Caudate volume measurement in older adults with bipolar disorder.

Background Decreased caudate volumes have been noted in unipolar depressed subjects, especially in the elderly and those with cognitive impairment. No differences have been noted in initial studies of multi-aged bipolar subjects; however, this region has not been examined in older bipolar subjects. Methods We examined the caudate nuclei volumes of 36 older bipolar subjects (mean age 58) and 35 older controls (mean age 62) using logistic regression analyses to control for age and gender differences. Differences between late- and early-onset (age-of-onset before age 45) bipolar subjects were also examined, as well as the effect of length of illness. Results The right caudate was noted to be smaller in older bipolar subjects compared with older controls when controlled for sex and age (p = 0.0448). No differences were noted in overall brain volume nor lateral ventricular volume between the bipolar and control subjects. Late-onset bipolar subjects had a decrease in brain volume (p = 0.035) compared with early-onset bipolar subjects. Late-onset bipolar subjects had a decrease in the right (p = 0.044) and total (p = 0.04) caudate size compared with older controls. Conclusions Right caudate volume is decreased in older bipolar subjects compared to controls. Bipolar subjects with late-onset illness have significantly decreased right and total caudate volumes compared to controls. This is affected by neither the length of illness nor the age of onset. Late-onset bipolar subjects have decreased total brain volume compared with early-onset bipolar subjects. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]