Saturday, April 20, 2019

Comments by The-Mental-Elf

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  • The Johnsen and Friborg meta-analysis is deeply flawed:

    1. The most important limitation is the combination of uncontrolled and controlled trials, or rather of non-randomised and randomised studies in the meta-analysis.

    2. They only included 15 RCTs in their study, but there are many more published trials in this field. Why were the others excluded?

    3. It’s well documented that the quality of trials has improved over time. It is therefore plausible that the apparent decrease in the efficiency of CBT for depression over time might simply be a by-product of increasing quality of trials. Johnsen and Friborg did look at study quality and found no moderating effect. But given their hotchpotch of uncontrolled and controlled trials and their limited sample of CBT studies, this analysis is not very informative.

    4. There is no analysis of heterogeneity in the study. The authors say they did this, but it’s not present in the published paper. Given their combination of studies, heterogeneity was probably very high. So high, in fact, as to indicate there is not much point in combining these studies at all.

    We have blogged about this meta-analysis today on the Mental Elf. You can read more here: http://www.nationalelfservice.net/treatment/cbt/crisis-of-faith-instead-of-cbt-we-should-be-worrying-about-meta-analyses/

    Cheers,
    André Tomlin
    The Mental Elf