: https://assets.publishing.service.gov.uk/media/5c700673ed915d4a3e8266e7/476_Violent_Extremism_and_Mental_Disorders.pdf

Radicalisation Awareness Network (2019a). Understanding the mental health disorders pathway leading to violent extremism. Ex-Post paper. Turin, 13 March. Retrieved from: https://ec.europa.eu/home-affairs/sites/default/files/what-we-do/networks/radicalisation_awareness_network/about-ran/ran-h-and-sc/docs/ran_h-sc_understanding_the_mental_health_190313_25_en.pdf

Radicalisation Awareness Network (2019c). A mental health approach to understand violent extremism. Ex-Post paper. Paris, 3 July. Retrieved from: https://ec.europa.eu/home-affairs/sites/default/files/what-we-do/networks/radicalisation_awareness_network/about-ran/ran-h-and-sc/docs/ran_hsc_prac_mental_health_03062019_en.pdf

Radicalisation Awareness Network (2019c). Taking mental health insights into account in local P/CVE. Ex-Post paper. Paris, 29 May. Retrieved from: https://ec.europa.eu/home-affairs/sites/default/files/what-we-do/networks/radicalisation_awareness_network/ran-papers/docs/ran_local_hsc_taking_mental_health_28052019_en.pdf

Schuurmann, B., Lindekilde, L., Malthaner, S., O‘Connor, F., Gill, P. & Bouhana, N. (2019). End of lone wolf: The typology that should not have been. Studies in Conflict and Terrorism, 42 (8), 771-778. doi: 10.1080/1057610X.2017.1419554

Spaaij, R. (2012). Understanding lone wolf terrorism: Global patterns, motivations and prevention. Dordrecht: Springer.

Vergani, M., Iqbal, M. Ilbahar, E. & Barton, G. (2020). The three Ps of radicalization: Push, pull and personal. A systematic scoping review of the scientific evidence about radicalization into violent extremism. Studies in Conflict and Terrorism, 43 (10). doi: 10.1080/1057610X.2018.1505686

Weine, S., Eisenman, D., Kinsler, J., Glik, D. & Polutnik, C. (2017). Addressing violent extremism as public health policy and practice. Behavioral Sciences of Terrorism and Political Aggression, vol. 9 (3). doi: 10.1080/19434472.2016.1198413

Written by: Cátia de Carvalho

Cátia de Carvalho is a PhD candidate at the Faculty of Psychology and Education Sciences of University of Porto. Since 2014 she has been studying terrorism, radicalisation, and integration of migrants and minorities. Her doctoral project focuses on the protective factors of the Portuguese society against violent radicalisation. She was recently appointed as a RAN expert and is a former visiting student at the Institute of Criminology of the University of Cambridge.

The opinions expressed here are the author's own and should not be taken to represent the views of the DRIVE project.
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