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Rapid Response to Cognitive Behavior Therapy Predicts Treatment Outcome in Patients With Irritable Bowel Syndrome

Published:February 18, 2010DOI:https://doi.org/10.1016/j.cgh.2010.02.007

      Background & Aims

      Cognitive behavior therapy (CBT) is an empirically validated treatment for irritable bowel syndrome (IBS), yet it is unclear for whom and under what circumstances it is most effective. We investigated whether patients who achieved a positive response soon after CBT onset (by week 4), termed rapid responders (RRs), maintain treatment gains compared with non–rapid responders. We also characterized the psychosocial profile of RRs on clinically relevant variables (eg, health status, IBS symptom severity, distress).

      Methods

      The study included 71 individuals (age, 18–70 y) whose IBS symptoms were consistent with Rome II criteria and were of at least moderate severity. Patients were assigned randomly to undergo a wait list control; 10 weekly 1-hour sessions of CBT; or four 1-hour CBT sessions over 10 weeks. RRs were classified as patients who reported adequate relief of pain, adequate relief of bowel symptoms, and a decrease in total IBS severity scores of 50 or greater by week 4.

      Results

      Of patients undergoing CBT, 30% were RRs; 90% to 95% of the RRs maintained gains at the immediate and 3-month follow-up examinations. Although the RRs reported more severe IBS symptoms at baseline, they achieved more substantial, sustained IBS symptom reduction than non–rapid responders. Both dosages of CBT had comparable rates of RR.

      Conclusions

      A significant proportion of IBS patients treated with CBT have a positive response within 4 weeks of treatment; these patients are more likely to maintain treatment gains than patients without a rapid response. A rapid response is not contingent on the amount of face-to-face contact with a clinician.

      Keywords

      Abbreviations used in this paper:

      ANOVA (analysis of variance), BSI (Brief Symptom Inventory), CBT (cognitive behavioral therapy), GI (gastrointestinal), IBS (irritable bowel syndrome), IBS-LOC (irritable bowel syndrome–specific locus of control), IBS-SE (Irritable Bowel Syndrome Management Self Efficacy Scale), IBSSS (Irritable Bowel Syndrome Severity Scale), MANOVA (multivariate analysis of variance), MC-CBT (minimal contact cognitive behavioral therapy), NRR (non–rapid responder), QOL (quality of life), RR (rapid responder), S-CBT (standard cognitive behavioral therapy), TSRQ-IBS (Treatment Self-Regulation Questionnaire–Irritable Bowel Syndrome)
      See related article, Blankstein U et al, on page 1783 in Gastroenterology.
      Irritable bowel syndrome (IBS) is a common, chronic, often disabling gastrointestinal (GI) disorder best understood from the perspective of the biopsychosocial model.
      • Drossman D.A.
      Presidential address: gastrointestinal illness and the biopsychosocial model.
      Central to this conceptualization is recognition that IBS symptoms (abdominal pain/discomfort with altered defecation) are clinical manifestations of dysregulation in the bidirectional neural connections linking the gut to the cognitive and emotional centers in the brain (ie, brain–gut axis
      • Ballenger J.C.
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      Consensus statement on depression, anxiety, and functional gastrointestinal disorders.
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      Irritable bowel syndrome: a model of the brain-gut interactions.
      ). Although alterations at any level of the brain–gut axis influence motility, visceral sensation, and intestinal secretion,
      • Wood J.D.
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      • Andrews P.L.
      Fundamentals of neurogastroenterology.
      multiple lines of evidence highlight the importance of central processes in the perception and maintenance of symptoms, particularly in more severely affected patients.
      One measure of the influence of central factors on IBS comes from outcome research testing the efficacy of psychosocial therapies. These data, as summarized in a recent meta-analysis,
      • Lackner J.M.
      • Morley S.
      • Dowzer C.
      • et al.
      Psychological treatments for irritable bowel syndrome: a systematic review and meta-analysis.
      suggest that psychological treatments as a whole are at least moderately effective in reducing IBS symptoms. Although there were not enough data to establish the relative superiority of any one type of psychological treatment, 14 of 17 trials in the meta-analysis featured cognitive behavior therapy (CBT). The therapeutic value of CBT was echoed in a recently published New England Journal of Medicine narrative review
      • Mayer E.A.
      Clinical practice Irritable bowel syndrome.
      that identified CBT as one of the few empirically validated treatments for IBS.
      These data are important because dietary and medical treatments designed to modulate intestinal motility and decrease visceral sensitivity have proven largely unsatisfactory for the full range of IBS symptoms. Notwithstanding impressive data supporting CBT for IBS, a sizable proportion (20%–35%) of patients who undergo CBT either do not respond or do not respond well enough for symptom change to represent clinically meaningful improvement.
      • Drossman D.A.
      • Toner B.B.
      • Whitehead W.E.
      • et al.
      Cognitive-behavioral therapy versus education and desipramine versus placebo for moderate to severe functional bowel disorders.
      • Blanchard E.B.
      • Lackner J.M.
      • Gusmano R.
      • et al.
      Prediction of treatment outcome among patients with irritable bowel syndrome treated with group cognitive therapy.
      Identifying variables that specify for whom a treatment works or under what conditions a treatment is effective has the potential to improve clinical decision making, health care policy, and patient care. If negative prognostic indicators are identified, it may be possible to engineer protocol changes in a way that optimizes outcome for patients at highest risk for treatment failure. Specifying prognostic variables would help us move closer to answering a fundamental question that should guide all efficacy research: what treatment, by whom, is most effective for which individual and for what symptoms.
      • Paul G.
      Strategy of outcome research in psychotherapy.
      Few studies formally have examined potential modifiers (predictors, moderators, variables that alter the strength or direction of a relationship) of CBT response in IBS. The few studies that have examined predictors have focused on variables conveniently collected during baseline assessment such as demographic variables (eg, sex), distress (depression, anxiety), and clinical characteristics (eg, symptom severity, predominant bowel habit). These variables exert such a modest influence on outcome that “other variables … must be responsible for change in the actual GI symptoms of IBS.”
      • Blanchard E.B.
      • Lackner J.M.
      • Gusmano R.
      • et al.
      Prediction of treatment outcome among patients with irritable bowel syndrome treated with group cognitive therapy.
      There is a growing belief that treatment effects are not defined strictly by the personal characteristics patients bring to treatment but rather are shaped by factors that occur during the course of treatment.
      • Breslin F.C.
      • Sobell M.B.
      • Sobell L.C.
      • et al.
      Toward a stepped care approach to treating problem drinkers: the predictive utility of within-treatment variables and therapist prognostic ratings.
      • Wadden T.A.
      • Letizia K.A.
      Predictors of attrition and weight loss in patients treated by moderate and severe caloric restriction.
      • Agras W.S.
      • Walsh T.
      • Fairburn C.G.
      • et al.
      A multicenter comparison of cognitive-behavioral therapy and interpersonal psychotherapy for bulimia nervosa.
      • Ilardi S.S.
      • Craighead W.E.
      The role of nonspecific in cognitive-behavior therapy for depression.
      One such predictor is the rapidity of treatment response. Contrary to the commonly held view that patients undergoing psychological therapies improve gradually and incrementally over time and therefore require extended treatment to show meaningful change,
      • Drossman D.A.
      • Toner B.B.
      • Whitehead W.E.
      • et al.
      Cognitive-behavioral therapy versus education and desipramine versus placebo for moderate to severe functional bowel disorders.
      • Elkin I.
      • Pilkonis P.A.
      • Docherty J.P.
      • et al.
      Conceptual and methodological issues in comparative studies of psychotherapy and pharmacotherapy, II: nature and timing of treatment effects.
      a wealth of research over the past 2 decades shows that a significant proportion of patients undergoing CBT for a variety of conditions achieves rapid, substantial, and sustained symptom improvements relatively early in treatment (eg, first 4 weeks).
      • Ilardi S.S.
      • Craighead W.E.
      The role of nonspecific in cognitive-behavior therapy for depression.
      The significance of the rapid-response phenomenon lies partly in its prognostic value. Rapid responders (RRs) are significantly more likely to do better at the end of the acute phase of CBT and long-term follow-up evaluation than non–rapid responders (NRRs).
      • Fennell M.J.V.
      • Teasdale J.D.
      Cognitive therapy for depression: individual differences and the process of change.
      Prognostic information obtained before treatment has run its course has the potential to provide clinicians guidance for determining which patients are likely to respond to treatment and when treatments are working or not working.
      • Wilson G.T.
      Rapid response to cognitive behavior therapy.
      Patients who quickly achieve treatment gains (eg, IBS symptom relief) may be spared the cost and inconvenience of follow-up care of marginal therapeutic value. This scenario may lead to the development of self-guided treatments based on multimedia technology (eg, web, DVD, smartphone) and free up a dearth of trained clinicians to focus on more severely affected patients. Conversely, patients who do not respond within a set number of sessions early on could be identified and triaged immediately or stepped-up to potentially more powerful treatment(s) (eg, combining CBT with pharmacotherapy) rather than bearing the cost, demoralization, and frustration that comes with treatment failure from insufficient unimodal therapies. The phenomenon of rapid response is of interest not only to behavioral researchers. Once the most powerful ingredients of behavioral treatments are distilled, biologically oriented clinical researchers in academia and industry can harness the clinical benefit of CBT to maximize the therapeutic value of pharmacologic treatments.
      With the assumption that the rapid-response phenomenon observed in other CBT interventions would apply to IBS, we predicted that a significant proportion (25%–40%) of IBS patients undergoing CBT would achieve a positive response early in treatment (by week 4). We also predicted that early responders would be more likely to maintain their treatment gains than NRRs at the end of the acute treatment phase and through follow-up evaluation 3 months after the end of treatment. A secondary goal was to characterize the psychosocial profile of RRs on clinically relevant cognitive processes.

      Patients and Methods

       Study Design

      This study was a secondary analysis of a single-site, 3-arm, randomized controlled trial pitting CBT delivered in either 4- or 10-session doses against a waiting list control. Both CBT versions were comparably efficacious and superior to waiting list control in improving IBS symptoms, reducing quality-of-life impairment, and delivering adequate relief from both pain and bowel symptoms. Additional details about the results and design of this study (eg, CONSORT statement) are published elsewhere.
      • Lackner J.M.
      • Jaccard J.
      • Krasner S.S.
      • et al.
      Self-administered cognitive behavior therapy for moderate to severe irritable bowel syndrome: clinical efficacy, tolerability, feasibility.

       Participants

      Participants were 75 adults between the ages of 18 and 70 years who were diagnosed with IBS according to Rome II criteria without comorbid GI disease. Four subjects were excluded because their data were not suitable for analysis. A detailed description of eligibility criteria can be found in our original report.
      • Lackner J.M.
      • Jaccard J.
      • Krasner S.S.
      • et al.
      Self-administered cognitive behavior therapy for moderate to severe irritable bowel syndrome: clinical efficacy, tolerability, feasibility.

       Treatment Conditions

      CBT was delivered in 2 doses: either 10 weekly 1-hour sessions (standard CBT [S-CBT]) or four 1-hour sessions over 10 weeks (minimal contact CBT [MC-CBT]). MC-CBT covers the same range of procedures featured in S-CBT but largely is patient-administered and relies extensively on self-study materials.
      • Lackner J.M.
      Controlling IBS the drug-free way: a 10-step plan for symptom relief.
      The passive control subjects were wait listed (ie, placed on a 10-week delayed treatment wait list, during which time they monitored the severity of GI symptoms on a daily basis).

       Measures

       Efficacy end points

      Participants completed 2 binary (yes/no) adequate relief measures (adequate of relief of pain, other IBS symptoms such as diarrhea, constipation, bloating) and the Irritable Bowel Syndrome Severity Scale
      • Francis C.Y.
      • Morris J.
      • Whorwell P.J.
      The irritable bowel severity scoring system: a simple method of monitoring irritable bowel syndrome and its progress.
      (IBSSS). The IBSSS requires the patient to evaluate 5 items on 100-point scales: severity of abdominal pain, frequency of abdominal pain, severity of abdominal distension, dissatisfaction with bowel habits, and interference with quality of life. All 5 components contribute equally to the total score, yielding a range of 0 to 500, in which a higher score indicates a more severe condition.

       Additional measures

      Several other psychometrically validated measures were administered on the same testing schedule as the IBSSS to assess the psychosocial dimension of treatment response. Our selection of measures reflected our interest in the cognitive aspects of IBS that potentially could influence rapidity of treatment response. The 25-item IBS Management Self Efficacy Scale
      • Lackner J.M.
      • Krasner S.S.
      • Holroyd K.
      IBS management self efficacy scale.
      • Lackner J.M.
      • Krasner S.S.
      • Quigley B.
      • et al.
      Cognitive behavior therapy improves severity of IBS symptoms by modifying patients' illness beliefs: results of a randomized clinical trial.
      (IBS-SE) measures patient confidence in his or her ability to control and manage IBS episodes using a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree). The IBS-Specific Locus of Control (IBS-LOC
      • Lackner J.M.
      • Holroyd K.
      Locus of control scale-IBS version (a self report measure for assessing perceived control in IBS patients).
      • Lackner J.M.
      • Jaccard J.
      • Krasner S.S.
      • et al.
      Self-administered cognitive behavior therapy for moderate to severe irritable bowel syndrome: clinical efficacy, tolerability, feasibility.
      ) scale is a 33-item scale (5 point scale: 1 = strongly disagree, 5 = strongly agree) that measures patient beliefs that IBS symptoms are controlled internally, controlled by health care professionals, or dictated by chance, respectively. The IBS version of the Treatment Self-Regulation Questionnaire
      • Lackner J.M.
      • Deci E.L.
      Treatment self regulation questionnaire for IBS (a self report questionnaire of treatment motivation specific to IBS patients).
      (TSRQ-IBS) assesses the reasons for adopting behavioral strategies to manage IBS symptoms. Patterned after previous self-regulation questionnaires
      • Ryan R.M.
      • Connell J.P.
      Perceived locus of causality and internalization: examining reasons for acting in two domains.
      that focus on a person's motivation for engaging in a targeted health behavior (eg, control of glucose level), the TSRQ-IBS focuses on motivation for learning behavioral self-management strategies for IBS. The TSRQ-IBS presents 15 sentence stems (eg, “The reason I would learn self-management skills for managing IBS symptoms is …”) that are followed by items that represent either autonomy-oriented motivation (“I feel that I want to take responsibility for my own stomach problems”), control-oriented motivation (“Because I feel pressure from others to do so”), or amotivation (“I really do not know why”) motivation. Each reason is rated on a 5-point scale ranging from not true at all to very true. The Irritable Bowel Quality of Life (IBS-QOL
      • Patrick D.L.
      • Drossman D.A.
      • Frederick I.O.
      • et al.
      Quality of life in persons with irritable bowel syndrome: development and validation of a new measure.
      ) is a 34-item, disease-specific health-related QOL measure assessing the subjective well-being of patients with IBS. Psychological distress was measured using the Global Severity Index of the Brief Symptom Inventory (BSI).
      • Derogatis L.R.
      Brief symptom inventory.
      All measures were administered at baseline, at week 4 of treatment, 2 weeks after treatment ended (week 12), and at the 3-month follow-up evaluation with the exception of adequate relief measures, which obviously were not completed at baseline.

       Criteria for Treatment Response

      Based on Rome guidelines
      • Irvine E.J.
      • Whitehead W.E.
      • Chey W.D.
      • et al.
      Design of treatment trials for functional gastrointestinal disorders.
      we classified treatment responders as patients who (1) provided an affirmative response to both AR questions (pain and bowel habits), and (2) showed a decrease in their total IBSSS score of 50 points or more from baseline. Previous research defines a reduction of 50 points or more on the IBSSS as “clinically important.”
      • Francis C.Y.
      • Morris J.
      • Whorwell P.J.
      The irritable bowel severity scoring system: a simple method of monitoring irritable bowel syndrome and its progress.
      Patients who met these 2 criteria for treatment responders at week 4 were classified as RRs. Patients who did not meet both of these criteria at week 12 were classified as NRRs.

       Statistical Analyses

      We used an intent-to-treat approach to examine the data. A last observation carried forward technique was used to handle missing data. The technique
      • Lachic J.M.
      Statistical considerations in the intent-to-treat principle.
      • Gross D.
      • Fogg L.
      A critical analysis of the intent-to-treat principle in prevention research.
      of replacing participant's missing values after drop-out with the last available measurement is a widely accepted strategy for dealing with missing data caused by attrition in IBS clinical trials.
      • Lembo T.
      • Wright R.A.
      • Bagby B.
      • et al.
      Alosetron controls bowel urgency and provides global symptom improvement in women with diarrhea-predominant irritable bowel syndrome.
      • Drossman D.A.
      • Chey W.D.
      • Johanson J.F.
      • et al.
      Clinical trial: lubiprostone in patients with constipation-associated irritable bowel syndrome—results of two randomized, placebo-controlled studies.
      • Camilleri M.
      • Chey W.Y.
      • Mayer E.A.
      • et al.
      A randomized controlled clinical trial of the serotonin type 3 receptor antagonist alosetron in women with diarrhea-predominant irritable bowel syndrome.
      One-way analyses of variance (ANOVAs) and chi-square analyses were used to assess differences between responder type on demographic and pretreatment variables. Repeated-measures (multivariate ANOVAs [MANOVAs]) (RR status × time) were conducted for the IBS-LOC subscales, and the IBS-SE and TSRQ-IBS subscales. We grouped the IBS-SE and the TSRQ-IBS together because of their theoretical and statistical relationships. MANOVAs were conducted to reduce the possibility of type II errors. If the MANOVAs were significant, post hoc ANOVAs were conducted to explore differences between the groups on each measure at each phase of administration, and repeated-measures ANOVAs examined within-group differences over time, with each controlling for multiple comparisons.

      Results

       Characteristics of Rapid Responders

      Demographic characteristics and pretreatment psychological distress of the RR and the NRR are shown in Table 1. RRs did not differ significantly from NRRs on psychological distress or demographic characteristics (age, education level, marital status, or ethnicity) with the exception of sex (females who comprised a large proportion of the sample were more likely to be RRs). Also, RRs rated their pretreatment symptoms as more severe (IBSSS: RR, 330.3; NRR, 274.6; P < .01; Table 2).
      Table 1Baseline Characteristics of Study Sample
      RRs (N = 21)NRRs (N = 50)
      Age (SD), y47.3 (17.7)46.0 (16.2)
      % Female
      P < .05.
      10080
      Education
       Some high school11
       High school graduate24
       Some college48
       College degree817
       Some postgraduate14
       Master's degree511
       Doctoral degree05
      Marital status
       Single512
       Married826
       Divorced410
       Widowed20
       Cohabitating22
      Ethnicity
       Caucasian2047
       Asian American01
       African American11
       Hispanic01
      BSI
       Anxiety57.9 (9.2)56.6 (10.3)
       Depression55.8 (10.8)55.3 (9.6)
       Somatization59.3 (7.8)59.3 (9.7)
       Global distress60.0 (8.7)58.1 (9.3)
      a P < .05.
      Table 2RRs and NRRs Over Time on Key Clinical Variables
      PretreatmentPosttreatment3 months' posttreatment
      RR

      M (SD)
      NRR

      M (SD)
      RR

      M (SD)
      NRR

      M (SD)
      RR

      M (SD)
      NRR

      M (SD)
      IBS-LOC
       Internal36.7 (10.6)a138.6 (9.8)c147.6 (7.5)b242.3 (10.4)d345.7 (8.4)b441.9 (10.5)d4
       Chance33.4 (9.4)a132.2 (8.5)c118.8 (7.1)b225.2 (11.4)d319.1 (8.2)b225.8 (10.4)d3
       Health care26.1 (6.9)a129.1 (7.6)c122.3 (9.2)b225.3 (8.6)d220.7 (8.4)b325.8 (8.4)d4
      IBS-SE96.5 (25.0)a1100.2 (25.0)c1152.5 (18.1)b2131.7 (33.1)d3146.7 (19.9)b2127.8 (32.7)d3
      TSRQ-IBS
       Autonomous39.4 (2.6)a135.7 (6.4)c239.3 (3.6)a337.8 (5.6)c339.4 (4.1)a437.1 (5.8)c4
       Control14.6 (6.8)a113.3 (6.6)c116.3 (8.9)a313.1 (6.7)c315.6 (9.1)a413.5 (7.1)c4
       Amotivation3.5 (1.4)a15.4 (3.5)c25.1 (3.1)b35.4 (3.8)c35.1 (3.0)b45.2 (3.6)c4
      IBS-QOL49.0 (21.1)a160.6 (17.7)c269.4 (16.2)b273.3 (17.7)c271.0 (17.5)b273.0 (18.2)c2
      IBS-SSS329.9 (63.5)a1278.4 (79.9)c2127.2 (58.5)b3215.2 (96.3)d4131.7 (66.4)b3214.1 (97.4)d4
      NOTE. Within-group values with similar alphabetic superscripts for each measure are statistically equal. Between-group values with similar numeric superscripts are statistically equal at each phase of administration.
      SD, standard deviation.

       Rapid Responders Across the Sample Over Time

      Of the 71 patients randomized to CBT, 21 (29.6%) showed a rapid response by the fourth week of the 10-week treatment phase. Week 4 corresponded to clinic session 2 of treatment for patients assigned to MC-CBT and clinic session 4 for patients undergoing S-CBT. The average reduction of IBSSS total score at week 4 was 132.5 (standard deviation, 53.0) points for RRs and 19.7 (standard deviation, 69.7) points for NRRs. The 2 CBT conditions did not differ significantly in the proportion of participants who met criteria for a rapid response at week 4. Thirty-one percent of the S-CBT patients and 27% of the MC CBT patients met criteria for RR at week 4.

       Global Irritable Bowel Syndrome Symptom Relief

      At week 12 (2 weeks after the end of treatment), 37 of the 71 (52.1%) participants met the criteria for treatment responder. Of the 21 RRs, 19 (90.5%) were acute treatment responders. Of the 50 NRRs, 18 (36.0%) were treatment responders. RRs reported significantly less symptom severity on the IBSSS than NRRs (127.2 vs 215.2; P < .001) even though they had more severe symptoms at baseline (IBSSS scores: RR, 330.3; NRR, 274.6). The magnitude of the difference between RRs and NRRs at posttreatment well exceeded the 50-point reduction index regarded as a sign of clinical improvement.
      • Francis C.Y.
      • Morris J.
      • Whorwell P.J.
      The irritable bowel severity scoring system: a simple method of monitoring irritable bowel syndrome and its progress.
      At the 3-month posttreatment follow-up evaluation, 34 of the 71 (47.9%) participants maintained their status as treatment responders as defined by the same criteria used at 4 weeks and immediately posttreatment. There was a significant difference between RRs and NRRs with 20 of 21 (95.2%) RRs and 14 of 50 (28%) NRRs (χ2, P < .001) maintaining treatment gains at 3 months' posttreatment. RRs continued to report significantly less symptom severity on the IBSSS (131.7 vs 214.1; P < .01).

       Locus of Control–Irritable Bowel Syndrome

      A repeated-measures MANOVA on the IBS-LOC subscales revealed a significant interaction effect for group × time (F [6, 64] = 5.33; P < .001). For the individual subscales of the IBS-LOC, significant interactions were found for internal (F [2, 138] = 10.22; P < .001) and chance (F [2, 138] = 8.50; P < .001), but not for health care, subscales. Repeated-measures ANOVAs revealed that the RR group improved significantly from pretreatment to posttreatment and from pretreatment to the 3-month follow-up evaluation on both the internal (pre-post difference: F = 32.01; P < .001; pre–3-month: F = 26.23; P < .001) and chance (pre-post difference: F 33.21; P < .001; pre–3-month: F = 28.21; P < .001) subscales. There was no significant difference between the posttreatment and 3-month follow-up scores on either scale. Similar results were found for the NRR group (Table 2).
      Tests of simple effects at each assessment period revealed that there were no significant differences between the RR and NRR groups on either the internal or chance LOC subscales at pretreatment. However, the RR group scored significantly better than the NRR group at posttreatment on the internal subscale (F [1, 69] = 4.32; P < .02) and the chance subscale of the IBS LOC scale (F [1, 69] = 5.68; P < .02). These data suggest that RRs had stronger perceptions of internal control and lower perceptions that their symptoms were dictated by chance than NRRs. At 3 months' posttreatment, RRs continued to score better than the NRRs on the chance LOC subscale (F [1, 69] = 6.69; P < .01), but the difference on the internal LOC subscale disappeared.

       Irritable Bowel Syndrome–Self Efficacy and Treatment Self-Regulation (Motivation)

      A repeated-measures MANOVA on the IBS-SE and the TSRQ-IBS subscales revealed a significant interaction effect for group × time (F [8, 60] = 3.13; P < .005), with planned follow-up ANOVAs showing significant interactions for the IBS-SE (F [2, 134] = 6.35; P < .005) and the amotivation subscale of the TSRQ (F [2, 134] = 5.57; P < .005), but not for the autonomous and controlled subscales. Repeated-measures ANOVAs revealed that the RR group improved significantly from pretreatment to posttreatment and the 3-month follow-up evaluation on both the IBS-SE (pre-post: F = 64.31; P < .001; pre–3-month: F = 57.26; P < .001) and amotivation (pre-post: F = 4.03; P < .01; pre–3-month: F = 5.88; P < .01) subscale. There were no significant differences on the autonomous or controlled subscales of the TSRQ, or between the posttreatment and 3-month follow-up scores on the IBS-SE and the amotivation subscale. For the NRR group, the only significant difference over time was from pretreatment to posttreatment and the 3-month follow-up evaluation on the IBS-SE (pre-post: F = 38.31; P < .001; pre–3-month: F = 35.06; P < .001).
      Tests of simple effects at phase of administration revealed that there were significant differences between the RR and NRR groups on the autonomous (F [1, 67] = 6.25; P < .01) and amotivation (F [1, 67] = 5.80; P < .01) subscales of the TSRQ at pretreatment, with RRs reporting more autonomous motivation to learn behavioral self-management skills for IBS than NRRs, and NRRs reporting a greater lack of motivation (amotivation). There were no differences between groups on the IBS-SE or the controlled subscale at pretreatment. Also, there were no differences between groups on any of the TSRQ subscales at posttreatment or at the 3-month follow-up evaluation. However, there were significant differences between groups on the IBS-SE at posttreatment (F [1, 69] = 7.31; P < .01) and at the 3-month follow-up evaluation (F [1, 69] = 6.00; P < .01), with the RR group reporting significantly greater self-efficacy for managing IBS symptoms.

       Irritable Bowel Syndrome–Quality of Life

      For the IBS-QOL, a repeated-measures ANOVA revealed a significant interaction effect for group × time (F [2, 138] = 4.20; P < .01). Post hoc tests showed that the RR group improved significantly from pretreatment to posttreatment (F = 24.71; P < .001) and the 3-month follow-up evaluation (F = 22.08; P < .001), with similar results for the NRR group (Table 2). Tests of simple effects revealed that there was a significant difference between the RR and NRR groups at pretreatment (F [1.69] = 5.71; P < .01), but this difference disappeared at both posttreatment and the 3-month follow-up evaluation.

      Discussion

      Of 71 Rome II–diagnosed IBS patients randomized to CBT, 21 (29.6%) showed a rapid response by the fourth week of treatment (sessions 4 and 2 of the S-SCT and MC-CBT, respectively). RRs were significantly more likely than NRRs to meet criteria for a treatment responder at posttreatment, as outlined by the Rome II committee and to maintain this response at the 3-month follow-up evaluation. We are not inclined to believe the rapidity of response is simply a manifestation of a milder IBS condition. RRs had more severe IBS symptoms and QOL impairment than other patients. We also do not believe that differences in distress accounted for our findings (eg, the notion that patients responded more rapidly because they were less distressed). In fact, RRs did not differ from NRRs on measures of global distress (BSI). Further research is necessary to clarify whether RRs maintain treatment response longer term (eg, 12 months), and, if so, what propels the durability of treatment response.
      Our study highlights patient and treatment factors that may promote rapid response to CBT in this population. With respect to patient factors, we found a strong connection between personal control beliefs and rapid response at interim and follow-up assessment periods. In comparison with NRRs, RRs were more likely to have a high internal locus of control (ie, attribute their symptoms to their own specific behavior), express more confidence in their ability to make specific behavior changes necessary to control IBS symptoms, and have stronger motivation to participate in a self-management program.
      Some might have predicted that the therapist-directed, time-intensive, and highly structured demands of weekly CBT would promote a more rapid response. This prediction dovetails with the dose-effect model of therapy,
      • Howard K.I.
      • Kopta S.M.
      • Krause M.S.
      • et al.
      The dose-effect relationship in psychotherapy.
      which linearly links the magnitude of symptomatic improvement to the amount of treatment (eg, number of therapy sessions) that clients receive. In fact, a similar proportion of patients was classified as RRs regardless of whether they received 1 or 4 hours of face-to-face therapist time. This finding does not comport with the notion that “any benefit [psychologically treated IBS patients] may derive [is] from … the quantity of contact time with the provider”
      American College of Gastroenterology IBS Task Force
      An evidence-based position statement on the management of irritable bowel syndrome.
      and raises an interesting question about whether therapeutic change is owing to relationship factors between the patient and clinician.
      • Chang L.
      • Toner B.
      • Fukudo S.
      • et al.
      Gender, age, society, culture, and the patient's perspective in the functional gastrointestinal disorders.
      • Drossman D.A.
      • Corazziari E.
      • Talley N.J.
      Rome II. The functional gastrointestinal disorders Diagnosis, pathophysiology and treatment: a multinational consensus.
      It is possible that perceptions of a quality therapeutic alliance are a consequence, not a cause, of symptom reduction/relief.
      Conversely, others may predict that the structure and format of a brief self-administered CBT program contains specific features (strict time limit, time alone, elapsed time between clinical visits) that act as “catalytic” triggers for rapid response.
      • Barkham M.
      • Shapiro D.A.
      • Hardy G.E.
      • et al.
      Psychotherapy in two-plus-one sessions: outcomes of a randomized controlled trial of cognitive-behavioral and psychodynamic-interpersonal therapy for subsyndromal depression.
      Neither of these hypotheses was verified, although, as a feasibility study, the present study was not powered to detect between-group differences on rate of rapid response.
      Our data do not suggest that early response is a transient placebo effect because placebo responders typically show an abrupt and early treatment response that decays over time.
      • Quitkin F.M.
      • Rabkin J.G.
      • Stewart J.W.
      • et al.
      Heterogeneity of clinical response during placebo treatment.
      In our study, only 2 subjects reversed a rapid response at posttreatment. The great majority of rapid responders (92.5%) showed an enduring benefit that lasted well over 3 months with little evidence of deterioration. This suggests that rapid response is a relatively robust, clinically meaningful, and enduring clinical phenomenon. Indeed, RRs maintained or continued to improve on the gains made in treatment after termination.
      This study has important health care policy implications that extend well beyond the problem of IBS. The existing health care crisis has crystallized the importance of conducting treatment efficacy research to improve the quality of health care in the United States.
      • Pear R.
      U.S. to study effectiveness of treatments.
      Fundamental to improving health care is conducting outcome research that asks “which treatments work best for which patients.”
      • Pear R.
      U.S. to study effectiveness of treatments.
      Congressional Budget Office
      Research on the comparative effectiveness of medical treatments.
      This has been an elusive goal in part because of the paucity of “hard data” identifying reliable predictors of outcome.
      Congressional Budget Office
      Research on the comparative effectiveness of medical treatments.
      In a recent study by our group,
      • Lackner J.M.
      • Jaccard J.
      • Krasner S.S.
      • et al.
      How does cognitive behavioral therapy for irritable bowel syndrome work? A mediational analysis of a randomized clinical trial.
      we found that pretreatment clinical (eg, predominant bowel type, abuse history, illness, duration, pain severity, psychological distress, and so forth) and demographic variables were for the most part poor predictors of outcome. This was not an isolated finding.
      • Lackner J.M.
      • Jaccard J.
      • Krasner S.S.
      • et al.
      How does cognitive behavioral therapy for irritable bowel syndrome work? A mediational analysis of a randomized clinical trial.
      Researchers would be wise to disband a singular focus on pretreatment factors in favor of a wider one that characterizes the prognostic value of biobehavioral factors that occur during treatment if they want to best position themselves for tackling the question of which treatments works best for which patients. In this respect, this study introduces an innovative conceptual approach that has important implications for tackling some pressing health outcome questions facing us. As clinical researchers, we find gratifying increased attention paid to the importance of treatment efficacy research. As consumers of medical outcome research, we would be more confident that a large federal investment in clinical research will achieve its ambitious goals if it moves beyond solely answering horse race questions of whether treatment X works better than treatment Y to more complex and nuanced questions that bear directly on improving treatment efficacy and efficiency. This answer is not necessarily revealed simply through head-to-head comparisons of treatments. Pressing answers to the question of which treatments work best for which patients calls for both dedicated investment in medical efficacy research as well as the adoption of novel conceptual and methodologic approaches that are beyond the scope of conventional clinical trials.
      This IBS study systematically investigated the role of motivation in IBS treatment using a theory-based measure with sound psychometric properties. Motivation often is regarded as essential to shaping the outcomes of IBS therapies
      • Drossman D.A.
      • Toner B.B.
      • Whitehead W.E.
      • et al.
      Cognitive-behavioral therapy versus education and desipramine versus placebo for moderate to severe functional bowel disorders.
      • Hadley S.K.
      • Gaarder S.M.
      Treatment of irritable bowel syndrome.
      but has received little empiric study from IBS researchers. We found that RRs reported more autonomous motivation to learn behavioral self-management skills for IBS than NRRs, whereas NRRs reported higher levels of amotivation. According to self-determination theory, amotivation (sample TSRQ-IBS item: “I really do not know why I would learn self-management skills for managing IBS symptoms”) occurs in individuals who lack the intention and willingness to engage in a specific behavior. Self-perceptions of incompetence and uncontrollability can account for amotivation, which is linked to behavioral disengagement. The TSRQ-IBS appears to be a psychometrically validated measure of treatment motivation that may be useful in better understanding how motivation impacts IBS treatments whether they are pharmacologic or behavioral in nature.
      Interestingly, rapid response occurred before patients were introduced formally to cognitive techniques (eg, prediction testing, evidence-based logic, formal problem-solving training) that has been characterized
      • Blanchard E.B.
      Irritable bowel syndrome: psychosocial assessment and treatment.
      as the most powerful behavioral strategy for IBS. This invites speculation about what is going on during the first 4 weeks of sessions that fosters such dramatic and enduring change in a sizable subset of patients. It is possible that RRs were especially responsive to relaxation exercises emphasized during 2 of the first 4 weeks of treatment. This interpretation must be weighed against outcome research showing a mixed track record of efficacy for relaxation as a stand-alone behavioral technique for IBS.
      • Keefer L.
      • Blanchard E.B.
      The effects of relaxation response meditation on the symptoms of irritable bowel syndrome: results of a controlled treatment study.
      • Boyce P.M.
      • Talley N.J.
      • Balaam B.
      • et al.
      A randomized controlled trial of cognitive behavior therapy, relaxation training, and routine clinical care for the irritable bowel syndrome.
      Even the studies that support the efficacy of relaxation procedures administered a much longer training schedule (eg, 6 weeks) than our protocol (2 weeks), suggesting that our relaxation procedure, as a stand-alone intervention, was not sufficiently thorough to account for the extent of gains achieved by CBT-treated patients.
      We suspect that symptom monitoring had a stronger hand in expediting early treatment gains. At the first session of both CBT treatments, patients were assigned a rather intensive self-monitoring regimen (see Supplementary Material for self-monitoring record), which included careful tracking of individual GI symptoms, flare-ups, the circumstances in which they occurred, and the antecedent and consequent events such as emotional, cognitive, and physical responses. This is called a functional analysis and was performed on a daily basis through at least week 4. For patients who “spend a lot of time in their heads” worrying about day-to-day events (“if only … ” and “what if … ?”), the task of monitoring situational triggers of IBS flare-ups may force them to step outside of themselves and appraise the environment in a more objective, present-oriented, flexible, and logical (nonthreatening) manner. Self-monitoring may expedite rapid symptom improvement by fostering cognitive changes (awareness, self reflection, and objective appraisal of the relationship between symptom fluctuations and situational influences) critical to self-regulation.
      • Wilson G.T.
      Rapid response to cognitive behavior therapy.
      • Bandura A.
      Social foundations of thought and action: a social cognitive theory.
      • Kanfer F.H.
      Self-regulation: research, issues, and speculation.
      The cognitive demands of conducting a functional analysis go beyond tracking the frequency or severity of daily IBS symptoms and involve monitoring interactive patterns of cognitions, bodily sensations (eg, pain, bloating, urgency), emotions, behaviors, and the external cues that trigger IBS symptoms. Assignment of self-monitoring is a simple, efficient, and potentially beneficial technique that medically oriented IBS practitioners easily could adopt in practices where behavioral medicine treatments are not routinely available.
      There were important limitations to this study. As is the case in many psychotherapy trials, our sample included subjects who volunteered for a behavioral treatment for a medical problem. It is possible that our subjects were more psychologically minded, motivated, and open to a biobehavioral formulation of their condition than those who did not seek psychological treatment for their IBS. Although we did identify differences between RRs and NRRs on key clinical parameters (eg, GI symptom relief/improvement, QOL), our major findings may not necessarily generalize to a broader set of treatment-seeking IBS patients. This trial was designed as a feasibility study and therefore was not powered to detect differences between doses of CBT treatments on rapid response. Whether rapid response is more likely to occur in a brief, home-based or more intensive, clinic-based form of CBT and is unique to CBT (vs common ingredients of therapies including pharmacologic ones
      • Krupnick J.L.
      • Sotsky S.M.
      • Simmens S.
      • et al.
      The role of the therapeutic alliance in psychotherapy and pharmacotherapy outcome: findings in the National Institute of Mental Health Treatment of Depression Collaborative Research Program.
      ) is an important task of a larger randomized controlled trial.

      Acknowledgments

      The authors thank Rebecca Firth and Drs Ann Marie Carosella, Ed Deci, Terry Wilson, and Ken Holroyd for their invaluable help on this study.

      Supplementary material

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