Regional brain metabolic changes in patients with major depression treatedwith either paroxetine or interpersonal therapy - Preliminary findings

Background: In functional brain imaging studies of major depressive disorde r (MDD), regional abnormalities have been most commonly found in prefrontal cortex, anterior cingulate gyrus, and temporal lobe. We examined baseline regional metabolic abnormalities and metabolic changes from pretreatment to posttreatment in subjects with MDD. We also performed a preliminary compar ison of regional changes with 2 distinct forms of treatment (paroxetine and interpersonal psychotherapy). Methods: Twenty-four subjects with unipolar MDD and 16 normal control subje cts underwent resting F 18 (F-18) fluorodeoxyglucose positron emission tomo graphy scanning before and after 12 weeks. Between scans, subjects with MDD were treated with either paroxetine or interpersonal psychotherapy (based on patient preference). while controls underwent no treatment. Results: At baseline, subjects with MDD had higher normalized metabolism th an controls in the prefrontal cortex land caudate and thalamus), and lower metabolism in the temporal lobe, With treatment, subjects with MDD had meta bolic changes in the direction of normalization in these regions. After tre atment, paroxetine-treated subjects had a greater mean decrease in Hamilton Depression Raring Scale score (61.4%) than did subjects treated with inter personal psychotherapy (38.0%), but both subgroups showed decreases in norm alized prefrontal cor tex (paroxetine-treated bilaterally and interpersonal psychotherapy-treated on the right) and left anterior cingulate gyrus meta bolism, and increases in normalized left temporal lobe metabolism. Conclusions: Subjects with MDD had regional brain metabolic abnormalities a t baseline that tended to normalize with treatment. Regional metabolic chan ges appeared similar with the Z forms of treatment. These results should be interpreted with caution because of study limitations (small sample size, lack of random assignment to treatment groups, and differential treatment r esponse between treatment subgroups).