- Email: [email protected]
The heterogeneity of Bulimia Nervosa and its implications for treatment
no??-3YYY,‘Yi $3 N + .w Pergamon Press plc
J,mrnol Prmted
THE
HETEROGENEITY OF BULIMIA NERVOSA ITS IMPLICATIONS FOR TREATMENT
AND
CHRISTOPHERG.FAIRBURN
INTRODUCTION IT WAS in 1979 that the eating disorder bulimia nervosa was first formally described. Since then, it has attracted a considerable amount of clinical and research attention, particularly in the United States and Britain. It is the aim of this article to outline what has been learned about clinical features, development and course of the disorder and to emphasize two points. First, bulimia nervosa affects many aspects of functioning, not merely eating habits; and second, it varies in its characteristics and this variability has important implications for treatment.
DIAGNOSTIC
FEATURES
Between 1979 and 1987 the criteria used to diagnose bulimia nervosa were very different in North America and Britain. These differences largely disappeared in 1987 with the introduction in the United States of the DSM-III-R criteria [l]. These were broadly similar to the more restrictive criteria already in use in Britain [2]. The DSM-III-R criteria are shown in Table I. In essence, the disorder has three key features [3]. First, there is a loss of control over eating which is associated with recurrent episodes of bulimia (items A and B). These episodes of overeating (often referred to as ‘binges’) usually occur in secret and in most, but not all, patients are a source of shame and self-disgust. During typical bulimic episodes food is eaten rapidly with little attention being paid to its taste or texture, but in a minority of patients protracted episodes occur which last many hours. The food eaten usually consists of items patients are attempting to exclude from their diet, the total amount being in the region of 3500-5000 kcals [4-61. However, similar smaller episodes also occur and some otherwise typical patients only have episodes of this type. The frequency of bulimic episodes varies greatly: they may occur many times a day or they may be intermittent. The usual precipitants are either the breaking of self-imposed dietary rules or feelings of depression, anxiety, boredom or loneliness. Between bulimic episodes most, but not all, patients attempt to restrict their food intake. The second key diagnostic feature is the presence of extreme attempts to control shape and weight (item C). These include self-induced vomiting, strict dieting, the misuse of purgatives and diuretics and, in a minority of patients, vigorous exercising. Often these behaviours occur in combination and, like the overeating, their frequency
Wellcome Trust Senior Leclurer. Oxford University Department Oxford OX3 7JX, U.K. Article based upon a paper read at the VIIIth World Congress
of Psychiatry, of Psychiatry,
Warneford Athens
1989.
Hospital,
CHKISTOPHFR G. FAIRURN
4 TAHLLI.-DSM-III-R A.
B. C. D. E.
DIAGNOSTICCKITEK!AFOKBULIMIANERVOSA
Recurrent episodes of hinge eating (rapid consumption of a of time). A feeling of lack of control over eating behaviour during The person regularly engages in either self-induced vomiting or fasting, or vigorous exercise in order to prevent weight A minimum average of two binge eating episodes a week Persistent overconcern with body shape and wright.
large amount
of food in a discrete
the eating binges. use of laxative> or diuretics, pain. for at least three months
period
strict dieting
varies. It has been suggested that there may be important differences in psychopathology between ‘purging’ and ‘non-purging’ patients, the former being those who vomit or take purgatives and the latter being those who just diet [7]. To date the comparisons of the two groups have been unsatisfactory: none has ensured that the subjects fulfil all five criteria for bulimia nervosa, and few have investigated the inlluence of confounding variables. Body weight is a particularly important confounding variable since ‘non-purging’ patients tend to be considerably heavier than those who purge. A characteristic set of’ attitudes to shape and weight is the third key feature of the disorder. These attitudes, or overvalued ideas. are like those found in anorexia nervosa and have been described as ‘a morbid fear of becoming fat’ [I] or in DSM-III-R (item E) as a ‘persistent overconcern with shape and weight’. (~‘learly these attitudes arc extreme forms of widely held views. What tnakes them dysfunctional is their strength and their great personal significance. The essence of this ‘core psychopathology’, at it has been [errned, is that the patients judge their self-worth largely, or even exclusively. in terms of their shape and weight [8]. As,a result they are preoccupied with thoughts about shape and weight, they do their utmost to avoid weight gain or ‘fatness‘. and some strive to be thin. Most features of bulimia nervosa appear to be secondary to these attitudes 191.
The clinical features of bulimia nervosa are more complex and varied than most descriptions imply. In addition to the three key features which define the disorder. and are therefore present in all cases, there are many other features which may, or may not. be present. Perhaps the most prominent are depressive and anxiety qmptoms [IO], These can be severe and disabling: indeed, in one case series the mean level of depressive symptoms was found to be equivalent to that of patients with major depressive disorder [I I]. Social functioning is also often impaired. This is perhaps noi surprising since repeated episodes of secretive overeating preclude many everyday activities. It is striking, however. how well some patients function, especially with respect to their performance at work. This is because patients Mith bulimia ncrvosa tend to be a highly conscientious group, setting themselves demarlding standards which they do their best to meet. As a result some aspects of their funcConing are spared even when others are markedly impaired. There is a subgroup of patients who show a pervasive disturbance in social funcGomng with their entire life being in a state of chaos [l?]. and there is another overlapping group who have problems with ‘impulse control’ [I-i]. Such patients tend to abuse alcohol or drugs. and a small minority mutilate themselves. In North America many such patients are
The heterogeneity
of bulimia
nervosa
and its implications
for treatment
5
classed as having a ‘borderline personality disorder’, but problems of circularity complicate the use of this problematic concept [14]. Like the psychiatric features, the physical features of bulimia nervosa are varied. Perhaps surprisingly, serious physical disturbances are uncommon. Few abnormalities are found on examination and body weight is usually within the normal range. In a small number of cases there is hypertrophy of the salivary glands, particularly the parotid glands, which accounts for some complaints of facial swelling [15, 161. The pathophysiology of the salivary gland enlargement is unclear. In those patients who have vomited frequently for some years there may be erosion of the dental enamel, especially of the lingual surfaces of the teeth [17]. This accounts for some patients’ complaints of toothache. In addition, those patients who induce vomiting by using their fingers to stimulate the gag reflex may have a characteristic distribution of calluses on the dorsum of the hand (Russell’s sign) [2]. Various abnormalities may be found on laboratory testing. In about half the patients there is electrolyte disturbance, the most common abnormalities being hypochloraemia, hypokalaemia, hyponatraemia and an elevated bicarbonate level [IS]. Very occasionally these abnormalities are life-threatening. The electrolyte disturbance is a secondary effect of self-induced vomiting and the misuse of purgatives and diuretics, the nature of the electrolyte disturbance depending on the predominant behaviour. Another abnormality sometimes found on laboratory testing is a raised serum amylase level [19], usually with high levels of both isoenzymes. The explanation for this increase is unclear. In comparison with anorexia nervosa, the endocrine status of these patients has not been extensively studied. Menstrual irregularities are not uncommon, even amongst those patients whose weight is unremarkable [lo]: in most cases the menstrual abnormalities reverse once healthy eating habits have been restored [20]. EPIDEMIOLOGY
The majority of community-based studies have been concerned with the prevalence of the disorder. The populations studied have been mostly those in which bulimia nervosa commonly presents, namely Caucasian females aged between 14 and 40 yr. Their findings are summarized in Table II, the studies being subdivided on the basis of their method of case detection [21]. From Table II it can be seen that the prevalence studies have produced widely divergent findings with the estimated prevalence rate ranging from O-19%. Two factors have contributed to this divergence. One is differences over the diagnostic criteria used, with the earlier American studies employing the 1980 DSM-III criteria [22] whereas the British ones used Russell’s original definition [2]. The former are now viewed as having been overinclusive. Since the introduction in 1987 of the generally accepted DMS-III-R criteria, more consistent findings have emerged. The second explanation for the divergence concerns the research methods used, particularly the method of case detection. Most studies (group 1) have relied exclusively on the subjects’ responses to self-report questionnaires to make diagnoses, a procedure which is not satisfactory since several of the central features of the disorder present major difficulties of definition and interpretation, a good example being ‘bingeeating’. More recent studies (groups 2 and 3) have improved upon this practice by
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-i-HI
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HL’LIMIA
NCKVOSA
MkTHOIX
Group Prevalence Mean Sl) DSM-III bulimia [22] Bulimia nervosa [I, 21
9.0 2.6
OF CASE
I
(“h) Range
4.3
3 I9
I .D
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Group 2 Prevaience (56) Mea11 SI) Range
I .9 I.6
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I.9 ~~
OS
Group 3 Prevalence (“i,) SII Mean Range
I.5 0.‘)
I .o 0.3
13 0 I
making diagnoses on the basis of clinical interviews, in most cases after having screened the sample for potential cases using a self-report questionnaire. The best of these studies (group 3) have included a formal evaluation of the performance of the case-finding instrument. It can be seen from Table II that, as diagnostic criteria have been refined and research methods improved, progressively lower estimates of the prevalence of the disorder have been obtained. The findings of the most sophisticated studies are impressively consistent with bulimia nervosa appearing to have a prevalence rate amongst adolescent and young adult women in the region of 1%. The increasing consensus over the prevalence of bulimia nervosa should not be accepted uncritically. The figure of 1% may be questioned since it is important not to confuse consistency with accuracy: the studies could well be subject to equivalent sources of error [II]. Also, the clinical significance of this prevalence rate is difficult to gauge. The extent to which cases detected in community surveys resemble clinic-based cases is not known since there have been no comparisons of the two groups. Until the psychiatric and physical morbidity of community-based and clinic-based cases have been compared, it would seem reasonable to assume that the cases detected in community surveys are less disturbed. Support for this assumption comes from the finding of the few longitudinal community-based studies that in the majority of cases the eating disorder is transitory rather than persistent [23--261. DEVELOPMENT
AND
COURSE
There has been remarkably little research on the development of bulimia nervosa. The disorder usually starts as ‘normal’ adolescent dieting which become progressively more extreme. As a result body weight falls and, in between a third and a half of cases. diagnostic criteria for anorexia nervosa are eventually met. Then, control over eating breaks down and the extreme dieting becomes interrupted by episodes of overeating. Vomiting, purgatives and diuretics may be used to minimize the effect on weight of the overeating, but eating habits tend to worsen and the lost weight is regained. Gradually the eating disorder becomes entrenched and. after a variable length of time, treatment is sought. Typically patients are in their mid-twenties by the time that they present themselves for help. There are many exceptions to this sequence of events. In some patients overeating is the initial feature and this may result in obesity. In others, obesity occurs at a later stage. In some the disorder is intermittent with periods of reasonably normal functioning, whereas in others it is continuously present, but unstable, with there being marked shifts in eating habits and weight.
The heterogeneity
of bulimia
nervosa
and its implications
for treatment
7
There have been a number of studies of the course of bulimia nervosa following treatment [20,27-40]. Without exception, these have had major shortcomings and so the findings must be regarded as preliminary. What they do indicate is that outcome is varied: some patients make a rapid and complete recovery, some improve but remain symptomatic, whilst in others the eating disorder persists largely unchanged. One of the most serious limitations of these studies has been the tendency to evaluate outcome simply in terms of the frequency of overeating and purging. It is usually not clear whether the patients are continuing to diet nor is it reported whether they retain the overvalued ideas concerning shape and weight. General psychiatric symptoms, social adjustment and substance abuse have also gone largely unassessed. Thus the true clinical state of the patients is difficult to evaluate. There are no factors known to predict outcome: indeed, satisfactory definitions of ‘recovery’, ‘remission’ and ‘relapse’ have yet to be formulated.
DISCUSSION
The main aim of this article has been to highlight two features of bulimia nervosa. The first is that it affects many aspects of functioning and not just eating habits. By definition, patients with bulimia nervosa have both disturbed eating habits and extreme concerns about shape and weight, but in addition most have high levels of general psychiatric symptoms as well as impaired social functioning. Their physical health may also be affected. Therefore, to evaluate the clinical state of patients, many aspects of functioning need to be considered. The importance of this point is illustrated by the finding that certain treatments selectively affect particular facets of the disorder: for example, antidepressant drugs appear to have a prbnounced effect on the frequency of overeating whilst doing little to reduce the intensity of dieting [41,42]. Similarly, our own research has found that whilst interpersonal psychotherapy has a marked effect both on the overeating and general psychiatric symptoms, it is less effective than cognitive behaviour therapy at modifying the attitudes to shape and weight, attempts to diet and frequency of self-induced vomiting [43]. The second point is that bulimia nervosa is not a homogeneous disorder. Whilst by definition all those with the condition have the three key diagnostic features, in other respects they differ markedly. The diagnostic features vary in severity, and the same is true of the associated features which may not even be present. The course of the disorder is also varied. For some it is a transitory condition, whereas for others it persists and is resistant to treatment. This heterogeneity has major clinical implications since there is likely to be great variability in response both to treatment in general and to specific forms of therapy. Some patients may benefit from any form of intervention, whereas others are likely to require treatment of a particular type. No single treatment is going to be the answer to bulimia nervosa: instead, to cater properly for this patient population, a range of treatment options needs to be provided [44]. Acknowlrd~c,menrs-I am grateful to the Wellcome Trust for their support. I am also grateful colleagues Tony Hope, Robert Peveler, Sarah Beglin and Sarah Welch for their helpful comments paper.
to my on the
C~+KISTOP~I~K
G.
FAIHHI,KF;
The heterogeneity 30. 31. 32.
33. 34. 35. 36. 37. 38. 39. 40.
41. 42. 43. 44.
of bulimia
nervosa
and its implications
for treatment
9
NORMAN DK. HERZOG DB, CHAUNCEY S. A one-year outcome study of bulimia: psychological and eatmg symptom changes in a treatment and non-treatment group. Int J Eaf Dis 1986; 5: 47- 57. LACEY JH. Bulimia nervosa. binge-eating, and psychogenic vomiting: a controlled treatment study and long term outcome. Br Mcd J 1983; 286: 1609- 1613. LACEY JH. Bulimia: factors which influence treatment response. In: Proceedings @‘the 15rh European Cmference on Psychosomatic Research (Edited by LACEY JH and STURGEON DA). London: John Libbey & Co. Ltd., 1986. NORMAN DK, HERZOG DB. A 3-year outcome study of normal-weight bulimia: assessment of psychosocial functioning and eating attitudes. P.Tychiar Res 1986; 19: 199-205. BRO~MAN AW, HERZCIC DB. HAMBURG P. Long-term course in 14 bulimic patients treated with psychotherapy. J C/in Psychiar 1988: 49: 157-160. MITCHELL JE. PYLE RL. HA~SUKAMI D. GOFF G. GLOATER D, HARPER J. A 2&5 year follow-up study of patients treated for bulimia. Inr J Eat Dis 1988; 8: 157~-165. MITCHELL JE, DAVIS L, GOFF G. The process of relapse in patients with bulimia. In/ J Eat Dis 1985; 4: 457463. FREEMANRJ. BEACH B. DAVIS R. SOLYOML. The prediction of relapse in bulimia nervosa. J P.c,whia/ Res 1985; 19: 349-353. Hsu LKG. SOBKIEWICZTA. Bulimia nervosa: a four to six-year follow-up study. Psycho/ Mrd 1989; 19: 1035-1038. ABRAHAM SF, MYRA M, LLEWELLYN-JONTSD. Bulimia: a study of outcome. Inr J Ear Di.7 1983: 2: 175-180. ABRAHAM SF, MIRA M, RICHARDS L. ROLFE J. Long-term follow up of bulimia nervosa patients. In: Eo/in,q Di.wrders and Disordered Earing. (Edited by ABRAHAM SF and LLEWELLYN-JONESD). Sydney: Ashwood House, 1987. ROSSITER EM. AGRAS WS, LOS~H M. Changes in self-reported food intake in bulimics as a consequence of antidepressant treatment. In/ J Ear Dis 1988: 7: 779-783. MITCHELL JE, FLFTCHER L. PYLE RL, E~KERT ED, HA~SUKAMI DK, POMEKOYC. The impact of treatment on meal patterns in patients with bulimia nervosa. In/ J Eat Dis 1989; 8: 167 172. FAIRRURN CG. JONES R, PEVELER RC, et al. Three psychological treatments for bulimia nervosa: a comparative trial. Archs Gen Ps.vchiur. (In press). FAIRBURN CG, P~V~LER RC. Buhmia nervosa and a stepped care approach to management. Gut 1990; 31: 1220&1222.
J,mrnol Prmted
THE
HETEROGENEITY OF BULIMIA NERVOSA ITS IMPLICATIONS FOR TREATMENT
AND
CHRISTOPHERG.FAIRBURN
INTRODUCTION IT WAS in 1979 that the eating disorder bulimia nervosa was first formally described. Since then, it has attracted a considerable amount of clinical and research attention, particularly in the United States and Britain. It is the aim of this article to outline what has been learned about clinical features, development and course of the disorder and to emphasize two points. First, bulimia nervosa affects many aspects of functioning, not merely eating habits; and second, it varies in its characteristics and this variability has important implications for treatment.
DIAGNOSTIC
FEATURES
Between 1979 and 1987 the criteria used to diagnose bulimia nervosa were very different in North America and Britain. These differences largely disappeared in 1987 with the introduction in the United States of the DSM-III-R criteria [l]. These were broadly similar to the more restrictive criteria already in use in Britain [2]. The DSM-III-R criteria are shown in Table I. In essence, the disorder has three key features [3]. First, there is a loss of control over eating which is associated with recurrent episodes of bulimia (items A and B). These episodes of overeating (often referred to as ‘binges’) usually occur in secret and in most, but not all, patients are a source of shame and self-disgust. During typical bulimic episodes food is eaten rapidly with little attention being paid to its taste or texture, but in a minority of patients protracted episodes occur which last many hours. The food eaten usually consists of items patients are attempting to exclude from their diet, the total amount being in the region of 3500-5000 kcals [4-61. However, similar smaller episodes also occur and some otherwise typical patients only have episodes of this type. The frequency of bulimic episodes varies greatly: they may occur many times a day or they may be intermittent. The usual precipitants are either the breaking of self-imposed dietary rules or feelings of depression, anxiety, boredom or loneliness. Between bulimic episodes most, but not all, patients attempt to restrict their food intake. The second key diagnostic feature is the presence of extreme attempts to control shape and weight (item C). These include self-induced vomiting, strict dieting, the misuse of purgatives and diuretics and, in a minority of patients, vigorous exercising. Often these behaviours occur in combination and, like the overeating, their frequency
Wellcome Trust Senior Leclurer. Oxford University Department Oxford OX3 7JX, U.K. Article based upon a paper read at the VIIIth World Congress
of Psychiatry, of Psychiatry,
Warneford Athens
1989.
Hospital,
CHKISTOPHFR G. FAIRURN
4 TAHLLI.-DSM-III-R A.
B. C. D. E.
DIAGNOSTICCKITEK!AFOKBULIMIANERVOSA
Recurrent episodes of hinge eating (rapid consumption of a of time). A feeling of lack of control over eating behaviour during The person regularly engages in either self-induced vomiting or fasting, or vigorous exercise in order to prevent weight A minimum average of two binge eating episodes a week Persistent overconcern with body shape and wright.
large amount
of food in a discrete
the eating binges. use of laxative> or diuretics, pain. for at least three months
period
strict dieting
varies. It has been suggested that there may be important differences in psychopathology between ‘purging’ and ‘non-purging’ patients, the former being those who vomit or take purgatives and the latter being those who just diet [7]. To date the comparisons of the two groups have been unsatisfactory: none has ensured that the subjects fulfil all five criteria for bulimia nervosa, and few have investigated the inlluence of confounding variables. Body weight is a particularly important confounding variable since ‘non-purging’ patients tend to be considerably heavier than those who purge. A characteristic set of’ attitudes to shape and weight is the third key feature of the disorder. These attitudes, or overvalued ideas. are like those found in anorexia nervosa and have been described as ‘a morbid fear of becoming fat’ [I] or in DSM-III-R (item E) as a ‘persistent overconcern with shape and weight’. (~‘learly these attitudes arc extreme forms of widely held views. What tnakes them dysfunctional is their strength and their great personal significance. The essence of this ‘core psychopathology’, at it has been [errned, is that the patients judge their self-worth largely, or even exclusively. in terms of their shape and weight [8]. As,a result they are preoccupied with thoughts about shape and weight, they do their utmost to avoid weight gain or ‘fatness‘. and some strive to be thin. Most features of bulimia nervosa appear to be secondary to these attitudes 191.
The clinical features of bulimia nervosa are more complex and varied than most descriptions imply. In addition to the three key features which define the disorder. and are therefore present in all cases, there are many other features which may, or may not. be present. Perhaps the most prominent are depressive and anxiety qmptoms [IO], These can be severe and disabling: indeed, in one case series the mean level of depressive symptoms was found to be equivalent to that of patients with major depressive disorder [I I]. Social functioning is also often impaired. This is perhaps noi surprising since repeated episodes of secretive overeating preclude many everyday activities. It is striking, however. how well some patients function, especially with respect to their performance at work. This is because patients Mith bulimia ncrvosa tend to be a highly conscientious group, setting themselves demarlding standards which they do their best to meet. As a result some aspects of their funcConing are spared even when others are markedly impaired. There is a subgroup of patients who show a pervasive disturbance in social funcGomng with their entire life being in a state of chaos [l?]. and there is another overlapping group who have problems with ‘impulse control’ [I-i]. Such patients tend to abuse alcohol or drugs. and a small minority mutilate themselves. In North America many such patients are
The heterogeneity
of bulimia
nervosa
and its implications
for treatment
5
classed as having a ‘borderline personality disorder’, but problems of circularity complicate the use of this problematic concept [14]. Like the psychiatric features, the physical features of bulimia nervosa are varied. Perhaps surprisingly, serious physical disturbances are uncommon. Few abnormalities are found on examination and body weight is usually within the normal range. In a small number of cases there is hypertrophy of the salivary glands, particularly the parotid glands, which accounts for some complaints of facial swelling [15, 161. The pathophysiology of the salivary gland enlargement is unclear. In those patients who have vomited frequently for some years there may be erosion of the dental enamel, especially of the lingual surfaces of the teeth [17]. This accounts for some patients’ complaints of toothache. In addition, those patients who induce vomiting by using their fingers to stimulate the gag reflex may have a characteristic distribution of calluses on the dorsum of the hand (Russell’s sign) [2]. Various abnormalities may be found on laboratory testing. In about half the patients there is electrolyte disturbance, the most common abnormalities being hypochloraemia, hypokalaemia, hyponatraemia and an elevated bicarbonate level [IS]. Very occasionally these abnormalities are life-threatening. The electrolyte disturbance is a secondary effect of self-induced vomiting and the misuse of purgatives and diuretics, the nature of the electrolyte disturbance depending on the predominant behaviour. Another abnormality sometimes found on laboratory testing is a raised serum amylase level [19], usually with high levels of both isoenzymes. The explanation for this increase is unclear. In comparison with anorexia nervosa, the endocrine status of these patients has not been extensively studied. Menstrual irregularities are not uncommon, even amongst those patients whose weight is unremarkable [lo]: in most cases the menstrual abnormalities reverse once healthy eating habits have been restored [20]. EPIDEMIOLOGY
The majority of community-based studies have been concerned with the prevalence of the disorder. The populations studied have been mostly those in which bulimia nervosa commonly presents, namely Caucasian females aged between 14 and 40 yr. Their findings are summarized in Table II, the studies being subdivided on the basis of their method of case detection [21]. From Table II it can be seen that the prevalence studies have produced widely divergent findings with the estimated prevalence rate ranging from O-19%. Two factors have contributed to this divergence. One is differences over the diagnostic criteria used, with the earlier American studies employing the 1980 DSM-III criteria [22] whereas the British ones used Russell’s original definition [2]. The former are now viewed as having been overinclusive. Since the introduction in 1987 of the generally accepted DMS-III-R criteria, more consistent findings have emerged. The second explanation for the divergence concerns the research methods used, particularly the method of case detection. Most studies (group 1) have relied exclusively on the subjects’ responses to self-report questionnaires to make diagnoses, a procedure which is not satisfactory since several of the central features of the disorder present major difficulties of definition and interpretation, a good example being ‘bingeeating’. More recent studies (groups 2 and 3) have improved upon this practice by
6 -rABLf
C;.
FAIKIWKN
AS
U1:TFKMINt.U
CHKISWPH~K
11.
-i-HI
PKfVALEN(‘t
Ok-
HL’LIMIA
NCKVOSA
MkTHOIX
Group Prevalence Mean Sl) DSM-III bulimia [22] Bulimia nervosa [I, 21
9.0 2.6
OF CASE
I
(“h) Range
4.3
3 I9
I .D
‘4
IX%-ECTION
BY
STUDIt
Group 2 Prevaience (56) Mea11 SI) Range
I .9 I.6
WIN<.
THKEE
I)IFPFKENT
[2 I]
I.9 ~~
OS
Group 3 Prevalence (“i,) SII Mean Range
I.5 0.‘)
I .o 0.3
13 0 I
making diagnoses on the basis of clinical interviews, in most cases after having screened the sample for potential cases using a self-report questionnaire. The best of these studies (group 3) have included a formal evaluation of the performance of the case-finding instrument. It can be seen from Table II that, as diagnostic criteria have been refined and research methods improved, progressively lower estimates of the prevalence of the disorder have been obtained. The findings of the most sophisticated studies are impressively consistent with bulimia nervosa appearing to have a prevalence rate amongst adolescent and young adult women in the region of 1%. The increasing consensus over the prevalence of bulimia nervosa should not be accepted uncritically. The figure of 1% may be questioned since it is important not to confuse consistency with accuracy: the studies could well be subject to equivalent sources of error [II]. Also, the clinical significance of this prevalence rate is difficult to gauge. The extent to which cases detected in community surveys resemble clinic-based cases is not known since there have been no comparisons of the two groups. Until the psychiatric and physical morbidity of community-based and clinic-based cases have been compared, it would seem reasonable to assume that the cases detected in community surveys are less disturbed. Support for this assumption comes from the finding of the few longitudinal community-based studies that in the majority of cases the eating disorder is transitory rather than persistent [23--261. DEVELOPMENT
AND
COURSE
There has been remarkably little research on the development of bulimia nervosa. The disorder usually starts as ‘normal’ adolescent dieting which become progressively more extreme. As a result body weight falls and, in between a third and a half of cases. diagnostic criteria for anorexia nervosa are eventually met. Then, control over eating breaks down and the extreme dieting becomes interrupted by episodes of overeating. Vomiting, purgatives and diuretics may be used to minimize the effect on weight of the overeating, but eating habits tend to worsen and the lost weight is regained. Gradually the eating disorder becomes entrenched and. after a variable length of time, treatment is sought. Typically patients are in their mid-twenties by the time that they present themselves for help. There are many exceptions to this sequence of events. In some patients overeating is the initial feature and this may result in obesity. In others, obesity occurs at a later stage. In some the disorder is intermittent with periods of reasonably normal functioning, whereas in others it is continuously present, but unstable, with there being marked shifts in eating habits and weight.
The heterogeneity
of bulimia
nervosa
and its implications
for treatment
7
There have been a number of studies of the course of bulimia nervosa following treatment [20,27-40]. Without exception, these have had major shortcomings and so the findings must be regarded as preliminary. What they do indicate is that outcome is varied: some patients make a rapid and complete recovery, some improve but remain symptomatic, whilst in others the eating disorder persists largely unchanged. One of the most serious limitations of these studies has been the tendency to evaluate outcome simply in terms of the frequency of overeating and purging. It is usually not clear whether the patients are continuing to diet nor is it reported whether they retain the overvalued ideas concerning shape and weight. General psychiatric symptoms, social adjustment and substance abuse have also gone largely unassessed. Thus the true clinical state of the patients is difficult to evaluate. There are no factors known to predict outcome: indeed, satisfactory definitions of ‘recovery’, ‘remission’ and ‘relapse’ have yet to be formulated.
DISCUSSION
The main aim of this article has been to highlight two features of bulimia nervosa. The first is that it affects many aspects of functioning and not just eating habits. By definition, patients with bulimia nervosa have both disturbed eating habits and extreme concerns about shape and weight, but in addition most have high levels of general psychiatric symptoms as well as impaired social functioning. Their physical health may also be affected. Therefore, to evaluate the clinical state of patients, many aspects of functioning need to be considered. The importance of this point is illustrated by the finding that certain treatments selectively affect particular facets of the disorder: for example, antidepressant drugs appear to have a prbnounced effect on the frequency of overeating whilst doing little to reduce the intensity of dieting [41,42]. Similarly, our own research has found that whilst interpersonal psychotherapy has a marked effect both on the overeating and general psychiatric symptoms, it is less effective than cognitive behaviour therapy at modifying the attitudes to shape and weight, attempts to diet and frequency of self-induced vomiting [43]. The second point is that bulimia nervosa is not a homogeneous disorder. Whilst by definition all those with the condition have the three key diagnostic features, in other respects they differ markedly. The diagnostic features vary in severity, and the same is true of the associated features which may not even be present. The course of the disorder is also varied. For some it is a transitory condition, whereas for others it persists and is resistant to treatment. This heterogeneity has major clinical implications since there is likely to be great variability in response both to treatment in general and to specific forms of therapy. Some patients may benefit from any form of intervention, whereas others are likely to require treatment of a particular type. No single treatment is going to be the answer to bulimia nervosa: instead, to cater properly for this patient population, a range of treatment options needs to be provided [44]. Acknowlrd~c,menrs-I am grateful to the Wellcome Trust for their support. I am also grateful colleagues Tony Hope, Robert Peveler, Sarah Beglin and Sarah Welch for their helpful comments paper.
to my on the
C~+KISTOP~I~K
G.
FAIHHI,KF;
The heterogeneity 30. 31. 32.
33. 34. 35. 36. 37. 38. 39. 40.
41. 42. 43. 44.
of bulimia
nervosa
and its implications
for treatment
9
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