I recently looked again at Professor Michel Dugas's interesting work on Generalized Anxiety Disorder (GAD) at Concordia University, Montreal.  On his Anxiety Disorders Lab website he writes: "Over the past 17 years, I have conducted clinical research on the psychological processes involved in the etiology of generalized anxiety disorder (GAD). This line of research has led to the development of a cognitive-behavioural treatment for GAD ... which targets the four model components (intolerance of uncertainty, positive beliefs about worry, negative problem orientation, and cognitive avoidance), has now been validated in four randomized controlled trials ... Overall, the results from these studies show that the treatment is efficacious for the majority of individuals with GAD, and that gains are maintained and even augmented over periods of at least two years following treatment. Although these findings are encouraging, our research group is currently investigating ways of improving treatment efficacy by refining our understanding of the mechanisms involved in the development, maintenance, and treatment of excessive worry and GAD."  

The site gives details of his many research studies on GAD (sadly without providing abstracts or PDF's).  Interestingly most of the early studies have Mark Freeston as one of his co-authors.  Kevin Meares and Mark Freeston have written a fine self-help book for GAD sufferers called "Overcoming worry" which is based on the Dugas model.  Michel Dugas and co-author Melisa Robichaud have also written a helpful text "Cognitive-behavioral treatment for generalized anxiety disorder: from science to practice" which is aimed more at health professionals wanting to learn this particular CBT approach for GAD.  The Concordia website also gives a good description of GAD and freely downloadable PDF's of five useful questionnaires - Worry & Anxiety, Intolerance of Uncertainty, Why Worry-II, Negative Problem Orientation, and Cognitive Avoidance.  All in all, this is a helpful website for introducing this interesting CBT approach for worry and GAD.  It would be a lot better still if it included downloadable PDF's of his research papers!

Despite my enthusiasm for Dugas's work, it is worth repeating his line "Although these findings are encouraging, our research group is currently investigating ways of improving treatment efficacy by refining our understanding of the mechanisms involved in the development, maintenance, and treatment of excessive worry and GAD."  Fairly complex, painstakingly developed CBT treatment packages for GAD are still not much better than well taught Applied Relaxation.  Further down this page I list the abstracts of three research papers from the last decade (Ost and Breitholtz 2000; Siev and Chambless 2007; Dugas, Brillon et al. 2010) that illustrate this lack of progress including a recent one from Dugas's own research team.  Possibly counter-intuitively, applied relaxation is effective for worry, just as more complex CBT is effective for physical anxiety symptoms - treatment effects are "bidirectional" (Dugas, Francis et al. 2009).  The situation parallels the way relatively simple Behavioural Activation approaches are as effective as more complex CBT treatment packages for depression (Ekers, Richards et al. 2008; Trevor, Robert et al. 2009).  In both cases there is a strong argument for training therapists to skilfully apply the simpler approaches of Applied Relaxation and Behavioural Activation - possibly in group formats - and then researching whether adding more complex CBT interventions increase success rates for anyone who doesn't respond fully enough to the initial more straightforward therapies.

(Note: Fascinatingly some months later NICE came to a somewhat similar conclusion (easy to forget with our current focus on mindfulness). See "New NICE guidance on the treatment of generalised anxiety disorder (GAD) and panic disorder (with or without agoraphobia)".) 

Dugas, M. J., P. Brillon, et al. (2010). "A randomized clinical trial of cognitive-behavioral therapy and applied relaxation for adults with generalized anxiety disorder." Behav Ther 41(1): 46-58.  [PubMed] 
This randomized clinical trial compared cognitive-behavioral therapy (CBT), applied relaxation (AR), and wait-list control (WL) in a sample of 65 adults with a primary diagnosis of generalized anxiety disorder (GAD). The CBT condition was based on the intolerance of uncertainty model of GAD, whereas the AR condition was based on general theories of anxiety. Both manualized treatments were administered over 12 weekly 1-hour sessions. Standardized clinician ratings and self-report questionnaires were used to assess GAD and related symptoms at pretest, posttest, and at 6-, 12-, and 24-month follow-ups. At posttest, CBT was clearly superior to WL, AR was marginally superior to WL, and CBT was marginally superior to AR. Over follow-up, CBT and AR were equivalent, but only CBT led to continued improvement. Thus, direct comparisons of CBT and AR indicated that the treatments were comparable; however, comparisons of each treatment with another point of reference (either waiting list or no change over follow-up) provided greater support for the efficacy of CBT than AR.

Dugas, M. J., K. Francis, et al. (2009). "Cognitive behavioural therapy and applied relaxation for generalized anxiety disorder: a time series analysis of change in worry and somatic anxiety." Cogn Behav Ther 38(1): 29-41.  [PubMed]
The present study examined symptom change profiles in patients with generalized anxiety disorder (GAD) receiving either cognitive behavioural therapy (CBT) or applied relaxation (AR). It was hypothesized that (a) changes in worry would uniquely predict changes in somatic anxiety for most participants receiving CBT and (b) changes in somatic anxiety would uniquely predict changes in worry for most participants in the AR condition. Twenty participants (CBT n = 10; AR n = 10) completed daily ratings of worry and somatic anxiety during therapy, and multivariate time series analysis was used to assess the causal impact of each variable on the other. The hypotheses were not supported because we found no evidence of a match between individual symptom change profiles and treatment condition. Rather, a bidirectional relationship between worry and somatic anxiety was observed in 80% of participants receiving CBT and 70% of participants receiving AR. When only treatment responders were considered, 83% of participants receiving CBT and 86% of those receiving AR had such a bidirectional effect. The findings are discussed in terms of models of psychopathology that posit dynamic interactions between symptom clusters and in terms of the value of examining treatment mechanisms at the individual level.

Ekers, D., D. Richards, et al. (2008). "A meta-analysis of randomized trials of behavioural treatment of depression." Psychol Med 38(5): 611-23.  [PubMed]
BACKGROUND: Depression is a common, disabling condition for which psychological treatments, in particular cognitive behavioural therapies are recommended. Promising results in recent randomized trials have renewed interest in behavioural therapy. This systematic review sought to identify all randomized trials of behavioural therapy for depression, determine the effect of such interventions and examine any moderators of such effect. METHOD: Randomized trials of behavioural treatments of depression versus controls or other psychotherapies were identified using electronic database searches, previous reviews and reference lists. Data on symptom-level, recovery/dropout rate and study-level moderators (study quality, number of sessions, severity and level of training) were extracted and analysed using meta-analysis and meta-regression respectively. RESULTS: Seventeen randomized controlled trials including 1109 subjects were included in this meta-analysis. A random-effects meta-analysis of symptom-level post-treatment showed behavioural therapies were superior to controls [standardized mean difference (SMD) -0.70, 95% CI -1.00 to -0.39, k=12, n=459], brief psychotherapy (SMD -0.56, 95% CI -1.0 to -0.12, k=3, n=166), supportive therapy (SMD -0.75, 95% CI -1.37 to -0.14, k=2, n=45) and equal to cognitive behavioural therapy (SMD 0.08, 95% CI -0.14 to 0.30, k=12, n=476). CONCLUSIONS: The results in this study indicate behavioural therapy is an effective treatment for depression with outcomes equal to that of the current recommended psychological intervention. Future research needs to address issues of parsimony of such interventions.

Ost, L. G. and E. Breitholtz (2000). "Applied relaxation vs. cognitive therapy in the treatment of generalized anxiety disorder." Behav Res Ther 38(8): 777-90.  [PubMed]
The present study investigated the efficacy of a coping-technique, applied relaxation (AR) and cognitive therapy (CT), in the treatment of generalized anxiety disorder. Thirty-six outpatients fulfilling the DSM-III-R criteria for generalized anxiety were assessed with independent assessor ratings and self-report scales before and after treatment and at a 1 yr follow-up. The patients were randomized and treated individually for 12 weekly sessions. The results showed that both treatments yielded large improvements, which were maintained, or furthered at follow-up. There was no difference between AR and CT on any measure. The drop-out rate was 12% for AR and 5% for CT. The proportions of clinically significantly improved patients were 53 and 62% at post-treatment and 67 and 56% at follow-up for AR and CT, respectively. Besides affecting generalized anxiety the treatments also yielded marked and lasting changes on ratings of worry, cognitive and somatic anxiety and depression. The conclusion that can be drawn is that both AR and CT have potential as treatments for generalized anxiety disorder but they have to be developed further in order to increase the efficacy to the level usually seen in panic disorder, 80-85% clinically improved.

Siev, J. and D. L. Chambless (2007). "Specificity of treatment effects: cognitive therapy and relaxation for generalized anxiety and panic disorders." J Consult Clin Psychol 75(4): 513-22.  [PubMed]
The aim of this study was to address claims that among bona fide treatments no one is more efficacious than another by comparing the relative efficacy of cognitive therapy (CT) and relaxation therapy (RT) in the treatment of generalized anxiety disorder (GAD) and panic disorder without agoraphobia (PD). Two fixed-effects meta-analyses were conducted, for GAD and PD separately, to review the treatment outcome literature directly comparing CT with RT in the treatment of those disorders. For GAD, CT and RT were equivalent. For PD, CT, which included interoceptive exposure, outperformed RT on all panic-related measures, as well as on indices of clinically significant change. There is ample evidence that both CT and RT qualify as bona fide treatments for GAD and PD, for which they are efficacious and intended to be so. Therefore, the finding that CT and RT do not differ in the treatment of GAD, but do for PD, is evidence for the specificity of treatment to disorder, even for 2 treatments within a CBT class, and 2 disorders within an anxiety class.

Trevor, M., K. Robert, et al. (2009). "Behavioral Activation Treatments for Depression in Adults: A Meta-analysis and Review." Clinical Psychology: Science and Practice 16(4): 383-411.  [Abstract/Full Text]
Behavioral activation (BA) treatments for depression require patients to increase overt behavior to bring them in contact with reinforcing environmental contingencies. This meta-analysis sought to identify all randomized controlled studies of BA, determine the effect of this approach, and examine the differential effectiveness of variants. Thirty-four studies with 2,055 participants reporting symptoms of depression were included. The pooled effect size indicating the difference between BA and control conditions at posttest was 0.78. For participants who satisfied the criteria for major depressive disorder, the overall effect size of 0.74 remained large and significant. No differences in effectiveness between BA and cognitive therapy were found. BA may be considered a well-established and advantageous alternative to other treatments of depression.