© 2001 The Royal College of Psychiatrists
Correspondence |
Cognitive therapy and social functioning in chronic depression
Department of Psychiatry, Nagoya City University Medical School, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
We clinicians constantly encounter patients with major depression in partial remission. They are no longer acutely depressed but continue to present with substantial functional impairment (Paykel et al, 1995). For treatment-resistant depression, only one pharmacological intervention can be recommended today with reasonable evidence, namely lithium augmentation (Austin et al, 1991; Aronson et al, 1996), but this may not be the answer for those with low-grade residual depression.
Scott et al (2000) demonstrated that cognitive therapy can help these people. Critically appraising their article in our evidence-based psychiatry case conference, however, it was very difficult for us to appreciate the substantive significance of this improvement, because only means and standard deviations of scores on the Social Adjustment Scale were reported. Analyses based on these data can show whether or not the treatment is better than the control condition, but cannot show how much better it is - a crucial piece of information for both patients and clinicians. We therefore resorted to the normative data for this scale (Bothwell & Weissman, 1977). Calculation based on the means and standard deviations under the assumption of a normal distribution showed that, at week 20, 68% of patients with residual depression reached the 95% range of the control subjects when treated with clinical management plus cognitive therapy, whereas only 45% did so when treated with clinical management only. This translates into a ‘number needed to treat’ of 4.4 (95% CI 2.6-12.6).
This is an impressive figure. By adding 16 sessions of cognitive therapy to usual care, we can achieve social remission in one additional patient out of four, compared with continued standard care only. The original authors had concluded, "In patients showing only partial response to antidepressants, the addition of CT produced modest improvement in social and psychological functioning". We find that the improvement was more than modest and would be clinically meaningful.
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[Abstract/Free Full Text] - Bothwell, S. & Weissman, M. M. (1977) Social impairments four years after an acute depressive episode. American Journal of Orthopsychiatry, 47, 231-237.[Medline]
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[Abstract/Free Full Text]
Author's reply
Department of Psychological Medicine, Academic Centre, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH
I am a strong advocate of the use of cognitive therapy in chronic and residual depressive disorders. I am therefore the last to disagree with the comments of Ito and colleagues that there is real benefit in providing psychosocial treatments to individuals with residual depressive symptoms. My comment on social functioning was not meant to under-estimate the benefits, but paid heed to two factors. First, although individuals who received cognitive therapy undoubtedly showed significant improvements in social functioning, there were still obvious impairments within this population. Second, and very importantly, the differences between the cognitive therapy group and the control group were only apparent during the active phase of treatment — the control group continued to make modest gains during the follow-up period so that at 1 year after cognitive therapy there was no difference in social functioning between the two groups. One conclusion from this result is that individuals who receive 16 sessions of cognitive therapy for chronic or residual depressive symptoms may benefit from additional but less-frequent maintenance cognitive therapy sessions.
Lastly, Ito et al are right to point out that calculations of numbers needed to treat from this study are indeed indicative of substantial benefits from using cognitive therapy. For the record, using data from our study and other recent studies, only four to six additional patients need be treated with cognitive therapy to prevent one relapse.
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