There was some discussion at the SIGN "Non-pharmacological management of depression" seminar about the possible importance of the therapeutic alliance in depression treatment.  Professor Kevin Power said that SIGN had not found any good research that threw light on this issue.  This is somewhat surprising because there is a fair amount of published research that does address this point.  It is however a bit harder to scan the literature for - Medline, for example, has no searchable keyword phrase like "therapeutic alliance".

I already mentioned the CBASP study, in my 5^th blog posting on the SIGN guideline, that reported early therapeutic alliance significantly predicted subsequent improvement in depressive symptoms after controlling for prior improvement and 8 prognostically relevant patient characteristics. Patients receiving combination treatment reported stronger alliances with their psychotherapists than patients receiving CBASP alone (Klein, Schwartz et al. 2003).  As far as I'm aware, the most relevant sequence of studies on the importance of alliance in depression treatment are those on the classic NIMH Treatment of Depression Collaborative Research Program (Elkin, Shea et al. 1989).  They're still mining the data from this very important research study, and several of the papers that have emerged have focussed on the alliance.  Krupnick and colleagues (Krupnick, Sotsky et al. 1996) scored videotapes of 619 treatment sessions for alliance quality.  They concluded "Therapeutic alliance was found to have a significant effect on clinical outcome for both psychotherapies and for active and placebo pharmacotherapy."  I have a further seven papers also addressing alliance factors in the NIMH study in my own database (Blatt, Quinlan et al. 1996; Zuroff, Blatt et al. 2000; Meyer, Pilkonis et al. 2002; Hawley, Ho et al. 2006; Kim, Wampold et al. 2006; McKay, Imel et al. 2006; Zuroff and Blatt 2006).  There is a special section in a 2006 issue of the journal of Psychotherapy Research where the Kim et al study is joined by another six papers discussing therapeutic factors in the NIMH study.  Various authors are making major evidence-based claims that the therapeutic alliance is more important than the specific form of therapy when treating depression.  So McKay et al analysed the NIMH data and concluded "The proportion of variance in the BDI scores due to medication was 3.4% (p < .05), while the proportion of variance in BDI scores due to psychiatrists was 9.1% (p < .05). The proportion of variance in the HAM-D scores due to medication was 5.9% (p < .05), while the proportion of variance in HAM-D scores due to psychiatrist was 6.7% (p = .053). Therefore, the psychiatrist effects were greater than the treatment effects" (McKay, Imel et al. 2006).  While Kim et al argued for the priority of therapist effects in the NIMH interpersonal and CBT psychotherapy treatments, concluding "These analyses, which modeled therapist variability in several different ways, indicated that about 8% of the variance in outcomes was attributable to therapists, whereas 0% was due to the particular treatment delivered" (Kim, Wampold et al. 2006).

These are major claims that I think SIGN should look at very carefully.  The findings are certainly not just limited to the classic NIMH study.  Burns et al in 1992 looked at the importance of therapeutic empathy in quite a large series of patients and concluded "This study demonstrated that therapeutic empathy has a moderate-to-large causal effect on recovery from depression in a group of 185 patients treated with cognitive-behavioral therapy (CBT)" (Burns and Nolen-Hoeksema 1992).  Castonguay et al - again in a non-NIMH sample - made the even more challenging claim that not only is alliance a significant factor in determining outcome in CBT treatment for depression, but actually adherence to certain technical aspects of the therapy (possibly to the detriment of the alliance) seems to reduce therapeutic benefits (Castonguay, Goldfried et al. 1996).  While Trepka et al analysing a further series of CBT treatments for depression concluded "Both therapeutic alliance and therapist competence were related to outcome. In regression analyses, the alliance remained significantly related to outcome when controlling for competence, but not vice versa" (Trepka, Rees et al. 2004).  I have discussed these issues - including their relevance to therapist training - in a talk entitled "The alliance is crucial.  What are the implications?" that I gave at this year's British Association for Behavioural and Cognitive Psychotherapies (BABCP) annual conference (Hawkins 2008).  It is important SIGN appreciate and note the importance of this area in their overview of "Non-pharmacological management of depression".

Blatt, S. J., D. M. Quinlan, et al. (1996). "Interpersonal factors in brief treatment of depression: further analyses of the National Institute of Mental Health Treatment of Depression Collaborative Research Program." J Consult Clin Psychol 64(1): 162-71.  [PubMed] 
Burns, D. D. and S. Nolen-Hoeksema (1992). "Therapeutic empathy and recovery from depression in cognitive-behavioral therapy: a structural equation model." J Consult Clin Psychol 60(3): 441-9.  [PubMed]  
Castonguay, L. G., M. R. Goldfried, et al. (1996). "Predicting the effect of cognitive therapy for depression: a study of unique and common factors." J Consult Clin Psychol 64(3): 497-504.  [PubMed] 
Elkin, I., M. T. Shea, et al. (1989). "National Institute of Mental Health Treatment of Depression Collaborative Research Program. General effectiveness of treatments." Arch Gen Psychiatry 46(11): 971-82; discussion 983.  [PubMed] 
Hawkins, J. (2008). The alliance is crucial.  What are the implications? BABCP 36th Annual Conference. Edinburgh, 17-19 July.  [Free Full Presentation]
Hawley, L. L., M.-H. R. Ho, et al. (2006). "The Relationship of Perfectionism, Depression, and Therapeutic Alliance During Treatment for Depression: Latent Difference Score Analysis  " Journal of Consulting and Clinical Psychology 74(5): 930-942.  [PubMed]
Kim, D.-M., B. E. Wampold, et al. (2006). "Therapist effects in psychotherapy: A random-effects modeling of the National Institute of Mental Health Treatment of Depression Collaborative Research Program data. ." Psychotherapy Research 16(2): 161-172.  [Abstract/Full Text]
Klein, D. N., J. E. Schwartz, et al. (2003). "Therapeutic alliance in depression treatment: controlling for prior change and patient characteristics." J Consult Clin Psychol 71(6): 997-1006.  [PubMed] 
Krupnick, J. L., S. M. Sotsky, et al. (1996). "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." J Consult Clin Psychol 64(3): 532-9.  [PubMed] 
McKay, K. M., Z. E. Imel, et al. (2006). "Psychiatrist effects in the psychopharmacological treatment of depression." J Affect Disord 92(2-3): 287-90.  [PubMed]
Meyer, B., P. A. Pilkonis, et al. (2002). "Treatment expectancies, patient alliance, and outcome: further analyses from the National Institute of Mental Health Treatment of Depression Collaborative Research Program." J Consult Clin Psychol 70(4): 1051-5.  [PubMed]
Trepka, C., A. Rees, et al. (2004). "Therapist Competence and Outcome of Cognitive Therapy for Depression." Cognitive Therapy and Research 28(2): 143-157.  [Abstract/Full Text] 
Zuroff, D. C. and S. J. Blatt (2006). "The therapeutic relationship in the brief treatment of depression: contributions to clinical improvement and enhanced adaptive capacities." J Consult Clin Psychol 74(1): 130-40.  [PubMed]