Thematic series were introduced to BJPsych Open by the current Editor-in-Chief to address key topics in psychiatry and mental health, specifically considering the impact on the global burden of diseases with associated treatments, outcomes, policy and research priorities. The increasing submission to BJPsych Open of articles about the psychosocial and mental health impacts of terrorism and collective violence naturally led to this thematic series. This paper introduces the journal’s series of published papers about terrorism and collective violence. While we identify the topics covered by the series and hope to generate conversation, this paper does not report a systematic review of the series. The thematic series consists of 13 articles; 9 were open submissions and 4 were commissioned. They include this review, an editorial concerning research methods and 11 papers reporting how people have responded to terrorist and violent incidents in 4 countries. Including this review, one paper was published in 2020, three in 2022, two in 2023, five in 2024 and two in 2025. The commissioned papers were added to broaden coverage of the Utøya attack on young people in Norway, and the shootings in Christchurch, New Zealand in 2019. Our intention was to enable the papers on these two incidents to sit alongside papers already submitted about them and the Manchester Arena bombing as well as articles about attacks in Germany. We begin by introducing the papers and comment in the discussion on a series of topics that we have selected as prominent in the series.

How do counterterrorism policies enable terrorist groups to thrive and survive? This article examines the relationship and how counterterrorism policies and political structures impact terrorist group success. While studies of terrorism have tended to separate the two phenomena, there is considerable complexity in the interactions between violent action and coercive state response. To demonstrate the complexity of these interactions, this article examines the persistence of three transnational terrorist groups from 1989 to 2022 – the Lashkar-e-Taiba, Jaish-e-Mohammad, and the Hizbul Mujahideen – that operate in the Kashmir region despite India’s coercive counterterrorism policies. While existing research emphasises macro-level factors in transnational terrorism, this article, based on original qualitative data, demonstrates the critical importance of granular, localised opportunities for terrorist groups to carry on. We show how these structures interact with civilian perceptions of state legitimacy and security to create nuanced patterns of support. In doing so, we challenge simplistic explanations of terrorist recruitment and resilience. The article dispels existing misconceptions about the efficacy of coercive counterterrorism to end militant groups and further suggests that softer, non-coercive approaches might not necessarily generate public sympathy. In fact, select counterterrorism policies might inadvertently legitimise violence by extremist groups to their constituency and increase sympathy in the process.

Research on the political consequences of terrorism often finds a rally around the flag effect: terrorist attacks, as other types of threats, tend to produce spikes in popularity and support for the incumbent, as citizens turn to those in power seeking protection. Most research, however, is based on single case studies that analyze very salient attacks from international terrorist organizations. Even if these studies are well identified, the question of generalizability remains, as the studied attacks are often very idiosyncratic. In this paper, we explore the rally around the flag effect in an arguably difficult context: a sustained terrorist campaign held by domestic terrorist groups in a parliamentary democracy (Spain). To overcome the limitations of the single-attack studies, we use a multiple unexpected event approach: we developed a systematic process of matching the occurrence of terror attacks during the fieldwork of official public opinion surveys in Spain, through which we identified 142 valid attack-survey pairs. We find that in the attacked region support for the incumbent increases, on average, around 4 percentage points right after an attack, while support for the opposition decreases in a similar amount. These effects seem to occur mostly for the conservative incumbent and are especially relevant for the attacks that target civilians. We use a survey experiment to provide additional evidence in support for our interpretation of the findings.

The end of Operation Barkhane in the Sahel in 2022 raises many questions about French foreign policy in Africa. Yet the government has stifled public debate by insisting on the urgency of other wars in the world. As for the Members of Parliament, they never demanded an inquiry into the setbacks of France’s biggest overseas military operation since the Algerian war. Clearly, lessons were not learned. This article reviews the arguments and the political, military, historical and cultural reasons that led the Elysée to conceal, or even deny, a failure that also resulted in a loss of influence in its Francophone ‘preserve’ and among European Union partners who had overestimated the former colonial power’s ability to solve crises south of the Sahara. Blaming others, conspiracy theories and complaints about a lack of resources or the restrictions of international mandates to fight a global war on terror’ were part of the rhetorical weapons used to counter criticism, while some claimed that the end of Operation Barkhane was only a political defeat but not a military one.

Deprivation of national citizenship is one of the strategies used to counter the phenomenon of foreign terrorist fighters, that is, individuals traveling abroad for the purpose of terrorism. This Article begins with a short overview of the case-law of the European Court of Human Rights on the deprivation of citizenship. In these cases, the contestation of the deprivation of citizenship was based on the infringement of the rights to private and family life. We then turn to the limits imposed by EU law on decisions made by national authorities of Member States concerning citizenship deprivation of foreign terrorist fighters. Focusing on recent cases of the Court of Justice of the European Union (CJEU) concerning the European citizenship, we address the evolving role that EU law plays in the assessment of the proportionality of Member States’ decisions to strip individuals of national citizenship. We also consider the national practice, focusing on a recent decision in Denmark. In addition, we consider legal issues arising from the repatriation of Foreign Terrorist Fighters and their children. We argue that EU citizenship thus offers a further layer of protection against the deprivation of citizenship and that Member States are under a positive obligation to repatriate EU citizens who are the children of Foreign Terrorist Fighters on account of the case-law stemming from the Ruiz-Zambrano and X (Thai national) cases. For the moment, no common approach to repatriation of foreign fighters, or their children, is taken by EU member States in the context of the EU.

We introduce a dynamic game of outbidding where two groups use violence to compete in a tug-of-war fashion for evolving public support. We fit the model to the canonical outbidding rivalry between Hamas and Fatah using newly collected data on Palestinian public support for these groups. Competition has heterogeneous effects, and we demonstrate that intergroup competition can discourage violence. Competition from Hamas leads Fatah to use more terrorism than it would in a world where Hamas abstains from terrorism, but competition from Fatah can lead Hamas to attack less than it otherwise would. Likewise, making Hamas more capable or interested in competing increases overall violence, but making Fatah more capable or interested discourages violence on both sides. These discouragement effects of competition on violence emerge through an asymmetric contest, in which we find that Fatah uses terrorism more effectively to boost its support, although Hamas has lower attack costs. Expanding on these results, we demonstrate that outbidding theory is consistent with a positive, negative, or null relationship between measures of violence and incentives to compete.