Differences in brain glucose metabolism between responders to CBT and venlafaxine in a 16-week randomized controlled trial.

OBJECTIVE

Neuroimaging investigations reveal changes in glucose metabolism (fluorine-18-fluorodeoxyglucose positron emission tomography [PET]) associated with response to disparate antidepressant treatment modalities, including cognitive behavior therapy (CBT), antidepressant pharmacotherapies, and deep brain stimulation. Using a nonrandomized design, the authors previously compared changes following CBT or paroxetine in depressed patients. In this study, the authors report changes in fluorine-18-fluorodeoxyglucose PET in responders to CBT or venlafaxine during a randomized controlled trial.

METHODS

Subjects meeting DSM-IV-TR criteria for a major depressive episode and a diagnosis of a major depressive disorder received a fluorine-18-fluorodeoxyglucose PET scan before randomization and after 16 weeks of antidepressant treatment with either CBT (N=12) or venlafaxine (N=12). Modality-specific and modality-independent regional brain metabolic changes associated with response status were analyzed.

RESULTS

Response rates were comparable between the CBT (7/12) and venlafaxine (9/12) groups. Response to either treatment modality was associated with decreased glucose metabolism bilaterally in the orbitofrontal cortex and left medial prefrontal cortex, along with increased metabolism in the right occipital-temporal cortex. Changes in metabolism in the anterior and posterior parts of the subgenual cingulate cortex and the caudate differentiated CBT and venlafaxine responders.

CONCLUSIONS

Responders to either treatment modality demonstrated reduced metabolism in several prefrontal regions. Consistent with earlier reports, response to CBT was associated with a reciprocal modulation of cortical-limbic connectivity, while venlafaxine engaged additional cortical and striatal regions previously unreported in neuroimaging investigations.