Psychotic episodes: markers of an eating disorder?
Authors: Stephan Zipfel, Katrin Giel
Journal: The Lancet Child & Adolescent Health (2018)

In The Lancet Child and Adolescent Health, Francesca Solmi and colleagues1Solmi F Melamed D Lewis G Kirkbride JB Longitudinal associations between psychotic experiences and disordered eating behaviours in adolescence: a UK population-based study.Lancet Child Adolesc Health. 2018; (published online June 21.)http://dx.doi.org/10.1016/S2352-4642(18)30180-9Summary Full Text Full Text PDF Scopus (11) Google Scholar present their analysis of data from more than 6000 children taken from the large longitudinal birth cohort study Avon Longitudinal Study of Parents and Children (ALSPAC; Bristol, UK). They investigated whether, and to what extent, psychotic experiences at the age of 13 years predict disordered eating behaviours 5 years later at age 18 years. The investigators noted that 734 (12%) of 6361 children reported psychotic experiences at age 13 years, and showed that in univariable models, psychotic experiences were associated with greater odds of reporting any disordered eating behaviours (odds ratio [OR] 1·92, 95% CI 1·46–2·52; p<0·0001), and more severe symptoms (as measured by the number of disordered eating behaviours: 0·58, 0·32–0·84; p<0·0001) at age 18 years. Solmi and colleagues' efforts are much appreciated and contribute to the urgently needed advancement of the evidence to identify risk factors for the development of an eating disorder.2Treasure J Zipfel S Micali N et al.Anorexia nervosa.Nat Rev Dis Primers. 2015; 1: 15074Crossref PubMed Scopus (183) Google Scholar Their findings are an especially important contribution to the scientific literature because the evidence for both eating disorders and psychotic experiences is rather scarce compared with that for other mental disorders, and patterns of trajectories into illness and comorbidities among mental disorders can inform models of the underlying structure of psychopathology including potential endophenotypes.3de Jonge P Wardenaar KJ Lim CCW et al.The cross-national structure of mental disorders: results from the World Mental Health Survey.Psychol Med. 2017; (published Dec 19: 1–12)Crossref Scopus (34) Google Scholar The database of this study and the rigorous analysis strategy enabled the consideration of a range of child and maternal confounding variables and provides well powered results. The results indicate that psychotic experiences might constitute an early risk factor for the development of an eating disorder. Taking a closer look, psychotic and eating disorders indeed share a range of clinical characteristics, including impairments in the domains of neurocognition, socioemotional regulation, and interpersonal skills. Accordingly, the investigators point out that concerns and cognitions that patients with eating disorders typically show around their disorder behaviour have sometimes been described as having delusional qualities. Of note, specific cognitive dysfunctions especially have been debated as potential endophenotypes of eating disorders, particularly anorexia nervosa.4Micali N Dahlgren CL All that glisters is not an endophenotype: rethinking endophenotypes in anorexia nervosa.Eur Child Adolesc Psychiatry. 2016; 25: 1149-1150Crossref PubMed Scopus (11) Google Scholar To qualify as an endophenotype, a marker has to fulfil certain criteria–heritability among others, and indeed, the findings by Solmi and colleagues nicely concur with findings from large, multinational genetic studies5Bulik-Sullivan B Finucane HK Anttila V et al.An atlas of genetic correlations across human diseases and traits.Nat Genet. 2015; 47: 1236-1241Crossref PubMed Scopus (1694) Google Scholar indicating a genetic correlation between anorexia nervosa and schizophrenia. However, a marker that is assumed to be an endophenotype should be state-independent (ie, independent of the disorder). This constitutes a special challenge in the field of eating disorder research to consider acute effects of the psychopathology, such as starvation, in anorexia nervosa and other physical consequences of malnutiriton, undernutrition, or overnutrition in eating disorders, which might also affect cognitive functioning. As previously outlined by other investigators in the field,4Micali N Dahlgren CL All that glisters is not an endophenotype: rethinking endophenotypes in anorexia nervosa.Eur Child Adolesc Psychiatry. 2016; 25: 1149-1150Crossref PubMed Scopus (11) Google Scholar risk-factor research into eating disorders requires more longitudinal studies such as Solmi and colleagues', which should be designed to be especially sensitive to physical consequences and scarring effects of eating disorders. However, psychotic experiences have been identified as predictors for the onset of a range of other mental disorders6McGrath JJ Saha S Al-Hamzawi A et al.The bidirectional associations between psychotic experiences and DSM-IV mental disorders.Am J Psychiatry. 2016; 173: 997-1006Crossref PubMed Scopus (138) Google Scholar and might not represent a risk factor specific for eating disorders, but rather constitute a non-specific risk factor for psychopathology, as Solmi and colleagues also discuss. Last, there might be a link between psychotic experiences and disturbed eating behaviour via a central clinical feature of eating disorders that has also been identified as a specific risk factor for these disorders, but was not included in the study by Solmi and colleagues:1Solmi F Melamed D Lewis G Kirkbride JB Longitudinal associations between psychotic experiences and disordered eating behaviours in adolescence: a UK population-based study.Lancet Child Adolesc Health. 2018; (published online June 21.)http://dx.doi.org/10.1016/S2352-4642(18)30180-9Summary Full Text Full Text PDF Scopus (11) Google Scholar ie, body image disturbances. Body dissatisfaction has been shown to be a specific risk factor for the onset of eating disorders,7Stice E Desjardins CD Interactions between risk factors in the prediction of onset of eating disorders: exploratory hypothesis generating analyses.Behav Res Ther. 2018; 105: 52-62Crossref PubMed Scopus (41) Google Scholar and at least in anorexia nervosa, distorted cognitions and beliefs—constituting a potential clinical link between psychosis and eating disorders—are a core feature of disturbed body image.8Mölbert SC Thaler A Mohler BJ et al.Assessing body image in anorexia nervosa using biometric self-avatars in virtual reality: attitudinal components rather than visual body size estimation are distorted.Psychol Med. 2018; 48: 642-653Crossref PubMed Scopus (91) Google Scholar Regarding clinical practice, several large-scale studies in adolescents with eating disorders in different treatment settings have shown family-based interventions for adolescents with a short duration of illness are highly effective.9Agras WS Lock J Brandt H et al.Comparison of 2 family therapies for adolescent anorexia nervosa: a randomized parallel trial.JAMA Psychiatry. 2014; 71: 1279-1286Crossref PubMed Scopus (173) Google Scholar, 10Herpertz-Dahlmann B Schwarte R Krei M et al.Day-patient treatment after short inpatient care versus continued inpatient treatment in adolescents with anorexia nervosa (ANDI): a multicentre, randomised, open-label, non-inferiority trial.Lancet. 2014; 383: 1222-1229Summary Full Text Full Text PDF PubMed Scopus (161) Google Scholar Progress has also been made in the area of adults with eating disorders,11Zipfel S Wild B Gross G et al.Focal psychodynamic therapy, cognitive behaviour therapy, and optimised treatment as usual in outpatients with anorexia nervosa (ANTOP study): randomised controlled trial.Lancet. 2014; 383: 127-137Summary Full Text Full Text PDF PubMed Scopus (269) Google Scholar and emerging treatments are more targeted towards specific deficits; eg, cognitive impairments, and use novel brain-directed interventions.12Brockmeyer T Friederich HC Schmidt U Advances in the treatment of anorexia nervosa: a review of established and emerging interventions.Psychol Med. 2018; 48: 1228-1256Crossref PubMed Scopus (92) Google Scholar These developments match well with the assumed clinical underpinnings of the findings from Solmi and colleagues' study,1Solmi F Melamed D Lewis G Kirkbride JB Longitudinal associations between psychotic experiences and disordered eating behaviours in adolescence: a UK population-based study.Lancet Child Adolesc Health. 2018; (published online June 21.)http://dx.doi.org/10.1016/S2352-4642(18)30180-9Summary Full Text Full Text PDF Scopus (11) Google Scholar which also point towards the need for targeted prevention for high-risk subgroups—although since psychotic experiences are potentially a non-specific risk factor, the findings predominantly inform transdiagnostic prevention efforts. We declare no competing interests. Longitudinal associations between psychotic experiences and disordered eating behaviours in adolescence: a UK population-based studyOur findings suggested that psychotic experiences are markers of increased risk for several disordered eating behaviours in late adolescence, possibly by indicating more severe psychopathology in early adolescence. More research investigating shared risk factors for psychotic experiences and eating disorders is warranted to elucidate shared and specific causal pathways. Full-Text PDF Open Access