CBT for Chronic Pain: Specific vs Nonspecific Therapeutic Mechanisms

Transcription

1 CBT for Chronic Pain: Specific vs Nonspecific Therapeutic Mechanisms John W. Burns, PhD Rush University Medical Center, Chicago, IL Mark Jensen, PhD, University of Washington Warren Nielson, PhD St. Joseph's Health Care, London, Ontario Bob Kerns, PhD, Yale University and VA Connecticut Healthcare System

2 Case studies, longitudinal designs, randomized controlled trials (RCTs) Psychosocial treatments for chronic pain are effective (ie, they work )

3 However, we do not know HOW psychosocial Tx s bring about favorable outcomes. The study of MECHANISMSlags far behind the study of efficacy.

4 Does it work? is not the same as How does it work?

5 Mechanisms fall into 2 broad categories Specific Theoretically-derived techniques and procedures unique to a Tx approach. Examples: CBT: change what people think about pain via restructuring MBSR: change how people think about pain via acceptance Nonspecific Aspects of therapy that are common features of most (if not all) Tx approaches sound therapeutic relationship pt expectations

6 Iceberg Berg Different Tx s (& putative specific mechanisms) Nonspecific Mechanisms Specific mechanisms may play roles Nonspecific factors may also be common foundation Pre-Tx Post-Tx

7 Cognitive-behavioral Tx s for chronic pain conditions have been widely studied Hypothesized specific mechanisms change appraisals, coping, and behavior via deliberate efforts to restructure pain-related cognition, amplify adaptive coping skills, increase activity these changes in turn are believed to lead to improved functioning and well-being

8 What evidence do we got? Mostly bupkis Showing that CBT works in typical RCT does NOT mean that it worked via hypothesized mechanisms Just because we did CR does not mean CR led to Tx gains RCTs for psychosocial pain Tx tend NOTto actually measure and analyze effects of alleged mechanisms Some evidence from longitudinal designs changes in cognition (pre-mid or pre-post) correlate with outcomes (midpost or pre-post) But NO definitive proof We simply do not know whether CBT for pain works via any mechanism rooted in CBT theory & practice

9 Tailored CBT vs Standard CBT for chronic pain patients 126 chronic pain patients randomly assigned to TCBT (MI + choice of Tx modules) or SCBT (no MI & pts yoked to pts in TCBT). VA Merit Review Award (PI -Kerns). 100 pts completed 12 wks of Tx Assessments at pre, 4 wk, 8 wk, post (n = 75) Allows examination of patterns of change during early and late Tx periods

10 Tailored CBT vs Standard CBT for chronic pain patients Because the Standard CBT was a very active control, Tx Groups were equivalent on all pre-post outcome changes and MI mechanism factors. Here, we collapsed across Tx condition and examined another feature of this study.

11 Tailored CBT & Standard CBT for chronic pain patients Pts completed 4 coping skills modules (out of 9 offered) in various orders during 12 wks. Discrete modules provided instruction and practice on copings skills (eg, increasing exercise, relaxation, positive coping self-statements, etc.) For their first module (wks 1-4), 59 pts received either Exercise, Relaxation, Cognitive Coping, Task Persistence/Pacing modules. Other 16 pts received 1 of other 5 modules Focus only on effects of 1 st module (wks 1-4) Effects not contaminated by effects of subsequent modules

12 Tailored CBT & Standard CBT for chronic pain patients Chronic Pain Coping Inventory (CPCI) subscales that tap particular coping skills addressed in the Exercise, Relaxation, Cognitive Coping, Task Persistence/Pacing modules State measure During the past week, how many days did you use each of the following at least once in the day to cope with your pain? Examples: Told myself things will get better; Meditated to relax Exercise, Relaxation, Coping self-statements, Task persistence subscales used as indexes

13 Tailored CBT & Standard CBT for chronic pain patients If coping skills improve because of the specific effects of the distinct coping skills training provided in a given module (ie specific mechanism), then a given module will produce large increases in the coping skill targeted by the module. a given module will produce small increases in other coping skills NOTtargeted by the module.

14 TCBT & SCBT: 1 st Modules x Relaxation CPCI subscale Relaxation Exercis e Task P/P Relaxation Coping SS Other 2 Pre 4-wk 8-wk Post Time Module x 4 Time Period F= 1.8; p <.05 Module x 2 Time Period F= 5.0; p <.01 All but Task P/P Signif Pre-4wk increase Pre- 4 wk: d =.47 Pre-12 wk: d =.77 Pre- 4 wk = 61% of total

15 TCBT & SCBT: 1 st Modules x Exercise CPCI subscale Exercise Exercis e Task P/P Relaxation Coping SS Other 2 Pre 4-wk 8-wk Post Time Module x 4 Time Period F= 1.4; p>.10 Module x 2 Time Period F= 1.3; p>.10 All except Task P/P Signif Pre-4 wk increase Pre 4 wk: d=.65 Pre 12 wk: d =.66 Pre- 4 wk = 99% of total

16 TCBT & SCBT: 1 st Modules x Coping SS CPCI subscale Coping Exercis e Task P/P Relaxation Coping SS Other 2 Pre 4-wk 8-wk Post Time Module x 4 Time Period F= 1.0 p >.10 Module x 2 Time Period F= 1.0 p >.10 All except Other Signif Pre-4wk increases Pre- 4 wk: d=.42 Pre- 12 wk: d=.44 Pre- 4 wk 95% of total

17 TCBT & SCBT: 1 st Modules x Task Persist CPCI subscale Task Persistence Exercis e Task P/P Relaxation Coping SS Other 2 Pre 4-wk 8-wk Post Time Module x 4 Time Period F < 1 Module x 2 Time Period F< 1 Task P/P & Other NonSignif Pre- 4 wk increase Pre- 4wk: d=.23 Pre- 12 wk: d=.39 Pre- 4 wk 60% of total

18 Specific and Nonspecific Mechanisms Despite different modules addressing distinct coping skills Only pts receiving the Relaxation module showed expected pattern of large relaxation skill increases These pts, however, also showed large increases on other coping skills (very responsive group) Most pts improved on most of the 4 coping skills regardless of which skill modules they received For all 4 coping subscales, most of the total pre to 12 wk changes occurred during pre to 4 wks. Does not support the notion that specific therapeutic operations were primarily responsible for specific changes

19 Relaxation Group ONLY on all CPCI subscales Subscale Values Relaxation Task P/P Exercis e Coping SS 2 Pre 4-wk 8-wk Post Time

20 Specific and Nonspecific Mechanisms Despite different modules addressing distinct coping skills Only pts receiving the Relaxation module showed expected pattern of large relaxation skill increases These pts, however, also showed large increases on other coping skills (very responsive group) Most pts improved on most of the 4 coping skills regardless of which skill modules they received For all 4 coping subscales, most of the total pre to 12 wk changes occurred during pre to 4 wks. Does not support the notion that specific therapeutic operations were primarily responsible for specific changes

21 Specific and Nonspecific Mechanisms So then, what explains the gains in coping skills if not the specific instruction given in distinct modules? A halo effect that lifts mood and results in improved self-report? Quality of the therapeutic relationship? Pt beliefs that Tx is credible and potentially helpful? Mood lift: BDI changes from pre to 4 wks Therapeutic relationship: Working Alliance Inventory (WAI) at wk 4 Pt beliefs: tx credibility ratings at wk 3.

22 Specific and Nonspecific Mechanisms BDI pre- to 4 wk changes Relaxation pre to 4 wk change Exercise pre to 4 wk change WAI at 4 wks Credibility rating at 3 wks Coping SS pre to 4 wk change Task Persistence pre to 4 wk change Significant r s >.22

23 Specific and Nonspecific Mechanisms Nonspecific Tx mechanisms related to early-tx coping skills acquisition and use. Quality of therapeutic relationship (ie, working alliance) between pt and therapist consistently related Suggests that factors other than specific training geared toward increasing adoption and practice of coping skills may have contributed to coping skills gains And did so irrespective of Tx module. But, no definitive proof of causation for coping training or nonspecific factors

24 Okay. Now what? We CANNOT hide from the fact that we really do not know HOW our psychosocial Tx s work. When Kazdin (2007) stated, whatever may be the basis of changes with Cognitive Therapy, it does not seem to be the cognitive changes originally proposed, he was NOT advocating denial or surrender. He was challenging us to do a better job of finding clues and uncovering mechanisms.

25 RCTs and mechanisms First, we have to accept the fact that knowing HOW it works is CRUCIAL. Examining effects of specific and nonspecific mechanisms in the context of RCTs is vital to evaluate true public health value of any psychosocial intervention for chronic pain. If exercise coping skills training works nearly as well as coping selfstatements training AND perhaps via the same specific and nonspecific mechanisms, then are both needed? are either needed? Second, we need to broaden the typical RCT s narrow focus on outcomes by borrowing methods from state-of-the-art psychotherapy research Examine course of mechanism and outcome change over course of Tx Examine cross-lagged associations between mechanism and outcome changes Examine relative impacts of specific and nonspecific factors Therapeutic relationship long studied elsewhere- virtually absent from study of behavioral medicine interventions

26 Support for the data reported here was provided by the Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Clinical Science Research and Development Service The views expressed in this presentation are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs