Systematic review
Effects of psychotherapy for adults with depression
Systematic review
|Updated
What are the effects of psychotherapy on depression symptomatology and quality of life indicators for adults with depression?
Key message
In October 2008, the Norwegian Directorate of Health commissioned the Norwegian Knowledge Centre for the Health Services (NOKC) to complete a review about the effects of psychotherapy for adults with depression. The review would help answer the question of how adults with depression should be best managed. We addressed one main question: What are the effects of psychotherapy on depression symptomatology and quality of life indicators for adults with depression?
We searched systematically for relevant literature in international scientific databases. We evaluated newly published systematic reviews and randomized controlled trials (RCTs) for inclusion using a pre-designed inclusion form. We then appraised the methodological quality of the included studies with appropriate check lists, and summarised the results in tables and text. In accordance with the commissioner's requests, we gave emphasis to findings from the systematic reviews and results related to psychodynamic psychotherapy.
We included and summarised results from a total of nine studies; six systematic reviews and three RCTs. The great majority of the studies were of high methodological quality. Study results show that patients significantly improved post-treatment. Findings suggest that psychotherapy is effective in reducing patients' depression symptomatology compared to treatment as usual. Improvements in depression symptomatology and social functioning appear to be modest, improvements are similar to those observed for psychopharmacological treatments, and no psychotherapy technique appears to be superior. Psychodynamic psychotherapy does not seem to cause greater improvements in depression symptomatology compared to other types of psychotherapy.
Based on the best available evidence, it appears that psychotherapy improves depression symptomatology in adults with depressive illnesses. However, the literature search was restricted and the evidence base for the current review was heterogeneous, thus the results must be viewed as tentative.
Summary
Background
High prevalence of psychiatric morbidity has been reported both internationally and nationally. Estimates indicate that 20-30 percent of the general public receive a psychiatric diagnosis every year. Depression is the most common diagnosis, suffered by approximately ten percent of the population at any time. Generally, treatment for depression involves antidepressant medications and various forms of talk-therapy. Their effects, however, are debated.
In October 2008, the Norwegian Directorate of Health commissioned the Norwegian Knowledge Centre for the Health Services (NOKC) to complete a review about the effects of psychotherapy for adults with depression. The review would help answer the question of how adults with depression should be best managed.
We addressed one main question: What are the effects of psychotherapy on depression symptomatology and quality of life indicators for adults with depression?
Methods
We searched systematically for relevant literature in international scientific databases. The search was restricted to adults with depression; forms of psychotherapy; comparisons defined as treatment as usual (TAU); and outcomes related to reduction in depressive symptomatology. We searched for recent publications (2000-2008) in English and Scandinavian languages.
Two reviewers independently evaluated systematic reviews and randomized controlled trials (RCTs) for inclusion using a pre-designed inclusion form. We then appraised the methodological quality of the included studies with appropriate check lists, and summarised the results in tables and text.
In accordance with the commissioner's requests, we gave emphasis to findings from the systematic reviews and results related to psychodynamic psychotherapy (PDT).
Results
We included and summarised results from a total of nine studies; six systematic reviews and three RCTs. The great majority of the studies were of high methodological quality, but collectively heterogeneous. On average, the systematic reviews included 28 studies with about 1900 participants, who all were adults suffering from depression. A range of psychotherapies were represented, but psychodynamic psychotherapy was most commonly studied. Typically, one variant of psychotherapy was compared to another, although some studies contrasted psychotherapy with treatments collectively referred to as "treatment as usual" (TAU).
Given the high degree of heterogeneity across studies, we were only able to conduct semi-quantitative analyses. Nevertheless, six findings are noteworthy:
(1) Results from both the systematic reviews and the RCTs show that patients receiving any variant of treatment significantly improved to a degree where they were no longer considered clinically depressed or they experienced significantly fewer symptoms post-treatment compared to baseline.
(2) None of the studies directly compared short term and long term effects of psychotherapy. However, results from a meta-regression with time as moderator show that improvements are unrelated to the timing of the follow-up. Additional studies showing that the improvements persist, support the conclusion that the effects are sustained over several months.
(3) Measures of depression showed moderately greater treatment effects relative to usual general practitioner (GP) care. According to several analyses, patients receiving psychotherapy were three times more likely to experience fewer symptoms of depression up to nine months post-treatment compared to those receiving GP care or other treatment as usual.
(4) Robust results from two studies suggest there are no significant differences in depression symptomatology or social functioning between psychotherapy and antidepressant medication.
(5) There are few indications that one of the variants of psychotherapy is more or less efficacious than the other treatments. Most patients will likely improve from psychotherapy treatment, irrespective of technique provided. However, whether or not the treatment is intended to be therapeutic ("bona fide") is likely a determining factor.
(6) The evidence comparing PDT with other variants of psychotherapy does not suggest there are any differences in post-treatment recovery. No significant differences were demonstrated between PDT and cognitive behavioural therapy, behavioural therapy, support therapy, or other variants of psychotherapy.
Conclusion
Based on the best available evidence, it would appear that various forms of treatments – psychotherapy, antidepressant medications, and GP care – are beneficial in the treatment of people with depression. Improvements in depression symptomatology and social functioning appear to be modest and no variant of psychological treatment appears to be superior. However, the current systematic review was brief and the evidence base heterogeneous, thus the results must be viewed as tentative.
Depression severity, degree of therapeutic intention, and possibly the number of sessions offered are factors likely to affect outcome. Little can be said about the effects of short term and long term treatments attached to the provision of psychological treatment. Further trials of all types of psychological treatments involving appropriately recruited representative patient samples, who meet the diagnostic criteria for depressive disorder, are required.