Associations between self-induced vomiting and personality disorder in patients with a history of anorexia nervosa Dowson JH. Associations between self-induced vomiting and personality disorder in patients with a history of anorexia nervosa. Acta Psychiatr Scand 1992: 86: 399-404. 0 Munksgaard 1992. Fifty-five patients of an eating disorders service with a history of anorexia nervosa (AN), defined by a history of refusal to maintain body weight above a level of 15:h below that expected, completed a modified version of the revised Personality Diagnostic Questionnaire (PDQ-R) based on DSM-111-R personality disorders (PD). The subjects were divided into 2 groups based on AN subtypes: vomiters, defined by a history of self-induced vomiting, and non-vomiters, who had maintained low weight mainly or only by diet 2 excessive exercise. Vomiters showed significantly higher scores on self-report measures of borderline and antisocial P D criteria. Discriminant analysis based on P D scores for all 13 DSM-111-R P D categories correctly predicted AN subtype membership based on vomiting history in 85.5% of patients. The implications of P D comorbidity for the development and management of eating disorders are discussed.
The main distinction between subtypes of psychogenic eating disorders has been between anorexia nervosa (AN) in patients who have achieved and maintained low weight by a restrictive diet, perhaps with excessive exercise (restricters or dieters), and AN in patients who have shown various combinations and patterns of bulimia, self-induced vomiting and laxative abuse (vomiters and purgers, bulimics, bulimic anorectics, low-weight bulimics or non-restricters) (1-8). It has also been suggested that a distinct subtype of bulimia nervosa (BN) is associated with patients who show relatively small deviations from normal weight (i.e. normal-weight bulimics) (8- 10) and that low-weight bulimics may be more closely related to normal-weight bulimics than to restricters (1 1). Most studies of AN subtypes have involved bulimia as the distinguishing feature, although Beumont et al. (3) used vomiting and purging. It has been suggested that the nature and degree of comorbid personality disorder (PD) can have major effects on the prognosis of eating disorders and should be an important factor in deciding treatment strategy (12-16). Borderline P D has been reported to be common in patients with eating disorders (17-19) and several studies have described a variety of PD psychopathology associated with bulimia, i.e., histrionic, borderline, schizoid, schizotypal, antisocial, narcissistic, obsessive-compulsive,
J. H. Dowson Cambridge University Department of Psychiatry, Addenbrooke’s Hospital, Cambridge, United Kingdom
Key words: personality disorder; borderline personality disorder; antisocial personality disorder; anorexia nervosa Dr J.H. Dowson, Cambridge University Department of Psychiatry, Level E4, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2 0 0 , United Kingdom Accepted for publication July 19, 1992
avoidant, dependent and passive-aggressive PD ( 5 , 17,20-28), although Pope et al. (29) concluded that their results argued against a specific relationship between bulimia and borderline PD in patients with normal-weight bulimia. However, although this study found no difference in borderline PD ratings between patients with bulimia and another group with major depression, both these groups had higher borderline ratings than the non-psychiatric control group. Also, a relatively high degree of obsessivecompulsive PD traits has been described in restricters and it was suggested that this can be of aetiological significance (3). Several studies have reported personality differences between restricters and the patients with a history of bulimia or vomiting and purging. Beumont et al. (3), using unstructured interviews, investigated 3 1 patients divided into dieters and vomiters & purgers, although occasional vomiting did not disqualify a patient from the former group. Histrionic traits (considered as childish behaviour, affective instability, evanescent enthusiasm, dramatic exaggerations and the impression of emotional shallowness) were much more prevalent in the vomiters and purgers, and obsessional traits (i.e. reliability, precision, scrupulousness, conscientiousness and love of order and discipline) and social withdrawal were more common in the dieters. Casper et al. (4) studied 105 inpatients with AN using the Minnesota Multiphasic
399
Dowson Personality Inventory (MMPI) and found that frequency ofbulimia was associated with various MMPI scale scores, including the psychopathic deviate scale. In contrast to the fasting (i.e., restricter) patients, those with bulimia were more extroverted and more likely to steal. Garfinkel et al. ( 5 ) reported a series of 141 patients with AN who were divided into restricters and bulimics on the basis of recent history at the initial consultation, although some restricters had a history of vomiting. Various intergroup differences were found, including an association between bulimia, premorbid obesity and family history of obesity. Also, the bulimic group were more outgoing, less isolated and more involved sexually. Their moods were more labile and they showed more impulsive behaviour such as self-harm (suicide attempts and self-mutilation), stealing and abuse of alcohol and street drugs. Piran et al. (30) described similar findings using the Diagnostic Interview for Borderline Patients as well as structured interviews: 60% of the restricters received a diagnosis of avoidant PD, and the most common P D diagnosis in the bulimic group (i.e. in those with AN and bulimia) was borderline P D in 55.3% compared with only 6.6% in the restricters. However, the consensus in the above studies was not sustained by Gartner et al. (17) in their report of DSM-111-R P D in 35 inpatients using a structured interview, as they found no evidence of significant P D differences between restricters and those with low-weight bulimia, although the number of restricters was small (n = 6). Therefore, although most reports that have compared subtypes of AN have found that low-weight bulimia is associated with P D characteristics related to impulsive and harmful behaviour, this was not confirmed in the only study that used a standard structured interview method for the assessment of all the DSM-111-R PD. The present study aimed to investigate the relationships between eating disorder subtypes and DSM-111-R P D using a previously-validated selfreport questionnaire. The implications of the results for the aetiology and management of patients with eating disorders are then discussed. Material and methods Assessment
The revised Personality Diagnostic Questionnaire (PDQ-R) takes about 30 minutes to complete and has 152 questions that are answered as true or false (31-34). The patient scores each of the criteria for the DSM-111-R classification of P D (35) as present or absent. Previously reported modifications have been made in an attempt to increase the face validity of questions in relation to DSM-111-R P D criteria and to increase compliance by referring to odd or
400
socially undesirable behaviour in a less perjorative way (36). The complete modified version is available from the author together with the scoring system, which takes into account the minority of criteria that contribute to more than one PD. A short version of the modified PDQ-R provides the questions relating to selected P D including borderline P D (36). For the second DSM-111-R criterion for borderline PD, binge eating is one of the range of behaviours that are evaluated as examples of impulsivity, and a minimum of 2 of the specified behaviours are required for the criterion to be rated as positive. However, in the present study, this criterion was not rated as positive if it depended on the presence of binge eating. DSM-111-R antisocial P D was evaluated in respect of behaviour both before and after the age of 15 to determine the prevalence of antisocial PD, but in determining the antisocial P D score (i.e., number of positive criteria), only the 10 criteria relating to behaviour since the age of 15 were used. Patients
The modified PDQ-R was completed by patients of an eating disorders clinic that formed part of a comprehensive adult psychiatric service. The findings are reported for the first 55 patients who gave a history of the first of the DSM-111-R criteria for AN: “refusal to maintain body weight over a minimal normal weight for age and height, e.g. weight loss leading to maintenance of body weight 15% below that expected; or failure to make expected weight gain during period of growth, leading to body weight 15% below that expected”. The expected weight was defined by the mean of the range for medium frame in the tables prepared by the Metropolitan Life Insurance Company (39). There was no history of other disorders that could account for the low weight, including major affective disorder and schizophrenia. A history of bulimia was evaluated in these patient using the first DSM-111-R criterion for bulimia nervosa: “recurrent episodes of binge eating (rapid consumption of a large amount of food in a discrete period of time)”. As the aim was to investigate associations of P D and eating disorders in the majority of patients who presented, the identification of a history of AN was designed to select the majority of patients who presented with a history of psychogenic low weight. These patients showed various degrees of similarity to the ideal (i.e. prototype) syndrome, but all had shown the core feature of psychogenic weight loss involving a refusal to maintain a normal body weight. However, all patients who received a diagnosis of AN in the present study could be said to fulfil (or have fulfilled) ICD-9 requirements for AN (37), although the ICD- 10 classification requires addi-
Personality and eating disorders
tional criteria for a “definite” diagnosis (38). Also, as the psychological criteria for AN and bulimia nervosa (35, 38) are relatively difficult to evaluate reliably, in particular for past episodes, the use of the weight criterion alone for AN, and the binge eating criterion alone for bulimia, were designed to identify groups of patients in ways that could be reliably replicated. The identification of AN, vomiting and bulimia were made in relation to the patient’s history of eating disorder and not just to the recent (i.e., past 3 months) and presenting features. If personality disorder (which involves long-term patterns of behaviour) is related to vomiting and bulimia, then a previous history of these features is likely to be relevant in grouping patients on a basis that has associations with PD, even if they are absent from the recent history. The patient’s description of binge eating had to be judged by the author to involve and abnormally large amount of food to qualify for the diagnosis of bulimia. A history of vomiting was identified if the subject had induced vomiting on more than one occasion for the purpose of weight control. Statistics
The statistical analysis was carried out with the SPSSjPC program (40). Comparisons between means were made with t-tests (2-tailed) or with Bonferroni t-tests to allow for multiple comparisons. For x = the number of related t-tests, the significancelevel yielded by the t-test needed to be 0.05 divided by x to be considered significant at the 0.05 level (41). The pooled-variance t-test was used unless an F-test indicated significant (P
The main distinction between subtypes of psychogenic eating disorders has been between anorexia nervosa (AN) in patients who have achieved and maintained low weight by a restrictive diet, perhaps with excessive exercise (restricters or dieters), and AN in patients who have shown various combinations and patterns of bulimia, self-induced vomiting and laxative abuse (vomiters and purgers, bulimics, bulimic anorectics, low-weight bulimics or non-restricters) (1-8). It has also been suggested that a distinct subtype of bulimia nervosa (BN) is associated with patients who show relatively small deviations from normal weight (i.e. normal-weight bulimics) (8- 10) and that low-weight bulimics may be more closely related to normal-weight bulimics than to restricters (1 1). Most studies of AN subtypes have involved bulimia as the distinguishing feature, although Beumont et al. (3) used vomiting and purging. It has been suggested that the nature and degree of comorbid personality disorder (PD) can have major effects on the prognosis of eating disorders and should be an important factor in deciding treatment strategy (12-16). Borderline P D has been reported to be common in patients with eating disorders (17-19) and several studies have described a variety of PD psychopathology associated with bulimia, i.e., histrionic, borderline, schizoid, schizotypal, antisocial, narcissistic, obsessive-compulsive,
J. H. Dowson Cambridge University Department of Psychiatry, Addenbrooke’s Hospital, Cambridge, United Kingdom
Key words: personality disorder; borderline personality disorder; antisocial personality disorder; anorexia nervosa Dr J.H. Dowson, Cambridge University Department of Psychiatry, Level E4, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2 0 0 , United Kingdom Accepted for publication July 19, 1992
avoidant, dependent and passive-aggressive PD ( 5 , 17,20-28), although Pope et al. (29) concluded that their results argued against a specific relationship between bulimia and borderline PD in patients with normal-weight bulimia. However, although this study found no difference in borderline PD ratings between patients with bulimia and another group with major depression, both these groups had higher borderline ratings than the non-psychiatric control group. Also, a relatively high degree of obsessivecompulsive PD traits has been described in restricters and it was suggested that this can be of aetiological significance (3). Several studies have reported personality differences between restricters and the patients with a history of bulimia or vomiting and purging. Beumont et al. (3), using unstructured interviews, investigated 3 1 patients divided into dieters and vomiters & purgers, although occasional vomiting did not disqualify a patient from the former group. Histrionic traits (considered as childish behaviour, affective instability, evanescent enthusiasm, dramatic exaggerations and the impression of emotional shallowness) were much more prevalent in the vomiters and purgers, and obsessional traits (i.e. reliability, precision, scrupulousness, conscientiousness and love of order and discipline) and social withdrawal were more common in the dieters. Casper et al. (4) studied 105 inpatients with AN using the Minnesota Multiphasic
399
Dowson Personality Inventory (MMPI) and found that frequency ofbulimia was associated with various MMPI scale scores, including the psychopathic deviate scale. In contrast to the fasting (i.e., restricter) patients, those with bulimia were more extroverted and more likely to steal. Garfinkel et al. ( 5 ) reported a series of 141 patients with AN who were divided into restricters and bulimics on the basis of recent history at the initial consultation, although some restricters had a history of vomiting. Various intergroup differences were found, including an association between bulimia, premorbid obesity and family history of obesity. Also, the bulimic group were more outgoing, less isolated and more involved sexually. Their moods were more labile and they showed more impulsive behaviour such as self-harm (suicide attempts and self-mutilation), stealing and abuse of alcohol and street drugs. Piran et al. (30) described similar findings using the Diagnostic Interview for Borderline Patients as well as structured interviews: 60% of the restricters received a diagnosis of avoidant PD, and the most common P D diagnosis in the bulimic group (i.e. in those with AN and bulimia) was borderline P D in 55.3% compared with only 6.6% in the restricters. However, the consensus in the above studies was not sustained by Gartner et al. (17) in their report of DSM-111-R P D in 35 inpatients using a structured interview, as they found no evidence of significant P D differences between restricters and those with low-weight bulimia, although the number of restricters was small (n = 6). Therefore, although most reports that have compared subtypes of AN have found that low-weight bulimia is associated with P D characteristics related to impulsive and harmful behaviour, this was not confirmed in the only study that used a standard structured interview method for the assessment of all the DSM-111-R PD. The present study aimed to investigate the relationships between eating disorder subtypes and DSM-111-R P D using a previously-validated selfreport questionnaire. The implications of the results for the aetiology and management of patients with eating disorders are then discussed. Material and methods Assessment
The revised Personality Diagnostic Questionnaire (PDQ-R) takes about 30 minutes to complete and has 152 questions that are answered as true or false (31-34). The patient scores each of the criteria for the DSM-111-R classification of P D (35) as present or absent. Previously reported modifications have been made in an attempt to increase the face validity of questions in relation to DSM-111-R P D criteria and to increase compliance by referring to odd or
400
socially undesirable behaviour in a less perjorative way (36). The complete modified version is available from the author together with the scoring system, which takes into account the minority of criteria that contribute to more than one PD. A short version of the modified PDQ-R provides the questions relating to selected P D including borderline P D (36). For the second DSM-111-R criterion for borderline PD, binge eating is one of the range of behaviours that are evaluated as examples of impulsivity, and a minimum of 2 of the specified behaviours are required for the criterion to be rated as positive. However, in the present study, this criterion was not rated as positive if it depended on the presence of binge eating. DSM-111-R antisocial P D was evaluated in respect of behaviour both before and after the age of 15 to determine the prevalence of antisocial PD, but in determining the antisocial P D score (i.e., number of positive criteria), only the 10 criteria relating to behaviour since the age of 15 were used. Patients
The modified PDQ-R was completed by patients of an eating disorders clinic that formed part of a comprehensive adult psychiatric service. The findings are reported for the first 55 patients who gave a history of the first of the DSM-111-R criteria for AN: “refusal to maintain body weight over a minimal normal weight for age and height, e.g. weight loss leading to maintenance of body weight 15% below that expected; or failure to make expected weight gain during period of growth, leading to body weight 15% below that expected”. The expected weight was defined by the mean of the range for medium frame in the tables prepared by the Metropolitan Life Insurance Company (39). There was no history of other disorders that could account for the low weight, including major affective disorder and schizophrenia. A history of bulimia was evaluated in these patient using the first DSM-111-R criterion for bulimia nervosa: “recurrent episodes of binge eating (rapid consumption of a large amount of food in a discrete period of time)”. As the aim was to investigate associations of P D and eating disorders in the majority of patients who presented, the identification of a history of AN was designed to select the majority of patients who presented with a history of psychogenic low weight. These patients showed various degrees of similarity to the ideal (i.e. prototype) syndrome, but all had shown the core feature of psychogenic weight loss involving a refusal to maintain a normal body weight. However, all patients who received a diagnosis of AN in the present study could be said to fulfil (or have fulfilled) ICD-9 requirements for AN (37), although the ICD- 10 classification requires addi-
Personality and eating disorders
tional criteria for a “definite” diagnosis (38). Also, as the psychological criteria for AN and bulimia nervosa (35, 38) are relatively difficult to evaluate reliably, in particular for past episodes, the use of the weight criterion alone for AN, and the binge eating criterion alone for bulimia, were designed to identify groups of patients in ways that could be reliably replicated. The identification of AN, vomiting and bulimia were made in relation to the patient’s history of eating disorder and not just to the recent (i.e., past 3 months) and presenting features. If personality disorder (which involves long-term patterns of behaviour) is related to vomiting and bulimia, then a previous history of these features is likely to be relevant in grouping patients on a basis that has associations with PD, even if they are absent from the recent history. The patient’s description of binge eating had to be judged by the author to involve and abnormally large amount of food to qualify for the diagnosis of bulimia. A history of vomiting was identified if the subject had induced vomiting on more than one occasion for the purpose of weight control. Statistics
The statistical analysis was carried out with the SPSSjPC program (40). Comparisons between means were made with t-tests (2-tailed) or with Bonferroni t-tests to allow for multiple comparisons. For x = the number of related t-tests, the significancelevel yielded by the t-test needed to be 0.05 divided by x to be considered significant at the 0.05 level (41). The pooled-variance t-test was used unless an F-test indicated significant (P
