{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:38:03Z","timestamp":1785418683001,"version":"3.56.0"},"reference-count":48,"publisher":"Cambridge University Press (CUP)","license":[{"start":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T00:00:00Z","timestamp":1780531200000},"content-version":"unspecified","delay-in-days":154,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Psychol. Med."],"published-print":{"date-parts":[[2026]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec id=\"S0033291726104048_sec32\">\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>The COVID-19 pandemic exposed individuals to numerous psychosocial and health-related stressors associated with adjustment disorder (AjD) symptoms, yet it remains unclear which factors are most predictive.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"S0033291726104048_sec33\" sec-type=\"methods\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Using mixed-effects regression random forests (MERF), a machine learning approach that combines random forests with mixed-effects regressions, we analyzed longitudinal data from 15,155 adults across 11 European countries collected at three time points between June 2020 and January 2022. We evaluated 245 candidate predictors, including sociodemographic, pandemic-related, and health-related factors, for their relative importance in predicting AjD symptoms (ADNM-8).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"S0033291726104048_sec34\" sec-type=\"results\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The seven most influential predictors, ranked in descending order of importance, were uncertainty about the pandemic\u2019s duration and risks, poor health, social isolation, conflicts at home, loss of daily structure, fear of infection, and restricted personal contact with close others.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"S0033291726104048_sec35\" sec-type=\"conclusions\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>AjD symptoms were most strongly linked to factors related to lack of control (e.g., uncertainty, loss of daily structure, fear of infection), as well as current poor health and reduced social connectedness. Interventions that enhance a sense of control through clear communication, help individuals re-establish daily routines, and strengthen social connectedness may mitigate AjD symptoms during future public health crises. Our findings also highlight the potential of machine learning approaches for identifying complex patterns across high-dimensional predictors of clinical symptoms, which may improve prediction accuracy in mental health research.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1017\/s0033291726104048","type":"journal-article","created":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T06:36:04Z","timestamp":1780554964000},"update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":0,"title":["Determining the relative importance of risk and protective factors for adjustment disorder symptoms during the COVID-19 pandemic by mixed-effects random forests"],"prefix":"10.1017","volume":"56","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2834-8047","authenticated-orcid":false,"given":"Annett","family":"Lotzin","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01zgy1s35","id-type":"ROR","asserted-by":"publisher"}],"name":"University Medical Center Hamburg-Eppendorf"},{"id":[{"id":"https:\/\/ror.org\/006thab72","id-type":"ROR","asserted-by":"publisher"}],"name":"MSH Medical School Hamburg"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6736-0022","authenticated-orcid":false,"given":"Emily","family":"Finne","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/006thab72","id-type":"ROR","asserted-by":"publisher"}],"name":"MSH Medical School Hamburg"},{"id":[{"id":"https:\/\/ror.org\/00t3r8h32","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Luebeck"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Georg","family":"Schildbach","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00t3r8h32","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Luebeck"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elena","family":"Acquarini","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04q4kt073","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Urbino"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dean","family":"Ajdukovic","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00mv6sv71","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Zagreb"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marina","family":"Ajdukovic","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00mv6sv71","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Zagreb"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xenia","family":"Anastassiou-Hadjicharalambous","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04v18t651","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Nicosia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vittoria","family":"Ardino","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04q4kt073","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Urbino"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6206-6780","authenticated-orcid":false,"given":"Ida","family":"Hensler","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/056d84691","id-type":"ROR","asserted-by":"publisher"}],"name":"Karolinska Institutet"},{"id":[{"id":"https:\/\/ror.org\/048a87296","id-type":"ROR","asserted-by":"publisher"}],"name":"Uppsala University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1317-2093","authenticated-orcid":false,"given":"Filip K.","family":"Arnberg","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/048a87296","id-type":"ROR","asserted-by":"publisher"}],"name":"Uppsala University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"B\u00f6ttche","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/046ak2485","id-type":"ROR","asserted-by":"publisher"}],"name":"Freie Universit\u00e4t Berlin"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8221-2012","authenticated-orcid":false,"given":"Ma\u0142gorzata","family":"Dragan","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/039bjqg32","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Warsaw"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Margarida","family":"Figueiredo-Braga","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/043pwc612","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Porto"},{"id":[{"id":"https:\/\/ror.org\/04z8k9a98","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Coimbra"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8501-3502","authenticated-orcid":false,"given":"Odeta","family":"Gelezelyte","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03nadee84","id-type":"ROR","asserted-by":"publisher"}],"name":"Vilnius University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6673-0562","authenticated-orcid":false,"given":"Piotr","family":"Grajewski","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/039bjqg32","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Warsaw"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6509-5969","authenticated-orcid":false,"given":"Simon","family":"Groen","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0107rkg57","id-type":"ROR","asserted-by":"publisher"}],"name":"Centre for Transcultural Psychiatry"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marie-Jos\u00e9","family":"van Hoof","sequence":"additional","affiliation":[{"name":"iMindU GGZ"},{"id":[{"id":"https:\/\/ror.org\/05grdyy37","id-type":"ROR","asserted-by":"publisher"}],"name":"Amsterdam UMC"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jana Darejan","family":"Javakhishvili","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/051qn8h41","id-type":"ROR","asserted-by":"publisher"}],"name":"Ilia State University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6654-6220","authenticated-orcid":false,"given":"Evaldas","family":"Kazlauskas","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03nadee84","id-type":"ROR","asserted-by":"publisher"}],"name":"Vilnius University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8649-5777","authenticated-orcid":false,"given":"Chrysanthi","family":"Lioupi","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04v18t651","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Nicosia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brigitte","family":"Lueger-Schuster","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03prydq77","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Vienna"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luisa","family":"Sales","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04z8k9a98","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Coimbra"},{"name":"Hospital Militar"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lela","family":"Tsiskarishvili","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/051qn8h41","id-type":"ROR","asserted-by":"publisher"}],"name":"Ilia State University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irina","family":"Zrnic Novakovic","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03prydq77","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Vienna"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ingo","family":"Sch\u00e4fer","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01zgy1s35","id-type":"ROR","asserted-by":"publisher"}],"name":"University Medical Center Hamburg-Eppendorf"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"name":"ADJUST Study Consortium","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2026,6,4]]},"reference":[{"key":"S0033291726104048_r1","doi-asserted-by":"publisher","DOI":"10.18637\/jss.v067.i01"},{"key":"S0033291726104048_r26","volume-title":"The psychobiology of depression","author":"Lewinsohn","year":"1974"},{"key":"S0033291726104048_r3","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychires.2018.05.011"},{"key":"S0033291726104048_r8","doi-asserted-by":"publisher","DOI":"10.1037\/0033-2909.98.2.310"},{"key":"S0033291726104048_r25","volume-title":"Stress, appraisal, and coping","author":"Lazarus","year":"1984"},{"key":"S0033291726104048_r27","doi-asserted-by":"publisher","DOI":"10.1007\/s10826-025-03062-7"},{"key":"S0033291726104048_r4","doi-asserted-by":"publisher","DOI":"10.1023\/A:1010933404324"},{"key":"S0033291726104048_r33","doi-asserted-by":"publisher","DOI":"10.1002\/wps.20057"},{"key":"S0033291726104048_r39","volume-title":"R: A language and environment for statistical computing","year":"2023"},{"key":"S0033291726104048_r40","unstructured":"Roser, M. (2021). What is the COVID-19 stringency index? Our World in data. https:\/\/ourworldindata.org\/metrics-explained-covid19-stringency-index"},{"key":"S0033291726104048_r48","doi-asserted-by":"publisher","DOI":"10.1080\/20008198.2019.1708617"},{"key":"S0033291726104048_r46","unstructured":"Weathers, F. W. , Keane, T. M. , Palmieri, P. A. , Marx, B. P. , & Schnurr, P. P. (2013). PTSD checklist for DSM-5 (PCL-5) with Criterion A. https:\/\/www.ptsd.va.gov\/professional\/assess-ment\/adult-sr\/ptsd-checklist.asp"},{"key":"S0033291726104048_r5","doi-asserted-by":"publisher","DOI":"10.1037\/0022-006X.68.5.748"},{"key":"S0033291726104048_r17","doi-asserted-by":"publisher","DOI":"10.1037\/0003-066X.44.3.513"},{"key":"S0033291726104048_r10","doi-asserted-by":"publisher","DOI":"10.1016\/S0749-3797(98)00017-8"},{"key":"S0033291726104048_r22","unstructured":"Kronziel, L. L. & Laabs, B. (2025). timbR: Tree interpretation methods based on ranger (Version 3.0) [Computer software]. https:\/\/github.com\/imbs-hl\/timbR"},{"key":"S0033291726104048_r23","doi-asserted-by":"publisher","DOI":"10.18637\/jss.v036.i11"},{"key":"S0033291726104048_r16","doi-asserted-by":"publisher","DOI":"10.1016\/j.jad.2021.06.080"},{"key":"S0033291726104048_r19","doi-asserted-by":"publisher","DOI":"10.1159\/000484415"},{"key":"S0033291726104048_r20","doi-asserted-by":"publisher","DOI":"10.1080\/20008198.2017.1421819"},{"key":"S0033291726104048_r12","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-030-56485-8"},{"key":"S0033291726104048_r24","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-031-63797-1_15"},{"key":"S0033291726104048_r18","doi-asserted-by":"publisher","DOI":"10.1093\/bib\/bbad002"},{"key":"S0033291726104048_r30","doi-asserted-by":"publisher","DOI":"10.1080\/20008198.2021.1964197"},{"key":"S0033291726104048_r35","unstructured":"Mayer, M. (2024). missRanger: Fast Imputation of Missing Values. R Package Version 2.6.1. https:\/\/CRAN.R-project.org\/package=missRanger"},{"key":"S0033291726104048_r36","doi-asserted-by":"publisher","DOI":"10.21105\/joss.00786"},{"key":"S0033291726104048_r43","first-page":"112","article-title":"MissForest\u2014Non-parametric missing value imputation for mixed-type data","volume":"28","author":"Stekhoven","year":"2012","journal-title":"Bioinformatics (Oxford, England)"},{"key":"S0033291726104048_r34","doi-asserted-by":"publisher","DOI":"10.1037\/rev0000033"},{"key":"S0033291726104048_r44","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2105-8-25"},{"key":"S0033291726104048_r47","unstructured":"WHO. (2021). ICD-11\u2014Mortality and morbidity statistics (Version: 05\/2021). ICD-11 - Mortality and Morbidity Statistics. https:\/\/icd.who.int\/browse11\/l-m\/en#\/http%3a%2f%2fid.who.int%2ficd%2fentity%2f991786158"},{"key":"S0033291726104048_r29","doi-asserted-by":"publisher","DOI":"10.1186\/s40359-022-00790-z"},{"key":"S0033291726104048_r38","first-page":"e1301","article-title":"Hyperparameters and tuning strategies for random forest","volume":"9","author":"Probst","year":"2019","journal-title":"Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery"},{"key":"S0033291726104048_r2","doi-asserted-by":"publisher","DOI":"10.1192\/bjo.2020.158"},{"key":"S0033291726104048_r42","volume-title":"A conceptual framework for action on the social determinants of health","author":"Solar","year":"2010"},{"key":"S0033291726104048_r15","doi-asserted-by":"publisher","DOI":"10.1080\/00949655.2012.741599"},{"key":"S0033291726104048_r7","doi-asserted-by":"publisher","DOI":"10.1016\/j.janxdis.2016.03.011"},{"key":"S0033291726104048_r41","doi-asserted-by":"publisher","DOI":"10.3389\/fpsyt.2020.00790"},{"key":"S0033291726104048_r45","doi-asserted-by":"publisher","DOI":"10.3389\/fpsyt.2018.00169"},{"key":"S0033291726104048_r9","doi-asserted-by":"publisher","DOI":"10.1080\/20008198.2020.1860356"},{"key":"S0033291726104048_r11","doi-asserted-by":"publisher","DOI":"10.1214\/07-AOAS148"},{"key":"S0033291726104048_r13","doi-asserted-by":"publisher","DOI":"10.1198\/tast.2009.08199"},{"key":"S0033291726104048_r21","unstructured":"Krennmair, P. , & Frink, N. (2023). SAEforest: Mixed effect random forests for small area estimation. R package (Version 1.0.1) [R package]. https:\/\/krennpa.github.io\/SAEforest"},{"key":"S0033291726104048_r37","doi-asserted-by":"publisher","DOI":"10.1016\/j.pneurobio.2017.05.004"},{"key":"S0033291726104048_r28","doi-asserted-by":"publisher","DOI":"10.1080\/20008198.2020.1780832"},{"key":"S0033291726104048_r32","doi-asserted-by":"publisher","DOI":"10.1080\/21642850.2022.2112198"},{"key":"S0033291726104048_r14","doi-asserted-by":"publisher","DOI":"10.1002\/wics.1346"},{"key":"S0033291726104048_r6","doi-asserted-by":"publisher","DOI":"10.1177\/0962280220946080"},{"key":"S0033291726104048_r31","doi-asserted-by":"publisher","DOI":"10.1080\/20008066.2024.2318944"}],"container-title":["Psychological Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0033291726104048","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T06:36:09Z","timestamp":1780554969000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0033291726104048\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026]]},"references-count":48,"alternative-id":["S0033291726104048"],"URL":"https:\/\/doi.org\/10.1017\/s0033291726104048","relation":{},"ISSN":["0033-2917","1469-8978"],"issn-type":[{"value":"0033-2917","type":"print"},{"value":"1469-8978","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026]]},"assertion":[{"value":"\u00a9 The Author(s), 2026. Published by Cambridge University Press","name":"copyright","label":"Copyright","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http:\/\/creativecommons.org\/licenses\/by\/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.","name":"license","label":"License","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This content has been made available to all.","name":"free","label":"Free to read"}],"article-number":"e181"}}