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IDENTIFYING THE CORE SYMPTOMS OF BULIMIA NERVOSA AND ASSOCIATED ANXIETY AND DEPRESSION CHERI LEVINSON, STEPHANIE ZERWAS, BENJAMIN CALEBS, KELSIE FORBUSH, HUNNA WATSON, HANS KORDY, SARA HOFMEIER, MICHELE LEVINE, BENJAMIN ZIMMER, MARKUS MOESSNER, CHRISTINE PEAT, CRISTIN RUNFOLA, MARSHA MARCUS, CYNTHIA BULIK WHAT IS AT THE CORE OF BULIMIA NERVOSA? Bulimia nervosa (BN) is characterized by symptoms of: binge eating and compensatory behavior overevaluation of weight and shape BN symptoms often co-occur with symptoms of anxiety and depression Which specific BN symptoms maintain BN psychopathology? How are these symptoms associated with symptoms of depression and anxiety? Fairburn, Cooper, & Shafran, 2003; Palister & Waller, 2008 MODELS OF PSYCHOPATHOLOGY Latent variable theory often used to describe why mental disorders develop & persist Symptoms arise from a common cause BN Fear of weight gain Binge eating Purging Avoidance of food BN is the cause that leads to each of these common symptoms. Bollen, 2002; Borsboom et al., 2016; Clark & Watson, 1991; Eaton, 2015; Haslam, Holland, & Kuppens, 2012 NETWORK THEORY Network theory proposes that symptoms of disorders cause each other Symptoms are part of a dynamic network which can produce, sustain, and underlie mental disorders Fear of Weight Gain Avoidance of food Binge eating Purging These interact with each other to strengthen (or weaken) the disorder Borsboom & Cramer, 2010; Borsboom & Cramer, 2013; Kendler, Zachar, & Craver, 2011 WHAT CAN NETWORK ANALYSIS TEACH US? Determine the symptoms that are central to the BN psychopathology network Examine how symptoms of comorbid disorders interact with symptoms of BN CLINICAL UTILITY Reducing core symptoms in treatment should theoretically also decrease related symptoms Focus interventions to target: core symptoms−symptoms play a crucial role in the network comorbid symptoms that link between multiple disorders Hayes, Yasinski, Barnes, & Bockting, 2015 CURRENT STUDY Examined: 1. A network of BN symptoms: Which symptoms are most central (i.e. core symptoms)? 2. The networks of BN, depression, and anxiety symptoms: Which depression and anxiety symptoms are most strongly related to BN symptoms? PARTICIPANTS 196 patients recruited for a clinical trial All patients had DSM-IV diagnosis of BN Primarily female (n = 187; 95.4%) European American (n = 165; 84.2%) Majority had comorbid depression and/or anxiety (n = 136; 69.4%) MEASURES Eating Disorder Examination Binge eating, restriction, fears of fatness Short Evaluation of Eating Disorders Vomiting, purging, excessive exercise Beck Anxiety Inventory Scared, dizziness Beck Depression Inventory-II Sad, fatigue, self-dislike Bauer et al., 2005; Beck, Steer, & Brown, 1996; Fairburn & Cooper, 1993; Steer & Beck, 1997 NETWORK ANALYSES Partial Correlation Networks (Glasso Estimator) Explains how symptoms relate while also considering the impact of all other symptoms Bridge Symptoms Symptoms that link adjacent symptoms together and are theorized to be pathways that could causally connect symptoms or behaviors Centrality Measures Betweenness – number of times symptom is passed through Closeness – closeness to other symptoms in the network Strength – having many connections to other symptoms BN Network BULIMIA NERVOSA PSYCHOPATHOLOGY NETWORK CLOSENESS BETWEENESS Betweenness STRENGTH Closeness Strength **weight preoccupation wtpreoc wtimport **weight dissatisfaction ** wtdis weigh vomit socialeat shapeimport shapedis secreteat restrict Higher peaks on right side indicate higher centrality preoc overeat losscontrol ** weight **lose losewt guilt **highest centrality items foodavoid flatstom feelfat **fear weight gain ** fearwtgain fast expodisc excesexer emptystom dietrule bodydisc binge avoideat −1 0 1 2 −2 −1 0 1 −2 −1 0 1 exces exer fast empty stom hot BN AND ANXIETY NETWORK avoid eat flat stom food avoid sweat over eat restrict weigh diet rule dizzy faint un steady lose wt feel fat expo disc body disc shape import Bulimia Nervosa & Anxiety Network heart pound terrified shaky diffb choking nervous cant relax scared tingle social eat wtdis wt import lose control guilt shape dis face flush wobble hand tremble fear wtgain indiges tion fear worst wt preoc secret eat loss control preoc vomit binge fear die BETWEENESS **weight preoccupation ** CLOSENESS Betweenness STRENGTH Closeness Strength wtpreoc wtimport wtdis wobble weigh vomit **unsteady **terrified unsteady tingle terrified sweat socialeat **shapedis **shape dissatisfaction shaky shapeimport Higher peaks on right side indicate higher centrality secreteat scared restrict preoc overeat nervous losscontrol losewt ** losecontrol **lose control indigestion hot **highest centrality items heartpound handtremble guilt foodavoid flatstom feelfat **fear weight gain **fearwtgain fearworst feardie fast faint faceflush expodisc excesexer emptystom dizzy diffb **choking ** dietrule choking cantrelax bodydisc binge ** eating **avoid avoideat −1 0 1 2 −4 −3 −2 −1 0 1 −2 −1 0 1 exces exer over eat restrict food avoid fast weigh diet rule flat stom fear wtgain avoid eat empty stom BN AND DEPRESSION NETWORK agita tion self dislike inde cisive irritable loss pleasure sleep fatigue Bulimia Nervosa & critical punish low energy Depression Network loss interest worth less sad shape import expo disc secret eat body disc wt preoc past fail preoc appetite pessim con centrate wt import feel fat shape dis guilty guilt lose wt wtdis crying social eat suicide sex vomit binge loss control BETWEENESS **weight preoccupation CLOSENESS Betweenness ** STRENGTH Closeness Strength wtpreoc wtimport wtdis worthless weigh vomit suicide socialeat sleep shapeimport shapedis sex selfdislike secreteat ** **sad sad restrict punish preoc pessim pastfail Higher peaks on right side indicate higher centrality overeat lowenergy losspleasure lossinterest losscontrol losewt **irritable ** irritable indecisive guilty guilt foodavoid **highest centrality items flatstom feelfat **fear weight gain fearwtgain ** fatigue fast expodisc excesexer emptystom dietrule crying critical **concentrate concentrate ** bodydisc binge avoideat appetite agitation −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 CONCLUSIONS Core BN symptoms fear of weight gain & overevaluation of weight and shape Bridge symptoms - connect anxiety or depression symptoms to BN Physical sensations: unsteady, fears of losing control, choking, difficulty concentrating may be bridge symptoms FEAR OF WEIGHT GAIN Fear of weight gain is central to BN network Binge eating and purging on the periphery Treatments that focus on fear of weight gain may have maximal impact Weekly weighing Exposure PHYSICAL SENSATIONS Physical sensations bridge BN & anxiety/depression Exaggerated insula response in eating disorders? Sensitivity to physical sensations Interoceptive Exposures Kim et al., 2012; Fassino, Pierò, Gramaglia, & Abbate-Daga, 2004; Klabunde et al., 2013; Oberndorfer et al., 2013 LIMITATIONS Data is cross-sectional – no causality Limited measurement of each symptom Applying network analysis to psychopathology is new No fit indices No measures of reliability Limited by measures and symptoms chosen for the network FUTURE DIRECTIONS Does change in a core symptom produce changes in other network symptoms? Do symptom networks become less strong after treatment and with symptom remission? ACKNOWLEDGMENTS & DISCLOSURES Dr. Bulik is a grant recipient and consultant for Shire Pharmaceuticals and has consulted for Ironshore. Dr. Marcus is on the Scientific Advisory Board of Weight Watchers International, Inc. Dr. Peat is recipient of a contract from RTI and Shire Pharmaceuticals and has consulted for Sunovion Pharmaceuticals, L.E.K consulting, and Nexus Global Solutions. Dr. Watson is supported by a research grant from Shire awarded to UNC-Chapel Hill. Dr. Zerwas has consulted for L.E.K consulting. This research was supported by a National Institute of Mental Health (NIMH) grant (R01MH080065), a Clinical Translational Science Award (UL1TR000083), and the Alexander von Humboldt-Stiftung. Dr. Zerwas is supported by a NIMH career development grant (K01MH100435). Drs. Peat and Runfola were supported by a NIMH post-doctoral training grant (T32MH076694). Dr. Runfola was supported by the Global Foundation for Eating Disorders (PIs: Bulik and Baucom; www.gfed.org). Benjamin Zimmer was supported by a Fellowship for Postdoctoral Researchers from the German Academic Exchange Service (DAAD). Dr. Bulik acknowledges support from the Swedish Research Council (VR Dnr: 538-2013-8864). We wish to honor the incredible contribution and legacy of our colleague Dr. Robert Hamer, who passed away in December 2015.