A quantitative magnetic resonance imaging study of caudate and lenticular nucleus gray matter volume in primary unipolar major depression: relationship to treatment response and clinical severity.

The authors investigated whether there were differences in caudate and lenticular nucleus volumes in depressed patients relative to comparison subjects, and whether differences in basal ganglia volume were associated with treatment response to fluoxetine. Brain magnetic resonance images were obtained from 38 unipolar depressed patients and 20 matched comparison subjects. Patients were divided into groups of 'responders' and 'non-responders' based on change in the 17-item Hamilton Depression Rating Scale (HDRS) score after a 10-week open trial of fluoxetine, 20 mg/day. There were no group mean differences in caudate and lenticular nucleus volumes between patients and comparison subjects. Female treatment responders tended to have larger caudate nucleus volumes than male 'responders', and also larger right caudate nucleus volumes than their female 'non-responder' counterparts. Baseline HDRS scores correlated negatively with left caudate nucleus volume in depressed patients. Thus, in mild to moderately depressed patients, we were unable to find differences in caudate and lenticular nucleus-gray matter volumes relative to comparison subjects. One possible reason is that caudate nucleus-gray matter volume and severity of depression are inversely correlated, suggesting that severity of depression may be an important covariate when comparing caudate volumes in depressed patients and control subjects.

A quantitative magnetic resonance imaging study of cerebral and cerebellar gray matter volume in primary unipolar major depression: relationship to treatment response and clinical severity.

The authors investigated whether there were differences in cerebral and cerebellar gray and white matter volumes in depressed patients compared to controls, and whether this was associated with treatment response to fluoxetine. Brain magnetic resonance images were obtained from 38 unipolar depressed patients and 20 age, gender, and educationally matched comparison subjects. Patients were divided into groups of "responders" and "nonresponders" based on change in 17-item Hamilton Depression Rating Scale (HDRS) after an 8-week standardized trial of fluoxetine, 20 mg/day. There were no group mean differences in cerebral or cerebellar tissue volumes between patients and controls, or responders and nonresponders. For nonresponders to fluoxetine treatment, cerebral and cerebellar gray matter volume, and total cerebellar tissue volume decreased as baseline HDRS increased. The results suggest an association between gray matter volume and severity of illness in nonresponders to fluoxetine treatment.

Basal ganglia choline levels in depression and response to fluoxetine treatment: an in vivo proton magnetic resonance spectroscopy study.

We have investigated proton magnetic resonance spectra of the basal ganglia in 41 medication-free outpatients with major depression, prior to starting an 8-week standardized trial of open-label fluoxetine, and 22 matched comparison subjects. Upon completing the trial, depressed subjects were classified as treatment responders (n = 18) or nonresponders (n = 23), based on changes in the Hamilton Depression Rating Scale. Depressed subjects had a lower area ratio of the choline resonance to the creatine resonance (Cho/Cr) than comparison subjects. This statistically significant difference between the depressed subjects and comparison subjects was more pronounced in the treatment responders than in the nonresponders. There were no differences in the relative volumes of gray matter or white matter in the voxel used for proton spectroscopy in depressed subjects relative to comparison subjects. These results are consistent with an alteration in the metabolism of cytosolic choline compounds in the basal ganglia of depressed subjects and, in particular, those who are responsive to fluoxetine.