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Question In patients with subsyndromal depression, are cognitive behavioural therapy (CBT) and psychodynamic interpersonal therapy (PIT) effective when given using a 2 + 1 model (2 one hour sessions 1 week apart followed by a third 1 hour session 3 months later)?
Design
Randomised (stratified by severity of depression) controlled trial with follow up to 1 year. The study had a 2 × 2 × 3 factorial design (treatment type × delay × severity).
Setting
A psychotherapy clinic in the Medical Research Council Unit at the University of Sheffield, UK.
Patients
138 patients with subsyndromal depression were randomised. 116 completed the study (mean age 45 y, 58% men). Patients were stratified for severity on the Beck Depression Inventory (BDI) as stressed (n=29), subclinical (n=48), or low level clinically depressed (n=39). Exclusion criteria were >3 sessions of formal therapy in the previous 5 years, a substantive change in medication regimen within the previous 6 months, mania, or psychotic symptoms.
Intervention
Patients were assigned to CBT or PIT. Each treatment was given in 1 of 2 timeframes, immediately or after a 4 week delay (which acted initially as a control condition). Treatment was given using a 2 + 1 model. The PIT method was based on Hobson's (1985) Conversational Model. The CBT method was multimodal and more behavioural than Beck's cognitive therapy.
Main outcome measure
Change in score on the BDI.
Main results
Improvement rates at the end of treatment were 67% (stressed), 72% (subclinical), and 65% (low level clinically depressed). At the end of treatment the average patient was within 0.25 SDs of a non-distressed population as measured using the BDI. These gains were still evident 1 year later. A delay in treatment did not compromise the effectiveness. No differences existed between the CBT and PIT groups, with the exception at 1 year follow up when the BDI showed an advantage for CBT (effect size difference between CBT and PIT 0.57, p=0.015).
Conclusion
In patients with subsyndromal depression, a very brief 3 session intervention of cognitive behavioural therapy or psychodynamic interpersonal therapy was effective.
Commentary
Many studies have examined the efficacy of CBT for depression (for a recent meta-analysis see Gloaguen et al1). Barkham et al add to this existing knowledge. Their main contribution, however, lies in response to the current demands on the clinician to do what works and to do it faster.
Evidence, from a formal trial, that brief interventions—cognitive behavioural and psychodynamic—are effective for mild depression is welcomed by the clinician. As the authors point out, the allocation of scarce resources has led to situations where clinicians do not usually treat patients at this level of distress. When it is possible, however, such as in primary care, the clinician has the opportunity to put into practice the approach of a “stitch in time.” This trial has attempted to define and test treatment methods that would be economic, feasible, and effective in the treatment of depression.
Over 20 years ago, Rush et al noted that much of the therapeutic change in CBT occurs within the first few weeks of treatment.2 Recently, the benefit of brief psychodynamic interpersonal therapy has also been shown.3 This study by Barkham et al supports these observations. The limitations of this study are succinctly discussed by the authors. It is clear that research findings that can be generalised to clinical practice are needed.4 The “dose effect design” provides data about the “average” subject. Clinicians are sensitive to the high variability of improvement across patients.
Footnotes
Source of funding: not stated.
For correspondence: Dr M Barkham, Psychological Therapies Research Centre, University of Leeds, 17 Blenheim Terrace, Leeds LS2 9JT, UK. Fax +44 (0)113 233 1956.