Hippocampal and Left Subcallosal Anterior Cingulate Atrophy in Psychotic Depression

<div><p>Background</p><p>Psychotic depression is arguably the most diagnostically stable subtype of major depressive disorder, and an attractive target of study in a famously heterogeneous mental illness. Previous imaging studies have identified abnormal volumes of the hippocampus, amygdala, and subcallosal region of the anterior cingulate cortex (scACC) in psychotic depression, though studies have not yet examined the role of family history of depression in these relationships.</p><p>Methods</p><p>20 participants with psychotic depression preparing to undergo electroconvulsive therapy and 20 healthy comparison participants (13 women and 7 men in each group) underwent structural brain imaging in a 1.5 T MRI scanner. 15 of the psychotic depression group had a first-degree relative with diagnosed affective disorders, while the healthy control group had no first-degree relatives with affective disorders. Depression severity was assessed with the Hamilton Depression Rating Scale and duration of illness was assessed in all patients. Automated neural nets were used to isolate the hippocampi and amygdalae in each scan, and an established manual method was used to parcellate the anterior cingulate cortex into dorsal, rostral, subcallosal, and subgenual regions. The volumes of these regions were compared between groups. Effects of laterality and family history of affective disorders were examined as well.</p><p>Results</p><p>Patients with psychotic depression had significantly smaller left scACC and bilateral hippocampal volumes, while no group differences in other anterior cingulate cortex subregions or amygdala volumes were present. Hippocampal atrophy was found in all patients with psychotic depression, but reduced left scACC volume was found only in the patients with a family history of depression.</p><p>Conclusions</p><p>Patients with psychotic depression showed significant reduction in hippocampal volume bilaterally, perhaps due to high cortisol states associated with this illness. Reduced left scACC volume may be a vulnerability factor related to family history of depression.</p></div

Depressive symptoms related to low fractional anisotropy of white matter underlying the right ventral anterior cingulate in older adults with atherosclerotic vascular disease

We sought to characterize the relationship between integrity of the white matter underlying the ventral anterior cingulate (vAC) and depressive symptoms in older adults with atherosclerotic vascular disease (AVD), a condition associated with preferential degeneration of the white matter. The ventral anterior cingulate was defined as including white matter underlying ventral Brodmann Area 24 and Brodmann Area 25, corresponding with the subcallosal and subgenual cingulate respectively. This region of interest was chosen based on the preponderance of evidence that the white matter in the region plays a critical role in the manifestation of depressive symptoms. Participants had current unequivocal diagnoses of AVD and were between 55 and 90 years old. Fractional anisotropy (FA) was used as an index of white matter integrity and organization. Whole-brain mean diffusivity (MD) was used as an index of global white matter lesion burden. Depressive symptoms were measured using the Symptom Checklist-90-Revised (SCL-90-R) Depression Scale. Depressive symptoms were significantly related to low FA in the right vAC (r=-.356, DF=30, p=.045) but not the left vAC (r=.024, DF=30, p=.896) after controlling for total brain MD (a statistical control for global white matter lesion burden). Further, depressive symptoms were significantly related to low FA in the right vAC (r=-0.361, DF=31, p=.039), but not the left vAC (r=.259, DF=31, p=.145) when controlled for the contralateral vAC FA. The correlation coefficients for this follow-up analysis were found to be significantly different between left and right vAC (Z=2.310, p=.021).Poor white matter health in the vAC may be a biological mechanism for depressive symptoms in older adults with vascular disease. Further studies may corroborate that the right vAC plays a unique role in depressive symptom manifestation in cases where the white matter is preferentially affected, as is the case in AVD. This could lead to future targeting o

Comparison of psychotic depression group with healthy controls on brain volumetrics.

<p>Comparison of psychotic depression group with healthy controls on brain volumetrics.</p

Laterality effects on hippocampus and subcallosal ACC volumes in psychotic depression compared to age-matched healthy comparisons.

<p>Laterality effects on hippocampus and subcallosal ACC volumes in psychotic depression compared to age-matched healthy comparisons.</p

Demographic Comparison between Psychotic Depression and Healthy Control groups.

<p>Demographic Comparison between Psychotic Depression and Healthy Control groups.</p

Parcellations of the anterior cingulate cortex.

<p>Dorsal anterior cingulate cortex (ACC) shown in blue, rostral ACC in red, subcallosal ACC in green, subgenual ACC in yellow. Figure reprinted with permission from John Wiley and Sons, from McCormick et al., (2008), license number 3103240766914.</p