1. The authors investigated the candidate neuroanatomic substrates underlyi
ng delusional thought disorder in old-aged depressed patients by using magn
etic resonance imaging (MRI), and examined the relationship between volumes
for individual brain structures and clinical correlates of particular rele
vance to depression: executive cognitive impairment and global severity of
depression.
2. MR morphometry was performed on nineteen deluded depressed patients and
26 non-deluded depressed patients, all older than 55 years of age. Subjects
were administered a neuropsychological test battery and measures of depres
sion.
3. The absolute volume of prefrontal cortex (PFC) was smaller in the delude
d depressed group than in non-deluded depressed group (131.79 +/- 37.26 mi
vs. 152.65 +/- 26.13 mi, p = 0.03); a difference that was statistically sig
nificant even after adjusting for the effect of whole brain volume (p = 0.0
1). No group differences were observed in the volumes of the basal ganglia,
the temporal lobes, the superior temporal gyri, the amygdala-hippocampal c
omplex, the lateral ventricles, or whole brain. The relative volume of PFC
correlated inversely and significantly with the index of Wisconsin Card Sor
ting Test (WCST) performance (r = -0.76, p < 0.01) in depressed patients.
4. PFC may be one of the candidate neuroanatomic substrates underlying delu
sional thought disorder in old-aged depression.