CBT luminaries are spinning the plates furiously this conference season, a paper in next months Behavior Therapy, 50 (2019) 864–885 by clinicians from the University of Sheffield, has an abstract that advocates Group Behavioral Activation for depression as a front line treatment. The abstract also claims a moderate to large effect on depressive symptoms. Most people are unlikely to read further than the abstract, but closer inspection reveals the conclusions are deeply flawed.
In passing the abstract mentions that the standardized mean difference (SMD) between group BA and waiting list was 0.72. This would cause few people to question the findings, but actually it means the results are of doubtful clinical relevance, as it actually means there is less than one standard deviation in outcome between the treated group and the waiting list. Your eyes may already be glazing over at the thought that some stats are on the way, but bear with me. If a group of depressed patients had a mean Beck Depression Inventory Score of 28 at the start of treatment, [assuming that the spread of the results was 7, the standard deviation – taken from the Scott and Stradling (1990) study Behavioural Psychotherapy, 18, 1-19 ] a mean score of 23 at the end of treatment would produce an SMD of 0.71, i.e about the same as in the University of Sheffield analysis. Thus the average person experiencing this change of score is unlikely to feel that they are back to their normal selves, and are likely to view it as part of the normal cycling of mood, influenced by positive events e.g the company/support of fellow sufferers for a time in a group. In none of the Group BA studies was there an independent assessor determining whether clients were still depressed or the permanence of any change. Unsurprisingly the authors found that the Group BA was no better than any other active treatment (i.e controlling for attention and expectation), and make an implicit plea for the Dodo verdict ‘ all therapies are equal and must have prizes’.
In the body of the paper the authors acknowledge that the Group BA studies are of low quality, save one and that analyses were on treatment completers as opposed to the more rigorous intention to treat. But there is no indication anywhere as to what proportion of people recover from depression with any permanence. Yet this did not stop the spin in the abstract! Unfortunately it will likely be music to the ears of IAPT and one can expect Group BA to be soon advocated, particularly as it is contended that BA is easier for therapists to learn than CBT.
In 1990 Steve Stradling and I had published [Behavioural Psychotherapy, 18, 1-19] a study of depressed clients comparing, group CBT, individual CBT and a waiting list condition. For Group CBT the initial mean BDI was 29.0 and end of treatment score was 6.2 whilst for individual treatment the comparable scores were 28.21 and 11.53. However those on the waiting list also improved from 25.89 initially to 20.26 at the end of waiting list. Thus, it is far from clear that the results from the University of Sheffield analysis on Group BA are actually better than those of putting people on a waiting list.
In the August 2015 issue of the Psychologist I wrote:
“In the July issue of the Psychologist you referred to a meta-analysis of 70 CBT studies for depression conducted by Johnsen and Friborg (2015) and opined ‘CBT doesn’t seem to be helping reduce depression symptoms as much today as it used to when it was first developed in the 1970s’. But this conclusion may be premature, inspection of Table One of Johnsen and Friborg’s study shows that from 1977 up to and including the millennium 85% of studies were randomised controlled trials (RCT’s) but from 2001-2014 the comparable figure was 65%. One of the hallmarks of an RCT is blind assessment, using a standardised diagnostic interview. Thus there can be no certainty that populations treated post the millennium are comparable to those before. Johnsen, T. J., & Friborg, O. (2015, May 11). The Effects of Cognitive Behavioral Therapy as an Anti-Depressive Treatment is Falling: A Meta-Analysis. Psychological Bulletin. Advance online publication. http://dx.doi.org/10.1037/bul0000015″ Reliance on weak evidence has become a post-millenium phenomenon.
But spin is not confined to recent CBT studies, Jellison et al (2019) have examined spin in leading journals of psychiatry and in the journal Psychological Medicine, of 116 randomised controlled trials spin was identified in 56% of them, with 21% in the abstract results section and 49.1% in the abstract conclusions section. See link below:
Please let me know what work should be given a spin award this conference season.
Dr Mike Scott