مقایسه فراتشخیصی افزایش رفتار درمانی شناختی (CBT-E) و روان درمانی بین فردی در درمان اختلالات تغذیه ای

Eating disorders may be viewed from a transdiagnostic perspective and there is evidence supporting a transdiagnostic form of cognitive behavior therapy (CBT-E). The aim of the present study was to compare CBT-E with interpersonal psychotherapy (IPT), a leading alternative treatment for adults with an eating disorder. One hundred and thirty patients with any form of eating disorder (body mass index >17.5 to <40.0) were randomized to either CBT-E or IPT. Both treatments involved 20 sessions over 20 weeks followed by a 60-week closed follow-up period. Outcome was measured by independent blinded assessors. Twenty-nine participants (22.3%) did not complete treatment or were withdrawn. At post-treatment 65.5% of the CBT-E participants met criteria for remission compared with 33.3% of the IPT participants (p<0.001). Over follow-up the proportion of participants meeting criteria for remission increased, particularly in the IPT condition, but the CBT-E remission rate remained higher (CBT-E 69.4%, IPT 49.0%; p=0.028). The response to CBT-E was very similar to that observed in an earlier study. The findings indicate that CBT-E is potent treatment for the majority of outpatients with an eating disorder. IPT remains an alternative to CBT-E, but the response is less pronounced and slower to be expressed.

Most studies of mental disorders have focused on specific disorders in isolation. This strategy has been criticised as it complicates the identification of psychopathological processes that operate across disorders (Insel et al., 2010; Insel, 2014) and it makes it difficult to identify treatments that are potentially “transdiagnostic” in their clinical range. In 2003 we suggested that there would be value in viewing eating disorders from a "transdiagnostic" perspective (Fairburn, Cooper, & Shafran, 2003). We proposed that eating disorder psychopathology is maintained by a largely common set of mechanisms, and that treatments capable of addressing these mechanisms should be effective across the various eating disorder presentations. Accordingly, we modified the leading evidence-based treatment for the eating disorders, a cognitive behavioural treatment for bulimia nervosa (CBT-BN) (Fairburn, Marcus, & Wilson, 1993; Fairburn, 1981), to make it suitable for all forms of eating disorder while at the same time we attempted to make it more potent (Cooper & Fairburn, 2011; Fairburn et al., 2003). The resulting treatment, enhanced cognitive behaviour therapy or CBT-E, has been investigated as a treatment for anorexia nervosa (Dalle Grave, Calugi, Conti, Doll, & Fairburn, 2013; Dalle Grave, Calugi, Doll, & Fairburn, 2013; Dalle Grave, Calugi, Ghoch, Conti M, & Fairburn, 2014; Fairburn et al., 2013; Zipfel et al., 2014) and bulimia nervosa (Poulsen et al., 2014; Wonderlich et al., 2014), and in two transdiagnostic samples (Fairburn et al., 2009) that have included cases of bulimia nervosa, binge eating disorder and the various unspecified eating disorder presentations seen in adults (collectively termed “eating disorder not otherwise specified” in DSM-IV (American Psychiatric Association, 1994)). The findings indicate that CBT-E is indeed transdiagnostic in its clinical range, but its relative and absolute effectiveness remain to be established. Neither are clear because there have been differences across the studies in the way that CBT-E has been implemented. The primary aim of the present study was to compare the effects of CBT-E with those of interpersonal psychotherapy (IPT), the leading alternative to cognitive behaviour therapy as a treatment for adult outpatients with an eating disorder. There is evidence supporting the use of IPT in bulimia nervosa (Agras, Walsh, Fairburn, Wilson, & Kraemer, 2000; Fairburn, Jones, Peveler, Hope, & O’Connor, 1993), binge eating disorder (Wilfley et al., 1993, 2002; Wilson, Wilfley, Agras, & Bryson, 2010) and, to a lesser extent, anorexia nervosa (Carter et al., 2011; McIntosh et al., 2005). IPT has not previously been tested in a broad transdiagnostic patient sample nor has it been compared with CBT-E. The second aim was to determine whether the findings of the original and largest study of CBT-E (Fairburn et al., 2009) could be replicated when an equivalent inclusive patient sample was recruited and CBT-E was implemented in the same way.

Results Sample One hundred and thirty eligible participants were recruited and randomized between 2006 and 2011. Their diagnoses were as follows: bulimia nervosa - 53 participants (40.8%); binge eating disorder - 8 participants (6.2%); and “other eating disorder” - 69 participants (53.1%). Sixty-five were randomized to CBT-E and 65 to IPT. The characteristics of the sample are shown in Table 1. Table 1. Characteristics of the sample at baseline. IPT (N = 65) CBT-E (N = 65) All Patients (N = 130) Mean (SD) Mean (SD) Mean (SD) Age (years) 26.8 (8.8) 24.9 (6.4) 25.9 (7.7) N (%) N (%) N (%) Female 63 (96.9) 64 (98.5) 127 (97.7) Ethnicity: White 60 (92.3) 64 (98.5) 124 (95.4) Black British 1 (1.5) 0 (0.0) 1 (0.8) Asian Chinese 0 (0.0) 1 (1.5) 1 (0.8) Asian British 1 (1.5) 0 (0.0) 1 (0.8) Mixed 3 (4.6) 0 (0.0) 3 (2.3) Marital Status: Single, never married 52 (80.0) 58 (89.2) 110 (84.6) Married or living as such 12 (18.5) 6 (9.2) 18 (13.9) Separated or divorced 1 (1.5) 1 (1.5) 2 (1.5) Occupational Social Class: Higher 18 (27.7) 8 (12.3) 26 (20.0) Intermediate 5 (7.7) 9 (13.9) 14 (10.8) Lower 10 (15.4) 11 (16.9) 21 (16.2) Unclassifiable 2 (3.1) 2 (3.1) 4 (3.1) Student 30 (46.2) 35 (53.9) 65 (50.0) DSM-IV Eating Disorder Status: Bulimia nervosa 28 (43.1) 25 (38.5) 53 (40.8) Binge eating disorder 4 (6.2) 4 (6.2) 8 (6.2) Other eating disorder 33 (50.8) 36 (55.4) 69 (53.1) History of anorexia nervosa 15 (23.8) 21 (32.8) 36 (28.4) Mean (SD) Mean (SD) Mean (SD) Duration of eating disorder (years) 11.4 (9.6) 8.4 (7.3) 9.9 (8.6) Lowest adult BMI (kg/m2) 19.3 (2.9) 18.9 (2.8) 19.1 (2.9) Highest adult BMI (kg/m2) 26.6 (5.6) 26.2 (5.4) 26.4 (5.5) N (%) N (%) N (%) Current Comorbid Diagnoses (SCID): Major depressive episode 6 (9.2) 9 (13.9) 15 (11.5) Any anxiety disorder 15 (23.1) 14 (21.5) 29 (22.3) Substance abuse 7 (10.8) 2 (3.1) 9 (6.9) Any Axis 1 disorder 25 (38.5) 22 (34.4) 47 (36.4) Need for psychotropic medication 27 (41.5) 30 (46.2) 57 (43.9) BMI - Body mass index; SCID - Structured Clinical Interview for DSM-IV Axis I Disorders (First et al., 1997). Missing values - There were 2 missing values for history of anorexia nervosa (IPT: 1 missing; CBT: 1 missing) and 1 missing value for any axis I disorder (IPT: 0 missing; CBT: 1 missing). The denominator for percentages is the number of non-missing values. Table options Suitability, Expectancy, Therapy Quality and Attrition The ratings of treatment expectancy were high and did not differ between the two treatments (expectancy, mean and SD - IPT 66.1, 18.6; CBT-E 68.1, 20.5). The same was true of treatment suitability (beginning, mean and SD - IPT 69.2, 18.7; CBT-E 76.6, 19.7; end, mean and SD - IPT 75.5, 21.3; CBT-E 78.2, 24.4). The ratings of treatment fidelity were also high with over two-thirds of the sessions in both treatments being rated as “excellent” (i.e., ratings of 6 or 7 on the 1 to 7 point rating scale). Twenty-nine participants (22.3%) did not complete all 20 sessions of treatment or were withdrawn because of lack of response. The non-completion figures by diagnosis were as follows: bulimia nervosa - 32.1% (17/53); binge eating disorder - 0% (0/8); other eating disorder - 17.4% (12/69). Relative Effects of CBT-E and IPT At Post-treatment At post-treatment the levels of eating disorder and general psychopathology had decreased in both treatment conditions but the changes were significantly greater among the CBT-E participants (see Table 2 and Figure 2). The observed proportion of CBT-E participants in remission (i.e., a global EDE score below 1.74) was almost twice that of those who received IPT (CBT-E - 38/58, 65.5%; IPT - 20/60, 33.3%; adjusted OR 8.8; 95% CI 2.6 to 29.5; p<0.001; see Table 3). Almost half of the CBT-E participants (44.8%, 26/58) reported no binge eating, vomiting or laxative misuse at the end of treatment compared with 21.7% (13/60) in the IPT condition (adjusted OR 6.7; 95% CI 1.9 to 23.6; p=0.003). Table 2. Main clinical features at baseline, post-treatment and at 60-week post-treatment follow-up. Baseline Post-treatment 60-week follow-up IPT (N = 65) CBT (N = 65) IPT (N = 60) CBT (N = 58) IPT (N = 49) CBT (N = 49) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Body mass index (kg/m2) 22.8 (4.2) 22.9 (4.4) 23.6 (4.5) 23.5 (4.1) 24.8 (5.1) 24.1 (4.8) Eating disorder psychopathology (EDE) Global score 3.52 (1.05) 3.59 (1.01) 2.37 (1.25) 1.57 (1.25) 1.83 (1.28) 1.51 (1.20) Dietary restraint 3.70 (1.32) 3.71 (1.09) 2.46 (1.61) 1.08 (1.35) 1.71 (1.53) 1.32 (1.53) Eating concern 2.86 (1.11) 2.81 (1.27) 1.83 (1.40) 1.12 (1.21) 1.24 (1.23) 0.97 (1.09) Shape concern 4.03 (1.32) 4.08 (1.38) 2.53 (1.34) 1.99 (1.43) 2.30 (1.57) 1.98 (1.48) Weight concern 3.47 (1.51) 3.77 (1.31) 2.67 (1.65) 2.09 (1.67) 2.08 (1.60) 1.78 (1.41) Other features Secondary impairment (CIA) 30.0 (8.3) 30.5 (8.6) 19.6 (12.4) 13.9 (10.4) 12.6 (10.8) 12.4 (12.1) Depressive features (BDI) 22.8 (10.9) 21.2 (10.8) 14.0 (12.3) 11.8 (11.0) 11.8 (12.6) 12.7 (11.8) N (%) N (%) N (%) N (%) N (%) N (%) EDE global score < 1 SD above the community mean (<1.74) 4 (6.2) 2 (3.1) 20 (33.3) 38 (65.5) 24 (49.0) 34 (69.4) Eating disorder behaviour (EDE) Objective bulimic episodes >1 51 (78.5) 54 (83.1) 38 (63.3) 25 (43.1) 20 (40.8) 19 (38.8) Self-induced vomiting >1 42 (64.6) 41 (63.1) 31 (51.7) 22 (37.9) 19 (38.8) 19 (38.8) Laxative-taking >1 17 (26.2) 7 (10.8) 12 (20.0) 1 (1.7) 5 (10.2) 1 (2.0) Absence of all of the above 8 (12.3) 6 (9.2) 13 (21.7) 26 (44.8) 23 (46.9) 22 (44.9) Cessation of binge eating and purging if present at baseline (N, %) - - - - 7/52 (13.5) 22/53 (41.5) 16/41 (39.0) 18/45 (40.0) Median (IQR) Median (IQR) Median (IQR) Median (IQR) Median (IQR) Median (IQR) Objective bulimic episodes (N) 14 (3, 28) 11 (4, 28) 7 (0, 18) 0 (0, 5) 0 (0, 4) 0 (0, 2) Self-induced vomiting (N) 14 (0, 40) 5 (0, 25) 1.5 (0, 19) 0 (0, 5) 0 (0, 7) 0 (0, 3) Laxative-taking (N) 0 (0, 1) 0 (0, 0) 0 (0, 0) 0 (0, 0) 0 (0, 0) 0 (0, 0) EDE - Eating Disorder Examination (Fairburn et al., 2008); CIA - Clinical Impairment Assessment (Bohn & Fairburn, 2008; Bohn et al., 2008); BDI - Beck Depression Inventory (Beck et al., 1961); BMI - Body mass index. Missing values - Immediately post-treatment there were a further 4 missing values for BMI, CIA and BDI (IPT: 1; CBT: 3). At 60-week post-treatment, there were a further 6 missing values for BMI (IPT: 4; CBT: 2), 14 missing for CIA (IPT: 7; CBT: 7) and 10 missing for BDI (IPT: 4; CBT: 6). Table options Full-size image (29 K) Figure 2. Intent-to-treat remission rates in the present study and the earlier one (Fairburn et al., 2009). Figure options Table 3. Intention-to-treat analysis at post-treatment and at 60-week post-treatment follow-up. Effect estimates for CBT-E vs IPT Post-treatment Effect estimate for CBT-E vs IPT 60-week follow-up Difference (95% CI) p value Difference (95% CI) p value Body mass index (kg/m2) 0.14 (-0.42 to 0.71) 0.621 -0.59 (-1.50 to 0.32) 0.204 Eating disorder psychopathology (EDE) Global score -0.81 (-1.23 to -0.40) <0.001 -0.28 (-0.74 to 0.18) 0.230 Dietary restraint -1.39 (-1.89 to -0.89) <0.001 -0.42 (-0.98 to 0.14) 0.142 Eating concern -0.69 (-1.14 to -0.23) 0.003 -0.23 (-0.68 to 0.21) 0.304 Shape concern -0.54 (-0.99 to -0.08) 0.021 -0.29 (-0.85 to 0.26) 0.303 Weight concern -0.66 (-1.21 to -0.11) 0.019 -0.28 (-0.82 to 0.26) 0.308 Other features Secondary Impairment (CIA) -6.22 (-10.10 to -2.33) 0.002 -1.33 (-5.72 to 3.05) 0.551 Depressive features (BDI) -1.76 (-5.86 to 2.34) 0.399 1.12 (-3.40 to 5.63) 0.628 Odds ratio (95% CI) p value Odds ratio (95% CI) p value EDE severity score < 1 SD above the community mean (<1.74) 8.75 (2.59 to 29.54) <0.001 4.20 (1.17 to 15.14) 0.028 Eating disorder behaviour (EDE) Objective bulimic episodes >1 0.24 (0.08 to 0.75) 0.014 0.80 (0.24 to 2.66) 0.714 Self-induced vomiting >1 0.22 (0.04 to 1.09) 0.064 0.84 (0.15 to 4.79) 0.843 Laxative-taking >1 0.03 (0.00 to 0.54) 0.018 0.11 (0.00 to 2.82) 0.183 Absence of all of the above 6.68 (1.89 to 23.59) 0.003 1.04 (0.29 to 3.67) 0.954 EDE - Eating Disorder Examination (Fairburn et al., 2008); CIA - Clinical Impairment Assessment (Bohn & Fairburn, 2008; Bohn et al., 2008); BDI - Beck Depression Inventory (Beck et al., 1961). Estimated treatment differences are from longitudinal mixed effects linear or logistic regression models which included data from all participants who were randomised (IPT: 65; CBT: 65), account for missing data and repeated measures on individuals over time and adjust for baseline values of the outcome in question. Table options The changes observed were greater among the participants who completed treatment but the relative effects of the two treatments were similar (see supplementary Tables 1 and 2). Three-quarters of those who completed CBT-E were in remission compared with just over a third of those who completed IPT (CBT-E - 36/48, 75.0%; IPT - 20/53, 37.7%; adjusted OR 13.0; 95% CI 3.4 to 49.4; p<0.001; see Table 3). Over the 60-week Post-treatment Follow-up There was high compliance with the 60-week period of post-treatment follow-up with 79.2% (309/390) of the assessments being successfully completed. Few of the participants required additional treatment. Of the 118 participants who were assessed at the end of treatment and then entered follow-up, seven had further treatment at some point in the 60 weeks and a further seven had up to five brief "booster" sessions. The changes observed during treatment were well maintained in the CBT-E condition (see Table 2 and Figure 2). For example, at the end of treatment the mean global EDE score was 1.57 (SD=1.25) and at 60-week follow-up it was 1.51 (SD=1.20). Over the same period the proportion of participants in remission increased slightly from 65.5% (38/58) at the end of treatment to 69.4% (34/49) at 60-week follow-up (see Figure 2). In the IPT condition the level of psychopathology fell over the period of follow-up with the result that many of the post-treatment differences between CBT-E and IPT were no longer statistically significant at 60-week follow-up (e.g. adjusted mean difference in global EDE score -0.28, 95% CI -0.74 to 0.18, p=0.23; see Table 3), an exception being the primary outcome variable of being in remission which remained higher among the CBT-E participants than among those who received IPT (CBT-E - 34/49, 69.4%; IPT - 24/49, 49.0%; adjusted OR: 4.2; 95% CI: 1.2 to 15.1; p=0.028; see Table 3 and Figure 2). The remission rates during the period of follow-up were higher among those who completed treatment but the relative effects of the two treatments remained similar (see supplementary Tables 2 and 3). The proportion of participants in remission at 60-week follow-up was 70.0% (28/40) in the CBT-E condition and 50.0% (23/46) among those who received IPT (adjusted OR 3.8; 95% CI 1.0 to 14.6; p=0.049). Absolute Effects of CBT-E Figure 2 shows the proportion of participants at each assessment point with a global EDE-Q score below 1.74, together with the equivalent data for CBT-E (focused version) from the earlier study (Fairburn et al., 2009) analysed using the statistical approach described above. It can be seen that in both studies the effects of CBT-E were substantial and well maintained. Furthermore, the magnitude of the response to CBT-E was remarkably similar in the two studies; the remission rates at the end of treatment being 67% in study 1 and 66% in study 2, and at 60-week post-treatment follow-up 63% and 69% respectively.