I work as assistant professor at University of Twente, senior researcher at Fund Victim Support, and guest researcher at University of Groningen, Utrecht University (NL), Aarhus University (DK) and University of New South Wales (AUS). My research is focused on the definition, assessment, prediction, and treatment of disturbed grief in bereaved adults and children.  

In projects among people who experienced losses because of a long-term disappearance, homicide, MH17 plane disaster, traffic accident, COVID-19, and Russian war in Ukraine I examine risk factors and treatment of distress. I have authored more than 80 peer-reviewed journal articles. According to a bibliometric study from 2023 on the most productive/influential authors on the topic of prolonged grief disorder (https://doi.org/10.1080/07481187.2023.2196734) I am the third most productive academic in the world.

As main applicant/principal investigator, I received funding (> 870.000 euros) for ten research projects, including a NWO Veni-grant in 2022. As co-applicant, I received funding (>250.000 euros) for four research projects. Funding agencies that financially supported my work are Fund Victim Support, Dutch Ministry of Justice and Safety, NWO, SASS, Stichting Catharine van Tussenbroek, and Utrecht and Twente University Fund.

Additional roles:
1. Editor for special issue on grief in Frontiers in Psychiatry (https://www.frontiersin.org/research-topics/23195/consequences-and-aftercare-of-a-traumatic-loss-of-a-loved-one) (2021-2023)
2. Ad-hoc reviewer for several academic journals (see for overview: https://www.webofscience.com/wos/author/record/155722)
3. Former board member of the Dutch Society for Psychotrauma (see www.ntvp.nl). This is a society for therapists and researchers working with psychotrauma. It consists of 600+ members and ~14.000 LinkedIn followers. (2019-2023)
4. Chair Special Interest Group Traumatic Grief of the Dutch Society for Psychotrauma (2023-current)
5. Finance/Research officer Bereavement Network Europe (community that connects European professionals working with bereaved people) (2020-current)
6. Teacher in research practice at PPO (a post-master education for clinical psychologists) (2019-current)
7. Editorial board of Impact Magazine (https://oorlog.arq.org/nl/impact-magazine-0) (2021-current)
8. Review committee member Dutch Veterans Institute (Nederlands Veteranen Instituut) (2022)

Co-promotor/Principal investigator/Daily supervisor
PhD Candidate Iris van Dijk (2020-2024)
PhD Candidate Lyanne Reitsma (2020-2024)
PhD Candidate Lieke Nijborg (2022-2025)

PhD Candidate Deniz Ergun (2023-2027)


PhD Committee member
PhD Sander Vos (2021)


  • Psychology

    • Grief
    • Depression
    • Posttraumatic Stress Disorder
    • Treatment
    • Research
    • Self-Report
    • Systematic Literature Review
    • Cognitive Behavioral Therapy



A longitudinal study of risk and protective factors for symptoms of adjustment disorder during the COVID-19 pandemicEuropean Journal of psychotraumatology, 15(1), Article 2318944 (E-pub ahead of print/First online). Lotzin, A., Stahlmann, K., Acquarini, E., Ajdukovic, D., Ajdukovic, M., Anastassiou-Hadjicharalambous, X., Ardino, V., Bondjers, K., Bragesjö, M., Böttche, M., Dragan, M., Figueiredo-Braga, M., Gelezelyte, O., Grajewski, P., Javakhishvili, J. D., Kazlauskas, E., Lenferink, L., Lioupi, C., Lueger-Schuster, B., … Schäfer, I.https://doi.org/10.1080/20008066.2024.2318944Treatment Gap in Mental Health Care for Victims of Road Traffic AccidentsClinical Psychology and Psychotherapy, 31(2), Article e2970. Boelen, P., Eisma, M., de Keijser, J. & Lenferink, L. M.https://doi.org/10.1002/cpp.2970Grief and delivering a statement in court: a longitudinal mixed-method study among homicidally bereaved peopleEuropean Journal of psychotraumatology, 15(1), Article 2297541, 1-14. Nijborg, L., Kunst, M. J. J., Westerhof, G. J., de Keijser, J. & Lenferink, L.https://doi.org/10.1080/20008066.2023.2297541
Latent classes of prolonged grief and other indicators of mental health in bereaved adults: A systematic reviewJournal of Affective Disorders Reports, 14, Article 100654. Heeke, C., Franzen, M., Knaevelsrud, C. & Lenferink, L.https://doi.org/10.1016/j.jadr.2023.100654The disappearance of a loved one: Consequences and care. Lenferink, L.Latent trajectories of DSM-5-TR-based Prolonged Grief Disorder: findings from a data pooling project MARBLESEuropean Journal of psychotraumatology, 14(2), Article 2281183. Pociunaite, J., van Dijk, I., Reitsma, L., Leonard Nordström, E. E., Boelen, P. A. & Lenferink, L.https://doi.org/10.1080/20008066.2023.2281183Assessing DSM-5-TR and ICD-11 Prolonged Grief Disorder in children and adolescents: Development of the Traumatic Grief Inventory – Kids – Clinician Administered European Journal of psychotraumatology, 14(2), Article 2197697. van Dijk, I., Boelen, P. A., de Keijser, J. & Lenferink, L.https://doi.org/10.1080/20008066.2023.2197697Data sharing and re-use in the traumatic stress field: An international survey of trauma researchersEuropean Journal of psychotraumatology, 14(2), Article 2254118. Prakash, K., Kassam-Adams, N., Lenferink, L. & Greene, T.https://doi.org/10.1080/20008066.2023.2254118Grief is a family affair: Examining longitudinal associations between prolonged grief in parents and their adult children using four-wave cross-lagged panel modelsPsychological medicine, 53(15), 7428-7434. Lenferink, L. & O'Connor, M.https://doi.org/10.1017/S0033291723001101Behoeften, gebruik en effectiviteit van rouwzorg na een overlijden van een dierbare door een verkeersongeval. Lenferink, L.Psychometric evaluation of the Swedish Traumatic Grief Inventory Self-Report Plus (TGI-SR+) in bereaved parentsClinical Psychology and Psychotherapy. Lenferink, L. I. M., van Dijk, I., Eisma, M. C., Eklund, R., Boelen, P. A. & Sveen, J.https://doi.org/10.1002/cpp.2922Rampen, aanslagen en pandemieënIn Handboek Traumatische Rouw (pp. 123-136). Uitgeverij Boom. de Keijser, J., Lenferink, L., Reitsma, L. & Smid, G. E.VermissingIn Handboek Traumatische Rouw (pp. 137-149). Uitgeverij Boom. Lenferink, L., de Keijser, J. & Boelen, P. A.Is it acceptable and feasible to measure prolonged grief disorder symptoms in daily life using experience sampling methodology?. Lenferink, L.Predictors of traumatic experiences among individuals experiencing pandemic-related stressors: a cross-sectional study in Europe during the COVID-19 crisisCurrent Psychology (E-pub ahead of print/First online). Lioupi, C., Anastassiou-Hadjicharalambous, X., Acquarini, E., Ajdukovic, D., Ardino, V., Böttche, M., Dragan, M., Figueiredo-Braga, M., Gelezelyte, O., Grajewski, P., Javakhishvili, J. D., Kazlauskas, E., Lenferink, L., Lueger-Schuster, B., Tsiskarishvili, L., Mooren, T., Sales, L., Ajdukovic, M., Zrnic Novakovic, I., … Lotzin, A.https://doi.org/10.1007/s12144-023-05036-8The Traumatic Grief Inventory-Clinician Administered: A psychometric evaluation of a new interview for ICD-11 and DSM-5-TR prolonged grief disorder severity and probable casenessJournal of Affective Disorders, 330, 188-197. Lenferink, L., Franzen, M., ten Klooster, P. M., Knaevelsrud, C., Boelen, P. A. & Heeke, C.https://doi.org/10.1016/j.jad.2023.03.006Grief is a family affair: examining longitudinal associations between prolonged grief in parents and their adult children using four-wave cross-lagged panel models. Lenferink, L.Latent trajectories of DSM-5-TR based Prolonged Grief Disorder: Findings from a data pooling project MARBLES. Lenferink, L.Is it acceptable and feasible to measure prolonged grief disorder symptoms in daily life using experience sampling methodology?. Lenferink, L.Opportunities for improving data sharing and FAIR data practices to advance global mental healthGlobal Mental Health, 10, Article e14. Sadeh, Y., Denejkina, A., Karyotaki, E., Lenferink, L. I. M. & Kassam-Adams, N.https://doi.org/10.1017/gmh.2023.7Self-guided online treatment of disturbed grief, posttraumatic stress, and depression in adults bereaved during the COVID-19 pandemic: A randomized controlled trialBehaviour research and therapy, 163, Article 104286. Reitsma, L., Boelen, P. A., de Keijser, J. & Lenferink, L.https://doi.org/10.1016/j.brat.2023.104286DSM-5-TR prolonged grief disorder levels after natural, COVID-19, and unnatural loss during the COVID-19 pandemicJournal of Affective Disorders Reports, 12, Article 100516. Lenferink, L. & Boelen, P. A.https://doi.org/10.1016/j.jadr.2023.100516Co-occurrence of approach and avoidance in prolonged grief: a latent class analysisEuropean Journal of psychotraumatology, 14(2), Article 2190544. Eisma, M. C. & Lenferink, L.https://doi.org/10.1080/20008066.2023.2190544The Ambiguous Loss Inventory Plus (ALI+): Introduction of a measure of psychological reactions to the disappearance of a loved oneInternational journal of environmental research and public health, 20(6), Article 5117. Comtesse, H., Killikelly, C., Hengst, S. M. C., Lenferink, L. I. M., de la Rie, S. M., Boelen, P. A. & Smid, G. E.https://doi.org/10.3390/ijerph20065117Prevalence and correlates of positive and negative psychological effects of bereavement due to COVID-19: A living systematic review [version 1; peer review: awaiting peer review]F1000Research, 12, Article 237 (E-pub ahead of print/First online). Reitsma, L., Killikelly, C., Müller, H., Larsen, L., Boelen, P. & Lenferink, L.https://doi.org/10.12688/f1000research.130397.1

Research profiles

Affiliated study programs

Courses academic year 2023/2024

Courses in the current academic year are added at the moment they are finalised in the Osiris system. Therefore it is possible that the list is not yet complete for the whole academic year.

Courses academic year 2022/2023

Current projects

The TALE study

TGI-CA Assessment after Loss in Europe

The primary aim of the TALE-study is to evaluate the psychometric properties of the Traumatic Grief Inventory - Clinical Administered (TGI-CA). The TGI-CA is an interview that is developed to assess pathological grief criteria (proposed for inclusion) in DSM-5 and ICD-11. During this study data will be collected among Dutch and German-speaking bereaved people by telephone interviews. Collaborators: drs. Minita Franzen (University of Groningen), dr. Carina Heeke (Freie Universität Berlin) en prof. dr. Paul A. Boelen (Utrecht University and Arq National Psychotrauma Centre).

Grief after the MH17 plane disaster

Aim: to examine the course of symptoms over time in people who lost one or multiple significant others due to the plane disaster with flight MH17. Among others latent class growth modeling and cross-lagged panel analyses are used to analyze the data. Furthermore, the effectiveness of a treatment for this group will be evaluated in a randomized controlled trial. Collaborators: prof. dr. Jos de Keijser (University of Groningen), prof. dr. Paul A. Boelen (Utrecht University and Arq National Psychotrauma Centre), prof. dr. Geert E. Smid (Centre '45 and Arq National Psychotrauma Centre), and dr. Angela Nickerson (University of New South Wales, Australia).

Treatment of disturbed grief after the death of a loved one during the COVID-19 pandemic

Grief during the pandemic

This PhD-project consists of two trials: 1) In a randomized controlled trial the effects of an online unguided grief-specific cognitive behavioral therapy (vs. waitlist controls) will be evaluated in people who lost a loved one during the pandemic. 2) In a controlled trial the effects of an online guided grief-specific cognitive behavioral therapy (vs. online unguided grief-specific cognitive behavioral therapy) will be evaluated in people who lost a loved one during the pandemic. Research team: Lyanne Reitsma (PhD candidate) Lonneke Lenferink (Principal Investigator/main applicant) Paul Boelen and Jos de Keijser (co-applicants)

CONNECT project


The aim of this project is to examine the course and determinants of psychotrauma complaints related to the COVID-19 pandemic in the general Dutch population. This is a longitudinal survey study among over 2000 Dutch people. This project is part of a pan-European study on the positive and negative consequences of the COVID-19 pandemic executed in eleven European countries. Collaborators: European Society for Traumatic Stress Studies (ESTSS), Nederlandstalige Vereniging voor Psychotrauma (NtVP), prof. dr. Trudy Mooren (Utrecht University, Centre '45), drs. Suzan Soydas (Utrecht University), dr. Joanne Mouthaan (Leiden University), drs Marloes Eidhof (Radboud University, Reinier van Arkel), dr. Marie-José van Hoof (Leiden University) en dr. Simon Groen (GGZ Drenthe)

The Aarhus Bereavement Study


The Aarhus Bereavement Study (TABstudy) is an ongoing multi-wave, registry-based cohort study, examining grief reactions in bereaved adults led by associate prof. Maja O'Connor at Aarhus University (Denmark). Aarhus University granted a research visit in fall 2022 so I could collaborate on this project by analyzing data among bereaved families using structural equation modelling.


Aim: to identify risk factor for developing psychological complaints among people who lost a significant other due to a traffic accident. In addition, the effectiveness of an online treatment for reducing psychopathology levels will be evaluated. Collaborators: prof. dr. Jos de Keijser (University of Groningen), prof. dr. Paul A. Boelen (Utrecht University and Arq National Psychotrauma Centre), prof. dr. Geert E. Smid (Centre '45 and Arq National Psychotrauma Centre), and dr. Maarten Eisma (University of Groningen)

The therapeutic effects of "GriefHelp"

Aim: to evaluate the effectiviness of a psychological intervention for reducing prolonged grief symptoms in minors who lost a significant other. Collaborators: prof. dr. Paul A. Boelen (Utrecht University and Arq National Psychotrauma Centre) and dr. Mariken Spuij (Utrecht University)

Measurements Archive of Reactions to Bereavement from Longitudinal European Studies (MARBLES) project

Aim: to develop an international data-archive for secundary analyses on Findable, Accessible, Interoperable and Reusable (FAIR) longitudinal (non-intervention) grief data in adults. Collaborators: prof. dr. Paul A Boelen (Utrecht University and ARQ national psychotrauma centre) and Nancy Kassam-Adams (Children’s Hospital of Philadelphia and the University of Pennsylvania Perelman School of Medicine, Philadelphia, USA)

Toward personalized bereavement care: Examining individual differences in response to grief treatment

Prolonged grief disorder is a debilitating condition, affecting 10% of bereaved people. To date, studies evaluating treatments for prolonged grief have focused on symptom change on a group-level, ignoring individual variability in grief-responses. Personalized prolonged grief treatment may enhance treatment outcomes. This project contributes in three ways to personalized treatment for prolonged grief, by: (i) improving the understanding of differences in grief-trajectories in response to treatment for prolonged grief using a novel FAIR data-archive; (ii) examining grief in daily life; (iii) offering dynamic support in daily life to treat prolonged grief. 2022-2026 Veni-grant NWO

TrafVic Kids

The aims of this PhD-project (2020-2024) are to: 1) develop and validate a clinical interview to assess prolonged grief disorder (PGD) symptoms in children and 2) to develop and evaluate a online treatment for PGD in children bereaved by a traffic accident. PhD-student is Iris van Dijk Promotores: prof. dr. Paul Boelen and prof. dr. Jos de Keijser Co-promotores and daily supervisor: dr. Lonneke Lenferink

Finished projects

In the press

Media outlet highlights
Original title [English title]
Date (day/month/year)

  1. Interview Dutch national newspaper Algemeen Dagblad
    Zoektocht naar vermiste Samuël gestaakt: ‘We moeten nu accepteren dat hij niet gevonden wordt’ [The search for Samuël discontinued: ‘We now need to accept that he will not be found’]
  2. Interview professional Dutch magazine Vakblad Uitvaart
    Grotere kans op rouwstoornis door corona [Increased risk of a grief disorder due to corona]
  3. Interview Dutch national newspaper Algemeen Dagblad
    Hoe rouw je in tijden van corona? [How to grieve in times of COVID?]
  4. Blog Nederlandstalige Vereniging voor Psychotrauma
    Yalom: “Get in therapy; go through your own issues!”
  5. Interview Dutch national radio Radio1
    Radio 1: Online rouwen tijdens pandemie [Grieving online during pandemic]
  6. Dutch national t.v. Nieuwsuur
    Hoe is het om door corona nooit echt afscheid te kunnen nemen van je geliefde [What is it like to never really say goodbye to your loved one because of corona?]
  7. Online Dutch article published by Fund Victim Support
    Afscheid en rouw in tijden van corona [Farewell and grief in COVID-19 times]
  8. Live-interview Dutch national radio Radio1
    Impact op achterblijvers van vermiste is enorm [impact on those left behind after a disappearance is huge]
  9. Interview Dutch national newspaper Algemeen Dagblad
    Hierdoor maakt de vermissing van Dirk Dalebout meer los dan andere zaken [This is why the disappearance of Dirk Dalebout results in relatively more reactions than other cases]
  10. Interview Dutch national newspaper Algemeen Dagblad
    Bijna 300 vermiste Nederlanders: het kan ook jou overkomen [Nearly 300 missing Dutch people: it could also happen to you
  11. Interview Dutch national newspaper Volkskrant Magazine
    "Ik zou zo graag willen horen uw kind is dood" [“I would like to hear your child is dead”]
  12. Interview Dutch professional magazine "de Psycholoog"
    Tussen hoop en vrees [In limbo]
  13. Interview Dutch national newspaper NRC Handelsblad
    "Hardnekkige rouw om een vermiste" [Disturbing grief after someone is missing]
  14. Online interview for Dutch national news NOS
    Mensen die hoop houden na de vermissing van een dierbare hebben de meeste klachten [People who maintain hope after the disappearance of loved one have the highest distress]
  15. Interview regional Dutch newspaper “de Stentor”
    Achterblijvers van vermisten in therapie [Relatives of missing people in treatment]
  16. Live regional Dutch television interview Omroep Brabant
    88 Brabanders langdurig vermist [88 people from the region Brabant are long-term missing]


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