Letter to the Editor
Psychother Psychosom 2015;84:124–126 DOI: 10.1159/000365765
Abnormal Bodily Experiences Mediate the Relationship between Impulsivity and Binge Eating in Overweight Subjects Seeking Bariatric Surgery Giovanni Castellinia, b, Giovanni Stanghellinid, e, Lucia Godinia, c, Marcello Lucchesec, Francesca Trisolinid, e, Valdo Riccaa, a Psychiatric
Unit, Department of Neuropsychiatric Sciences, and b Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, Florence University School of Medicine, and c Bariatric Surgery Unit, Careggi Teaching Hospital, Florence, and d ‘G. d’Annunzio’ University, Chieti, Italy; e ‘D. Portales’ University, Santiago, Chile
According to different authors, most of the eating disorder (ED) features and behaviours such as dieting and binge eating should be considered secondary epiphenomena of a profound psychopathological core [1–3]. It has been hypothesized that identity impairments could have a role in the development of a distorted body weight self-conception, and accordingly in the onset and maintenance of the cognitive, affective and behavioural symptomatology characterizing EDs [4]. Moreover, it has been observed that ED patients show a peculiar disturbance in the way in which they experience their own body and shape their personal identity, thus suggesting that the various ED syndromes could be a consequence of such a disturbance [5]. On empirical grounds, in a previous study [5] we validated a self-reported questionnaire named IDEA (Identity and Eating Disorders) assessing abnormalities in lived corporeality and of personal identity. Briefly, the severity of abnormal bodily experiences and identity disorders, measured by IDEA total score, was found to be positively associated with the overvaluation of body shape and body weight of patients with anorexia nervosa, bulimia nervosa and binge ED [5]. Obese patients seeking bariatric surgery often show impulsive traits, high psychiatric comorbidity, and relevant ED-specific psychopathological features [6, 7]. In the ED population, impulsivity has been associated with binge eating and purging [8]. Taking into account a dimensional approach which considers that ED psychopathology is distributed along with a continuum of severity (from a high-risk population to full-blown ED patients), in the present study we administered IDEA to a sample of morbidly obese patients seeking bariatric surgery. The aims of the present study were to evaluate (1) whether the IDEA scores were associated with ED core features in a population of morbidly obese subjects and (2) the role of abnormal bodily ex-
© 2014 S. Karger AG, Basel 0033–3190/14/0842–0124$39.50/0 E-Mail [email protected] www.karger.com/pps
periences measured by IDEA in mediating the specific relationship between impulsivity and ED features. Two hundred and four obese patients (158 women; 77.5%; mean age: 43.4 ± 12.3 years; mean BMI: 44.37 ± 9.69) attending the Obesity Surgery Clinic of the Florence University School of Medicine (Italy) were assessed by means of the Structured Clinical Interview for DSM-IV and several self-reported questionnaires, including the IDEA questionnaire, the Eating Disorder Examination Questionnaire (EDE-Q), the Binge Eating Scale (BES), the Symptom Checklist (SCL-90-R), the Barratt Impulsiveness Scale (BISII), the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI Form Y-1). The bariatric surgery group was compared to a sample of 140 ED patients enrolled at the Outpatient Clinic for Eating Disorders of the University of Florence. The sample included 50 anorexia nervosa patients (45 women; 95.7%; mean age: 24.3 ± 7.7 years; mean BMI: 16.12 ± 1.39), 47 bulimia nervosa patients (45 women; 95.7%; mean age: 27.8 ± 9.05 years; BMI: 23.42 ± 6.05) and 46 binge ED patients (42 women; 91.3%; mean age: 34.9 ± 12.6 years; BMI: 38.07 ± 8.45) as well as a group of 145 healthy, normal-weight control subjects (113 women; 77.9%; mean age: 28.5 ± 5.6 years; BMI: 22.07 ± 3.01) recruited among students and residents by means of advertising at the university. Univariate analyses of variance and the χ2 test were adopted for between-group comparisons. Correlation analyses (Pearson’s correlation) and subsequently linear regression analyses were performed within each group, to assess the associations between IDEA scores and ED features as well as with other psychopathological variables. Mediator effect analyses were performed. Within bariatric patients, 96 subjects (47.1%) reported at least one objective binge eating episode in the preceding month, with a median number (quartiles) of objective and subjective binge episodes of 1 (0; 3) and 2 (1; 3), respectively, and a mean ± SD BES score of 16.8 ± 9.6. Furthermore, 58 subjects (28.4%) had a lifetime diagnosis of binge ED according to DSM-V criteria. No patient reported a gender dysphoria disorder. Healthy controls, bariatric surgery and ED patients showed significant differences in terms of IDEA total scores (F = 32.55; p < 0.001). In particular, IDEA scores were found to vary along a continuum of severity from healthy control subjects (reporting the lowest IDEA total score: 0.49 ± 0.54) up to ED patients [reporting the highest IDEA scores, without significant differences between anorexia nervosa (1.56 ± 0.88), bulimia nervosa (1.67 ± 1.06) and binge ED (1.56 ± 0.94)]; bariatric surgery patients reported intermediate IDEA scores (total score: 1.11 ± 0.71). IDEA total scores were directly correlated with EDE-Q total score and with BES in bariatric surgery patients (age- and BMIadjusted β: β = 0.64, p < 0.001 and β = 0.56, p < 0.001, respectively), while they did not show any significant association with SCL-90, BDI or STAI scores (data not shown). According to a previous study of our group [8], impulsivity (BIS total score) was correlated with both binge eating severity (BES) and ED psychopathology (EDE-Q scores). In order to evaluate the possible mechanisms that
Valdo Ricca, MD Psychiatric Unit, Department of Neuropsychiatric Sciences Florence University School of Medicine Largo Brambilla 3, IT–50134 Florence (Italy) E-Mail valdo.ricca @ unifi.it
Downloaded by: UCSF Library & CKM 169.230.243.252 - 3/5/2015 10:16:27 PM
Received: May 5, 2014 Accepted after revision: July 4, 2014 Published online: February 21, 2015
Color version available online
a
b
could explain the associations of impulsivity with EDE-Q and BES, mediator effect analyses were performed. According to Baron and Kenny [9], the following conditions supported the mediation hypothesis (fig. 1): (a) variations in the levels of the independent variable (impulsivity) significantly accounted for variations in the mediator (IDEA total score), (b) variations in the mediator signifi-
cantly accounted for variations in the dependent variable (EDE-Q total score), (c) variations in the independent variable significantly accounted for variations in the dependent variable, and (d) finally, when paths (a) and (b) were controlled, this previously significant relation between impulsivity and EDE-Q was no longer significant, while the relation between IDEA and EDE-Q retained its signifi-
Abnormal Bodily Experiences in Bariatric Surgery Patients
Psychother Psychosom 2015;84:124–126 DOI: 10.1159/000365765
125
Downloaded by: UCSF Library & CKM 169.230.243.252 - 3/5/2015 10:16:27 PM
Fig. 1. Mediation effect of the IDEA total score between impulsivity and eating psychopathology (a) and between impulsivity and binge eating (b). a Linear regression coefficients for the relationships between the independent variable (BIS total score), the dependent variable (EDE-Q total score) and the mediator (IDEA total score). b Linear regression coefficients for the relationships between the independent variable (BIS total score), the dependent variable (BES total score) and the mediator (IDEA total score). The Sobel test was performed in order to calculate the indirect effect of the BIS on the dependent variables via the mediator (IDEA total score).
126
Psychother Psychosom 2015;84:124–126 DOI: 10.1159/000365765
over, it is possible that one’s own identity and self-perception change over time, especially after a bariatric intervention. Therefore, long-term follow-up studies are needed to confirm the preliminary conclusions of the present study.
References 1 Fairburn CG, Harrison PJ: Eating disorders. Lancet 2003;361:407–416. 2 Allen KL, Byrne SM, McLean NJ, Davis EA: Overconcern with weight and shape is not the same as body dissatisfaction: evidence from a prospective study of pre-adolescent boys and girls. Body Image 2008;5:261–270. 3 Bardone-Cone AM, Harney MB, Maldonado CR, Lawson MA, Robinson DP, Smith R, Tosh A: Defining recovery from an eating disorder: conceptualization, validation, and examination of psychosocial functioning and psychiatric comorbidity. Behav Res Ther 2010;48:194–202. 4 Stein KF, Corte C: Identity impairment and the eating disorders: content and organization of the self-concept in women with anorexia nervosa and bulimia nervosa. Eur Eat Disord Rev 2007;15:58–69. 5 Stanghellini G, Castellini G, Brogna P, Faravelli C, Ricca V: Identity and Eating Disorders (IDEA): a questionnaire evaluating identity and embodiment in eating disorder patients. Psychopathology 2012;45:147–158. 6 Castellini G, Godini L, Amedei SG, Galli V, Alpigiano G, Mugnaini E, Veltri M, Rellini AH, Rotella CM, Faravelli C, Lucchese M, Ricca V: Psychopathological similarities and differences between obese patients seeking surgical and non-surgical overweight treatments. Eat Weight Disord 2014;19:95–102. 7 Malik S, Mitchell JE, Engel S, Crosby R, Wonderlich S: Psychopathology in bariatric surgery candidates: a review of studies using structured diagnostic interviews. Compr Psychiatry 2014;55:248–259. 8 Castellini G, Mannucci E, Lo Sauro C, Benni L, Lazzeretti L, Ravaldi C, Rotella CM, Faravelli C, Ricca V: Different moderators of cognitive-behavioral therapy on subjective and objective binge eating in bulimia nervosa and binge eating disorder: a three-year follow-up study. Psychother Psychosom 2012;81:11–20. 9 Baron RM, Kenny DA: The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol 1986;51:1173–1182. 10 Waxman SE: A systematic review of impulsivity in eating disorders. Eur Eat Disord Rev 2009;17:408–425.
Castellini/Stanghellini/Godini/Lucchese/ Trisolini/Ricca
Downloaded by: UCSF Library & CKM 169.230.243.252 - 3/5/2015 10:16:27 PM
cance, showing strong evidence for a single, dominant mediator. The same pattern was obtained when adopting the IDEA total score as a mediator of the relationship between impulsivity (BIS) and binge eating severity (BES). In order to calculate the indirect effect of BIS on EDE-Q and BES scores via the mediator (IDEA), the Sobel test was performed, and it turned out to be significant for both models (Z = 4.08, p < 0.001 and Z = 2.84, p = 0.004, respectively). Our results confirmed the hypothesis that abnormal bodily experiences are a core feature not just for ‘over-threshold’ ED patients but also for a high-risk population such as morbidly obese patients. IDEA scores express a gradient of vulnerability to ED psychopathology and behaviours from high-risk subjects (bariatric surgery subjects) up to the clinical groups. Therefore, we conclude that vulnerability to ED behaviours such as binge eating appeared to be associated with abnormal bodily experiences in a dimensional pattern. Moreover, according to our previous data [8], we found that also in morbidly obese patients individuals with a tendency towards impulsivity are more likely to engage in binge/ purge behaviours. Impulsivity, characterized by acting on the spur of the moment, without conscious judgment, and with the lack of adequate planning, is often associated with several pathological behaviours such as self-injury, stealing, sexual promiscuity and substance abuse [10]. Our mediation model seems to clarify that not impulsivity in itself, but the presence of impulsivity in persons affected by abnormal bodily experiences measured with IDEA, may lead to ED psychopathology and abnormal eating behaviours. Indeed, the IDEA score was also found to be a mediator for the relationship of impulsivity with both ED psychopathology (EDEQ scores) and binge eating in obese subjects. Therefore, we conclude that the disturbance in the lived corporeality may represent the core vulnerability trait which is one of the psychological characteristics underlying the association between personality traits such as impulsivity and the development of ED features. The main limitation of the present study is the cross-sectional design, which makes it difficult to ascertain a causal relationship between variables, even if the mediation model suggests this conclusion. More-
Psychother Psychosom 2015;84:124–126 DOI: 10.1159/000365765
Abnormal Bodily Experiences Mediate the Relationship between Impulsivity and Binge Eating in Overweight Subjects Seeking Bariatric Surgery Giovanni Castellinia, b, Giovanni Stanghellinid, e, Lucia Godinia, c, Marcello Lucchesec, Francesca Trisolinid, e, Valdo Riccaa, a Psychiatric
Unit, Department of Neuropsychiatric Sciences, and b Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, Florence University School of Medicine, and c Bariatric Surgery Unit, Careggi Teaching Hospital, Florence, and d ‘G. d’Annunzio’ University, Chieti, Italy; e ‘D. Portales’ University, Santiago, Chile
According to different authors, most of the eating disorder (ED) features and behaviours such as dieting and binge eating should be considered secondary epiphenomena of a profound psychopathological core [1–3]. It has been hypothesized that identity impairments could have a role in the development of a distorted body weight self-conception, and accordingly in the onset and maintenance of the cognitive, affective and behavioural symptomatology characterizing EDs [4]. Moreover, it has been observed that ED patients show a peculiar disturbance in the way in which they experience their own body and shape their personal identity, thus suggesting that the various ED syndromes could be a consequence of such a disturbance [5]. On empirical grounds, in a previous study [5] we validated a self-reported questionnaire named IDEA (Identity and Eating Disorders) assessing abnormalities in lived corporeality and of personal identity. Briefly, the severity of abnormal bodily experiences and identity disorders, measured by IDEA total score, was found to be positively associated with the overvaluation of body shape and body weight of patients with anorexia nervosa, bulimia nervosa and binge ED [5]. Obese patients seeking bariatric surgery often show impulsive traits, high psychiatric comorbidity, and relevant ED-specific psychopathological features [6, 7]. In the ED population, impulsivity has been associated with binge eating and purging [8]. Taking into account a dimensional approach which considers that ED psychopathology is distributed along with a continuum of severity (from a high-risk population to full-blown ED patients), in the present study we administered IDEA to a sample of morbidly obese patients seeking bariatric surgery. The aims of the present study were to evaluate (1) whether the IDEA scores were associated with ED core features in a population of morbidly obese subjects and (2) the role of abnormal bodily ex-
© 2014 S. Karger AG, Basel 0033–3190/14/0842–0124$39.50/0 E-Mail [email protected] www.karger.com/pps
periences measured by IDEA in mediating the specific relationship between impulsivity and ED features. Two hundred and four obese patients (158 women; 77.5%; mean age: 43.4 ± 12.3 years; mean BMI: 44.37 ± 9.69) attending the Obesity Surgery Clinic of the Florence University School of Medicine (Italy) were assessed by means of the Structured Clinical Interview for DSM-IV and several self-reported questionnaires, including the IDEA questionnaire, the Eating Disorder Examination Questionnaire (EDE-Q), the Binge Eating Scale (BES), the Symptom Checklist (SCL-90-R), the Barratt Impulsiveness Scale (BISII), the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI Form Y-1). The bariatric surgery group was compared to a sample of 140 ED patients enrolled at the Outpatient Clinic for Eating Disorders of the University of Florence. The sample included 50 anorexia nervosa patients (45 women; 95.7%; mean age: 24.3 ± 7.7 years; mean BMI: 16.12 ± 1.39), 47 bulimia nervosa patients (45 women; 95.7%; mean age: 27.8 ± 9.05 years; BMI: 23.42 ± 6.05) and 46 binge ED patients (42 women; 91.3%; mean age: 34.9 ± 12.6 years; BMI: 38.07 ± 8.45) as well as a group of 145 healthy, normal-weight control subjects (113 women; 77.9%; mean age: 28.5 ± 5.6 years; BMI: 22.07 ± 3.01) recruited among students and residents by means of advertising at the university. Univariate analyses of variance and the χ2 test were adopted for between-group comparisons. Correlation analyses (Pearson’s correlation) and subsequently linear regression analyses were performed within each group, to assess the associations between IDEA scores and ED features as well as with other psychopathological variables. Mediator effect analyses were performed. Within bariatric patients, 96 subjects (47.1%) reported at least one objective binge eating episode in the preceding month, with a median number (quartiles) of objective and subjective binge episodes of 1 (0; 3) and 2 (1; 3), respectively, and a mean ± SD BES score of 16.8 ± 9.6. Furthermore, 58 subjects (28.4%) had a lifetime diagnosis of binge ED according to DSM-V criteria. No patient reported a gender dysphoria disorder. Healthy controls, bariatric surgery and ED patients showed significant differences in terms of IDEA total scores (F = 32.55; p < 0.001). In particular, IDEA scores were found to vary along a continuum of severity from healthy control subjects (reporting the lowest IDEA total score: 0.49 ± 0.54) up to ED patients [reporting the highest IDEA scores, without significant differences between anorexia nervosa (1.56 ± 0.88), bulimia nervosa (1.67 ± 1.06) and binge ED (1.56 ± 0.94)]; bariatric surgery patients reported intermediate IDEA scores (total score: 1.11 ± 0.71). IDEA total scores were directly correlated with EDE-Q total score and with BES in bariatric surgery patients (age- and BMIadjusted β: β = 0.64, p < 0.001 and β = 0.56, p < 0.001, respectively), while they did not show any significant association with SCL-90, BDI or STAI scores (data not shown). According to a previous study of our group [8], impulsivity (BIS total score) was correlated with both binge eating severity (BES) and ED psychopathology (EDE-Q scores). In order to evaluate the possible mechanisms that
Valdo Ricca, MD Psychiatric Unit, Department of Neuropsychiatric Sciences Florence University School of Medicine Largo Brambilla 3, IT–50134 Florence (Italy) E-Mail valdo.ricca @ unifi.it
Downloaded by: UCSF Library & CKM 169.230.243.252 - 3/5/2015 10:16:27 PM
Received: May 5, 2014 Accepted after revision: July 4, 2014 Published online: February 21, 2015
Color version available online
a
b
could explain the associations of impulsivity with EDE-Q and BES, mediator effect analyses were performed. According to Baron and Kenny [9], the following conditions supported the mediation hypothesis (fig. 1): (a) variations in the levels of the independent variable (impulsivity) significantly accounted for variations in the mediator (IDEA total score), (b) variations in the mediator signifi-
cantly accounted for variations in the dependent variable (EDE-Q total score), (c) variations in the independent variable significantly accounted for variations in the dependent variable, and (d) finally, when paths (a) and (b) were controlled, this previously significant relation between impulsivity and EDE-Q was no longer significant, while the relation between IDEA and EDE-Q retained its signifi-
Abnormal Bodily Experiences in Bariatric Surgery Patients
Psychother Psychosom 2015;84:124–126 DOI: 10.1159/000365765
125
Downloaded by: UCSF Library & CKM 169.230.243.252 - 3/5/2015 10:16:27 PM
Fig. 1. Mediation effect of the IDEA total score between impulsivity and eating psychopathology (a) and between impulsivity and binge eating (b). a Linear regression coefficients for the relationships between the independent variable (BIS total score), the dependent variable (EDE-Q total score) and the mediator (IDEA total score). b Linear regression coefficients for the relationships between the independent variable (BIS total score), the dependent variable (BES total score) and the mediator (IDEA total score). The Sobel test was performed in order to calculate the indirect effect of the BIS on the dependent variables via the mediator (IDEA total score).
126
Psychother Psychosom 2015;84:124–126 DOI: 10.1159/000365765
over, it is possible that one’s own identity and self-perception change over time, especially after a bariatric intervention. Therefore, long-term follow-up studies are needed to confirm the preliminary conclusions of the present study.
References 1 Fairburn CG, Harrison PJ: Eating disorders. Lancet 2003;361:407–416. 2 Allen KL, Byrne SM, McLean NJ, Davis EA: Overconcern with weight and shape is not the same as body dissatisfaction: evidence from a prospective study of pre-adolescent boys and girls. Body Image 2008;5:261–270. 3 Bardone-Cone AM, Harney MB, Maldonado CR, Lawson MA, Robinson DP, Smith R, Tosh A: Defining recovery from an eating disorder: conceptualization, validation, and examination of psychosocial functioning and psychiatric comorbidity. Behav Res Ther 2010;48:194–202. 4 Stein KF, Corte C: Identity impairment and the eating disorders: content and organization of the self-concept in women with anorexia nervosa and bulimia nervosa. Eur Eat Disord Rev 2007;15:58–69. 5 Stanghellini G, Castellini G, Brogna P, Faravelli C, Ricca V: Identity and Eating Disorders (IDEA): a questionnaire evaluating identity and embodiment in eating disorder patients. Psychopathology 2012;45:147–158. 6 Castellini G, Godini L, Amedei SG, Galli V, Alpigiano G, Mugnaini E, Veltri M, Rellini AH, Rotella CM, Faravelli C, Lucchese M, Ricca V: Psychopathological similarities and differences between obese patients seeking surgical and non-surgical overweight treatments. Eat Weight Disord 2014;19:95–102. 7 Malik S, Mitchell JE, Engel S, Crosby R, Wonderlich S: Psychopathology in bariatric surgery candidates: a review of studies using structured diagnostic interviews. Compr Psychiatry 2014;55:248–259. 8 Castellini G, Mannucci E, Lo Sauro C, Benni L, Lazzeretti L, Ravaldi C, Rotella CM, Faravelli C, Ricca V: Different moderators of cognitive-behavioral therapy on subjective and objective binge eating in bulimia nervosa and binge eating disorder: a three-year follow-up study. Psychother Psychosom 2012;81:11–20. 9 Baron RM, Kenny DA: The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol 1986;51:1173–1182. 10 Waxman SE: A systematic review of impulsivity in eating disorders. Eur Eat Disord Rev 2009;17:408–425.
Castellini/Stanghellini/Godini/Lucchese/ Trisolini/Ricca
Downloaded by: UCSF Library & CKM 169.230.243.252 - 3/5/2015 10:16:27 PM
cance, showing strong evidence for a single, dominant mediator. The same pattern was obtained when adopting the IDEA total score as a mediator of the relationship between impulsivity (BIS) and binge eating severity (BES). In order to calculate the indirect effect of BIS on EDE-Q and BES scores via the mediator (IDEA), the Sobel test was performed, and it turned out to be significant for both models (Z = 4.08, p < 0.001 and Z = 2.84, p = 0.004, respectively). Our results confirmed the hypothesis that abnormal bodily experiences are a core feature not just for ‘over-threshold’ ED patients but also for a high-risk population such as morbidly obese patients. IDEA scores express a gradient of vulnerability to ED psychopathology and behaviours from high-risk subjects (bariatric surgery subjects) up to the clinical groups. Therefore, we conclude that vulnerability to ED behaviours such as binge eating appeared to be associated with abnormal bodily experiences in a dimensional pattern. Moreover, according to our previous data [8], we found that also in morbidly obese patients individuals with a tendency towards impulsivity are more likely to engage in binge/ purge behaviours. Impulsivity, characterized by acting on the spur of the moment, without conscious judgment, and with the lack of adequate planning, is often associated with several pathological behaviours such as self-injury, stealing, sexual promiscuity and substance abuse [10]. Our mediation model seems to clarify that not impulsivity in itself, but the presence of impulsivity in persons affected by abnormal bodily experiences measured with IDEA, may lead to ED psychopathology and abnormal eating behaviours. Indeed, the IDEA score was also found to be a mediator for the relationship of impulsivity with both ED psychopathology (EDEQ scores) and binge eating in obese subjects. Therefore, we conclude that the disturbance in the lived corporeality may represent the core vulnerability trait which is one of the psychological characteristics underlying the association between personality traits such as impulsivity and the development of ED features. The main limitation of the present study is the cross-sectional design, which makes it difficult to ascertain a causal relationship between variables, even if the mediation model suggests this conclusion. More-
