{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T20:46:16Z","timestamp":1786999576970,"version":"build-2736575974"},"reference-count":41,"publisher":"Cambridge University Press (CUP)","issue":"8","license":[{"start":{"date-parts":[[2017,1,23]],"date-time":"2017-01-23T00:00:00Z","timestamp":1485129600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Psychol. Med."],"published-print":{"date-parts":[[2017,6]]},"abstract":"<jats:sec id=\"S0033291716003615_sec_a1\">\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Chronic fatigue syndrome is likely to be a heterogeneous condition. Previous studies have empirically defined subgroups using combinations of clinical and biological variables. We aimed to explore the heterogeneity of chronic fatigue syndrome.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"S0033291716003615_sec_a2\" sec-type=\"methods\">\n                    <jats:title>Method<\/jats:title>\n                    <jats:p>We used baseline data from the PACE trial, which included 640 participants with chronic fatigue syndrome. Variable reduction, using a combination of clinical knowledge and principal component analyses, produced a final dataset of 26 variables for 541 patients. Latent class analysis was then used to empirically define subgroups.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"S0033291716003615_sec_a3\" sec-type=\"results\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The most statistically significant and clinically recognizable model comprised five subgroups. The largest, \u2018core\u2019 subgroup (33% of participants), had relatively low scores across all domains and good self-efficacy. A further three subgroups were defined by: the presence of mood disorders (21%); the presence of features of other functional somatic syndromes (such as fibromyalgia or irritable bowel syndrome) (21%); or by many symptoms \u2013 a group which combined features of both of the above (14%). The smallest \u2018avoidant\u2013inactive\u2019 subgroup was characterized by physical inactivity, belief that symptoms were entirely physical in nature, and fear that they indicated harm (11%). Differences in the severity of fatigue and disability provided some discriminative validation of the subgroups.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"S0033291716003615_sec_a4\" sec-type=\"conclusion\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>In addition to providing further evidence for the heterogeneity of chronic fatigue syndrome, the subgroups identified may aid future research into the important aetiological factors of specific subtypes of chronic fatigue syndrome and the development of more personalized treatment approaches.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1017\/s0033291716003615","type":"journal-article","created":{"date-parts":[[2017,1,23]],"date-time":"2017-01-23T05:53:34Z","timestamp":1485150814000},"page":"1454-1465","source":"Crossref","is-referenced-by-count":25,"title":["Heterogeneity in chronic fatigue syndrome \u2013 empirically defined subgroups from the PACE trial"],"prefix":"10.1017","volume":"47","author":[{"given":"T. E.","family":"Williams","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"T.","family":"Chalder","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M.","family":"Sharpe","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P. D.","family":"White","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2017,1,23]]},"reference":[{"key":"S0033291716003615_ref1","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-134-9_Part_2-200105011-00011"},{"key":"S0033291716003615_ref21","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychores.2015.10.004"},{"key":"S0033291716003615_ref4","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychores.2015.01.003"},{"key":"S0033291716003615_ref35","doi-asserted-by":"publisher","DOI":"10.1097\/00005650-199206000-00002"},{"key":"S0033291716003615_ref40","doi-asserted-by":"publisher","DOI":"10.1002\/art.1780330203"},{"key":"S0033291716003615_ref26","doi-asserted-by":"publisher","DOI":"10.1186\/1472-6963-3-25"},{"key":"S0033291716003615_ref18","doi-asserted-by":"publisher","DOI":"10.7326\/M15-0647"},{"key":"S0033291716003615_ref31","volume-title":"Report from the National Task Force on Chronic Fatigue Syndrome (CFS)\/Post Viral Fatigue Syndrome (PVMS)\/Myalgic Encephalomyelitis (ME)","year":"1994"},{"key":"S0033291716003615_ref25","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(06)68073-2"},{"key":"S0033291716003615_ref34","doi-asserted-by":"publisher","DOI":"10.1016\/j.cpr.2013.03.007"},{"key":"S0033291716003615_ref7","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychores.2011.02.009"},{"key":"S0033291716003615_ref12","doi-asserted-by":"publisher","DOI":"10.1007\/s001270050266"},{"key":"S0033291716003615_ref14","doi-asserted-by":"publisher","DOI":"10.1017\/S0033291700037417"},{"key":"S0033291716003615_ref16","doi-asserted-by":"publisher","DOI":"10.1016\/0895-4356(88)90138-2"},{"key":"S0033291716003615_ref22","doi-asserted-by":"publisher","DOI":"10.1192\/bjp.180.5.461"},{"key":"S0033291716003615_ref27","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(15)01223-4"},{"key":"S0033291716003615_ref20","first-page":"256","article-title":"Effect of a self-management program on patients with chronic disease","volume":"4","author":"Lorig","year":"2001","journal-title":"Effective Clinical Practice"},{"key":"S0033291716003615_ref11","doi-asserted-by":"publisher","DOI":"10.1136\/bmjopen-2013-002999"},{"key":"S0033291716003615_ref37","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(11)60096-2"},{"key":"S0033291716003615_ref3","doi-asserted-by":"publisher","DOI":"10.1186\/1478-7954-7-17"},{"key":"S0033291716003615_ref32","doi-asserted-by":"publisher","DOI":"10.1093\/sleep\/27.1.158"},{"key":"S0033291716003615_ref39","doi-asserted-by":"publisher","DOI":"10.1046\/j.1440-1614.2001.00888.x"},{"key":"S0033291716003615_ref17","doi-asserted-by":"publisher","DOI":"10.1017\/S0033291708003784"},{"key":"S0033291716003615_ref41","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0447.1983.tb09716.x"},{"key":"S0033291716003615_ref23","unstructured":"National Institute for Health and Clinical Excellence (2007). Chronic fatigue syndrome\/myalgic encephalomyelitis (or encephalopathy): diagnosis and management. Clinical guideline [CG53] (https:\/\/www.nice.org.uk\/Guidance\/cg53)."},{"key":"S0033291716003615_ref30","doi-asserted-by":"publisher","DOI":"10.1017\/S0033291702005834"},{"key":"S0033291716003615_ref33","doi-asserted-by":"publisher","DOI":"10.2217\/14622416.7.3.355"},{"key":"S0033291716003615_ref15","doi-asserted-by":"publisher","DOI":"10.1097\/PSY.0000000000000161"},{"key":"S0033291716003615_ref5","doi-asserted-by":"publisher","DOI":"10.1136\/bmjopen-2013-003973"},{"key":"S0033291716003615_ref2","doi-asserted-by":"publisher","DOI":"10.2217\/14622416.7.3.365"},{"key":"S0033291716003615_ref28","doi-asserted-by":"publisher","DOI":"10.1177\/014107689108400123"},{"key":"S0033291716003615_ref6","doi-asserted-by":"publisher","DOI":"10.1159\/000327582"},{"key":"S0033291716003615_ref8","doi-asserted-by":"publisher","DOI":"10.1016\/0022-3999(93)90081-P"},{"key":"S0033291716003615_ref13","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychores.2008.12.007"},{"key":"S0033291716003615_ref10","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-121-12-199412150-00009"},{"key":"S0033291716003615_ref19","doi-asserted-by":"publisher","DOI":"10.1097\/00006842-200203000-00008"},{"key":"S0033291716003615_ref38","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2377-7-6"},{"key":"S0033291716003615_ref29","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychores.2006.04.018"},{"key":"S0033291716003615_ref24","doi-asserted-by":"publisher","DOI":"10.1046\/j.1532-5415.2001.49124.x"},{"key":"S0033291716003615_ref36","doi-asserted-by":"crossref","first-page":"1050","DOI":"10.1176\/ajp.153.8.1050","article-title":"Psychological symptoms, somatic symptoms, and psychiatric disorder in chronic fatigue and chronic fatigue syndrome: a prospective study in the primary care setting","volume":"153","author":"Wessely","year":"1996","journal-title":"American Journal of Psychiatry"},{"key":"S0033291716003615_ref9","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpsychores.2015.12.006"}],"container-title":["Psychological Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0033291716003615","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,4,17]],"date-time":"2019-04-17T18:07:03Z","timestamp":1555524423000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0033291716003615\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,1,23]]},"references-count":41,"journal-issue":{"issue":"8","published-print":{"date-parts":[[2017,6]]}},"alternative-id":["S0033291716003615"],"URL":"https:\/\/doi.org\/10.1017\/s0033291716003615","relation":{},"ISSN":["0033-2917","1469-8978"],"issn-type":[{"value":"0033-2917","type":"print"},{"value":"1469-8978","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,1,23]]}}}