State-dependent and trait-related gray matter changes in nonrefractory depression.

Behavioral evidence suggests functional remission or recovery in nonrefractory depressive disorder after successful antidepressant therapy, but the effect of treatment on brain structures remains unclear. It is possible that some specific structural changes are trait-related, in addition to some state-dependent anatomical regions that could be normalized by medications. In the current study, 32 treatment-naïve nonrefractory depressive disorder patients and 34 matched healthy controls underwent structural MRI scans and a subgroup including 16 patients underwent the second scans after clinical recovery with antidepressant treatment. The statistical analysis of gray matter images showed that the state-dependent regions mainly comprised the key regions within the lateral default, dorsal attention, and frontoparietal networks, whereas the trait-related regions included the medial prefrontal cortex, right anterior insula, thalamus, right parahippocampal gyrus, and right middle occipital gyrus. Moreover, the gray matter changes in the left orbitofrontal cortex, right middle frontal gyrus, left inferior parietal lobule, thalamus, left precentral gyrus, left precuneus, and right middle occipital gyrus were significantly positively correlated with the durations of the current depressive episode. The current findings may not only shed new light on the neuronal effect of antidepressant on depression but also provide potential evidence of the relapse risks for the clinically recovered patients after antidepressant treatment.