Joel Yager, MD

Thinner medial orbitofrontal cortices are associated with first-episode depression and greater trait anxiety.

Preliminary studies have shown that several areas of the paralimbic cortex are thinner in depressed patients, but these patients were often taking antidepressants. These investigators examined paralimbic cortical thickness in 20 medication-naive, acutely ill, first-episode depressed patients; 20 medication-free patients recovered from a first episode of depression; and 31 healthy comparison subjects.

Examined areas encompassed orbitofrontal, cingulate, insular, parahippocampal, and temporopolar cortices. Tests included clinical ratings of mood, state anxiety, and trait anxiety and tests of intelligence, verbal and nonverbal memory, and executive function. Maps derived from magnetic resonance imaging were used to calculate cortical thickness of sulci and gyri.

These medication-free, first-episode patients showed no neuropsychological impairments. Both patient groups showed significantly thinner cortices than the healthy comparison group in left medial orbitofrontal cortex and greater thickness in left posterior cingulate cortex, left caudal anterior cingulate, and left temporal pole. No differences were seen between the two patient groups, suggesting that the findings were related to the trait of major depression and not the acutely depressed state. In analyses that controlled for depression ratings, trait anxiety scores (a proxy for mood regulation) were inversely associated with thickness of left medial orbitofrontal cortex, but only in the healthy comparison group.

Citation(s):

van Eijndhoven P et al. Paralimbic cortical thickness in first-episode depression: Evidence for trait-related differences in mood regulation. Am J Psychiatry 2013 Aug 9; [e-pub ahead of print].