What influence did the internal debates on the use of violence within left-wing activist movements, and the government’s response to this (political) violence, have on the development, level, and continuity of the violence originating from these movements in the period 1965–2015?

Can behaviour in an online economic game be understood as a representation of radicalisation propensity?

This study is a critical discourse analysis of the misogynistic narratives shared by three incel violent extremists.

Just a few years ago, jihadist terrorism was seen as Europe’s most pressing threat. Today, we are facing hybrid warfare and extremist groups that are undermining our safety from within. Bart Schuurman, Professor of Terrorism and Political Violence, calls for a different kind of research.

Physical chemist Rik Mom developed a revolutionary way to investigate catalysts in action in detail. For this work he received the distinction cum laude during his PhD defence on 29 June.

A professor from Leiden University has subjected various colleagues to intimidating and unacceptable behaviour for a longer period. These are the findings of an investigation carried out by the University’s independent Complaints Committee for Unacceptable Behaviour at the request of the Executive Board…

The brain structure of young people with conduct disorder differs significantly from that of their typically developing peers. This is the conclusion of an international study that analysed more than two thousand MRI scans, recently published in The Lancet Psychiatry. Dr Moji Aghajani, one of the principal…

This research examines how right-wing extremist parents perceive and discuss their role in the ideological socialisation of their children.

When does radicalization not lead to terrorist attacks?

From 16 to 18 August, 30 participants from 18 different countries gathered online to participate in the Online Summer Programme: Preventing, Detecting and Responding to Violent Extremism, organised by Leiden University’s Centre for Professional Learning (CPL) together with the International Centre for…

What should policymakers and politicians do to prevent violent extremism? What are the greatest risks posed by the radical left and right? How do ideological media publications that terrorists assemble before attacks, may help to counter extremist narratives? About 30 professionals from all over the…

After a career spanning decades in intelligence services, Berrie Hanselman could have simply retired, but he chose not to. The Achterhoek native decided to continue and even earn a PhD on his subject: left-wing extremism. Gaining insight into the life of the left-wing activist who does not shy away…

Dutch troops, judges and politicians collectively condoned and concealed the systematic use of extreme violence during the Indonesian War of Independence. Historians have now shown how this could happen. ‘It was scandal management rather than prevention,’ says Leiden historian and research leader Gert…

Roughly arrested and subjected to extreme isolation. Using his experience, expert Jason Bhugwandass spoke to 50 young people who have spent time on Zikos wards (‘very intense, short-term observation and stabilisation wards’). He concluded that they’re ‘mostly locked up’ and leave ‘even more traumatised’…

Joseph Callingham from the Leiden Observatory receives the Louise Webster Prize for outstanding post-doctoral research. The prize is awarded by the Astronomical Society of Australia for Callingham’s search for the most extreme object in the Universe.

What happens to children of extremist parents? Commissioned by the Scientific Research and Documentation Center (WODC) of the Ministry of Justice and Security, four ISGA researchers, Layla van Wieringen, Daan Weggemans, Katharina Krüsselmann and Marieke Liem, wrote a report on the nature and extent…

Edwin Bakker is one of the speakers during the

Symposium

The rise of extremism in Europe has increased polarisation. The EU-funded DRIVE project, led by Tahir Abbas, Professor of Radicalisation Studies from Leiden University’s Institute of Security and Global Affairs, explores how social, structural, and individual factors contribute to radicalisation, offering…

Going to school during the summer holidays? Some of our students accepted the challenge. And they didn’t do that just around the corner. During their holidays, students bio pharmaceutical sciences and computer science visited special summer schools in China. ‘China is a global player that we should…

It is in the interest of all democracies for young people to learn the value of free debate, even on sensitive and potentially divisive issues like terrorism, argue Thorbjørn Jagland (secretary general of the Council of Europe), Sayeeda Warsi (UK parliamentarian), and Francesco Ragazzi (Institute of…

Since 2012, thousands of individuals have traveled from Western countries to join jihadist groups in Syria and Iraq. While much has been written about these individuals, only sparse attention has been paid to the social environment of these jihadist travelers and, more specific, the role of family members…

Rianne Scheerhoorn is a government trainee at the Ministry of Economic Affairs and Climate Policy and the Ministry of Agriculture, Nature and Food Quality. After completing her Bachelor's and Master's degrees in Public Administration, she was sure that the Central Government Traineeship Programme (Rijkstraineesprogramma)…

Alastair Reed, Assistant professor at the Institute of Security and Global Affairs (ISGA) is interviewed by Devex, the media platform for the global development community.

Dr. Mark Dechesne, associate professor at the Leiden University Dual PhD Centre (FGGA) will participate asas work package leader in a large new international project on radicalization among young people in Europe.

Over 300 people from 38 different countries took part in the online lecture

How to minimalize the chance of recidivism for extremist prisoners.

Marieke Liem, Associate Professor, at the Institute of Security and Global Affairs, was interviewed by RTL Nieuws on Tuesday morning 27 August about the increase in violence with illegal hand grenades in the Netherlands.

The UK has recently been facing racist violence outbreaks. Tahir Abbas, Professor of Radicalisation Studies, discusses this in an article on Hyphen.

On Tuesday 30 September 2025, PhD candidate Jonathan Collins will defend his dissertation A Wolf in Sheep’s Clothing: A Mixed-Methods Analysis of the Far-Right Alt-Tech Social Media Movement in Leiden’s Academy Building. His work examines the communication dynamics of far-right communities on alternative…

Course, Training

Nikki Sterkenburg, external PhD candidate at the Institute of Security and Global Affairs in The Hague, was interviewed by the NOS programme Nieuws & Co about the meeting of Thierry Baudet with Alt-Right movement Jared Taylor. 'If Baudet would have wished to stay aloof of this movement, he shouldn’t…

The METIS instrument that’s being built for ESO's future Extremely Large Telescope (ELT) in Northern Chile under the leadership of the Dutch Research School for Astronomy (NOVA) has reached an important milestone: the preliminary design has been approved.

PhD defence

Leiden scientists will be working on the development of a camera for the European Extremely Large Telescope that is currently under construction. On 28 September the Netherlands Research School for Astronomy signed an agreement with the European Southern Observatory.

To what extent does exoplanet Proxima b resemble our Earth? And is there some form of life present? Astronomers hope to find answers to these questions with the new European Extremely Large Telescope (ELT). An NWO research grant of €18 million will allow a Dutch consortium to continue building instruments…

Conference

Understanding the evolving landscape of extremism in the 21st century.

Jeanine de Roy van Zuijdewijn, researcher and lecturer at ISGA, was a guest on NPO Radio 1 where she discussed the attacks carried out in 2011 by Anders Breivik.

PhD defence

The funerary textile tradition from the Osmore Valley, South Peru, and its social-political implications (2005)

After this course, you will

The Terrorism and Political Violence (TPV) research group focuses on understanding and addressing one of today’s most pressing security challenges: terrorism. Drawing from their academic expertise, the group offers a wide range of educational programmes designed for students, professionals, and a global…