Groups did not differ significantly (p
> .05) on age, ethnicity, height, gender, educational level, or nature of medical illness (). Concomitant medications were common but similar in the two groups and in many cases included bronchodilators in the patients with asthma, analgesics in the patients with rheumatic diseases, and in some cases immunosuppressants. Detailed information on concomitant medications can be found in Brown et al
). Amygdala volume of corticosteroid-treated patients (n
= 15) was approximately 20% smaller on the left (771.8 ± 266.9 mm3
vs. 960.4 ± 358.2 mm3
) and 11% smaller on the right (768.5 ± 229.5 mm3
vs. 867.8 ± 281.1 mm3
) than control subjects (n
= 13), resulting in a significant between-group effect for volume (F
= 4.49, df
= 1,52, p
= .039) (). A significant between-side effect of amygdala volume observed (F
= .44, df
= 1,52, p
Characteristics of Corticosteroid-Treated Patients and Control Subjects
Left and right amygdala volumes in corticosteroid-treated patients and controls.
A total of 9 of 15 corticosteroid-treated participants had a current or past prednisone-induced mood disorder on structured clinical interview. Although amygdala volume was numerically large on the right (795.2 ± 244.2 mm3 vs. 738.0 ± 226.5 mm3) and left (838.5 ± 288.0 mm3 vs. 695.6 ± 288.8 mm3) in those with mood disorders secondary to corticosteroids, a significant between-group effect for volume was not observed (F = .807, df = 1, p = .387).
In control subjects, left and right amygdala volume correlated with each other (r = .864, p < .001). Age correlated significantly with right (r=−.573, p = .040) but not left (r=−.451, p = .122) amygdala volume. Young Mania Rating Scale scores showed a trend toward a significant correlation with right (r=−.511, p = .075) not but not left (r = −.437, p = .135) amygdala volume. Hamilton Rating Scale for Depression and BPRS scores did not correlate significantly with amygdala volume (r=−.453 to .270, p = .116 to .372). Rey Auditory Verbal Learning Test total scores showed a trend toward a significant correlation with left (r = −.508, p = .077) but not right (r=−.464, p = .110) amygdala volume. Hippocampal volume, NAA ratios, RAVLT delayed recall, Stroop Color Word Test, and Trails Making Test A and B did not correlate significantly with left or right amygdala volume (r=−.411 to .340, p = .163 to .941).
In the corticosteroid-treated patients, left and right amygdala volume correlated with each other (r = .587, p = .021). A significant correlation was also observed between length of corticosteroid therapy and right (r=−.597, p = .019) but not left (r = −.412, p = .127) amygdala volume (). Current corticosteroid dose did not correlate significantly with right (r = −.077, p = .786) or left (r = .132, p = .639) amygdala volume. Age did not correlate significantly with length of corticosteroid therapy (r = −.196, p = .484). Right hippocampal volume correlated with right amygdala volume (r = .554, p = .032), but left hippocampal volume did not correlate significantly with left amygdala volume (r = .311, p = .260). Age, NAA ratios, and RAVLT, Stroop Color Word Test, Trails Making Test A and B, HRSD, YMRS, and BPRS scores did not correlate significantly with amygdala volume (r=−.395 to .132, p = .145 to .999) in the corticosteroid-treated group.
Graph of right amygdala volume and time on corticosteroids (r=-0.597, p=0.019).