Tuesday, 11 March 2008


As I mentioned below, I'm amused that the apparent limitations of anti-depressants have lead to an enthusiastic embracing of cognitive behavioural therapy.

I thought I'd share NICE's view of the evidence for CBT:

"In the only comparison available from a single trial there was insufficient evidence to determine the efficacy of individual CBT for depression compared with either pill placebo (plus clinical management) or other psychotherapies. However, stronger data do exist when CBT is compared with antidepressants (a number of which include clinical management); here individual CBT is as effective as antidepressants in reducing depression symptoms by the end of treatment. These effects are maintained a year after treatment in those treated with CBT whereas this may not be the case in those treated with antidepressants. CBT appears to be better tolerated than antidepressants, particularly in patients with severe to very severe depression. There is a trend suggesting that CBT is more effective than antidepressants on achieving remission in moderate depression, but not for severe depression. There was also evidence of greater maintenance of a benefit of treatment for CBT compared with antidepressants.
We recognise that this is a different finding to that of Elkin et al. (1989).
Adding CBT to antidepressants is more effective than treatment with antidepressants alone, particularly in those with severe symptoms. (This is the subject of a costeffectiveness analysis in Chapter 9.) There is no evidence that adding an antidepressant to CBT is generally helpful, although we have not explored effects on specific symptoms (e.g. sleep). There is insufficient evidence to assess the effect of CBT plus antidepressants on relapse rates.
There is evidence from one large trial (Keller et al., 2000) for chronic depression that a combination of CBT and antidepressants is more beneficial in terms of remission than either CBT or antidepressants alone. In residual depression the addition of CBT may also improve outcomes.
It appears to be worthwhile adding CBT to antidepressants compared with antidepressants alone for patients with residual depression as this reduces relapse rates at follow-up, although the advantage is not apparent post-treatment.
In regard to modes of delivery there is evidence that group CBT is more effective than other group therapies, but little data on how group CBT fares in comparison with individual CBT. Much may depend on patient preferences for different modes of therapy.
However, group mindfulness-based CBT appears to be effective in maintaining response in people who have recovered from depression, particularly in those who have had more than two previous episodes."

What is worth noticing here is that CBT advocates ought to be a little careful in crowing about the alleged failings of anti-depressants with respect to their effect being not big enough compared to placebos to be 'clinically significant' since CBT has not been shown to be better than pill placebo at all, and their effect size is comparable to anti-depressants:

"There is evidence suggesting that there is no clinically significant difference
between CBT and antidepressants on:
● reducing depression symptoms by the end of treatment as measured by the BDI (N = 86; n = 480; SMD = –0.06; 95% CI, –0.24 to 1.12) or HRSD (N = 107; n = 1096; SMD = 0.01; 95% CI, –0.11 to 0.13)
● increasing the likelihood of achieving remission as measured by the HRSD (N = 5; n = 839; RR = 1; 95% CI, 0.91 to 1.10).

A sub-analysis by severity did not indicate any particular advantage for antidepressants over CBT based on severity of depression at baseline.

When analysed by severity, there is evidence suggesting that there is no clinically significant difference between CBT and antidepressants on reducing depression symptoms by the end of treatment"

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