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Unread April 16th, 2006, 09:27 PM
James Pretzer James Pretzer is offline
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Join Date: Jun 2004
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Default Biological predictors of response to treatment

A very interesting study was able to predict which depressed patients would be successfully treated by 16 sessions of CBT using a pre-treatment fMRI measure. (Siegle GJ. Treatment was effective for 78% of individuals with depression who had low sustained reactivity in the subgenual cingulate cortex (Brodmann's area 25) after they read and rated negative words. However, only 20% of participants who had no fMRI evidence of decreased activity in the same region on the negative-word rating task, had remission of depressive symptoms after completing CBT. See: "Use of fMRI to Predict Recovery From Unipolar Depression With Cognitive Behavior Therapy" Am J Psychiatry 2006; 163:735-738. (A summary can be found at

The study used a very small sample (16 Ss in all) and definitely needs replication and further analysis. However, it could be a major advance in figuring out which individuals are good candidates for CBT and in figuring out why not everyone responds to CBT. It would be great if we had some way to tell who is a good candidate for CBT.

However, don't get carried away with this finding. From the summary, it sounds as though the authors are concluding that CBT will be ineffective for the group that does not show evidence of decreased activity in Area 25. However, the evidence does not show that this is the case, it simply shows a difference in response to the particular CBT protocol used in this study. It is possible that this group of individuals needs more than 16 weeks of treatment or needs a somewhat different CBT protocol. Also, how much does fNMR cost? I bet it's cheaper to try CBT and see if it works than to pay for fNMR in order to predict if CBT will work.

In discussing this finding, Brad Alford pointed out a brief summary in the March 31 2006 Science (p. 1843) of an article to appear in the May issue of the American Journal of Human Genetics. DNA samples from 1,953 patients with MDD were analyzed and those with a gene coding for the 2A serotonin receptor had an 80% response rate to SSRIs while only 62% of those with 2Gs responded to SSRIs. This study didn't examine response to CBT so we don't know if the group who were less likely to respond to SSRIs would respond well to CBT or not. Stay tuned for future developments.
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