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Relapse in major depression linked to brain structures that regulate emotions

Researchers found that relapse in major depressive disorder was associated with morphologic changes in brain regions that regulate emotions and control cognition.

“Despite intense research on the clinical correlates of morphologic brain alterations in patients with MDD, longitudinal studies in well-characterized samples are needed to gauge neurobiological changes due to relapse,” Dario Zaremba, MSc, department of psychiatry, University of Münster, Germany, and colleagues wrote. “Structural neuroimaging techniques may provide insights into the underlying neural mechanisms of relapse. In the long term, understanding the neuronal correlates could support prognosis of relapse and thus improve maintenance treatment in patients with recurrent MDD.”

In their longitudinal case-control study, researchers used structural MRI to determine morphologic brain changes relating to relapse in 64 patients with acute major depression at baseline compared with 59 matched healthy controls. Depending on the course of illness between scans, they divided patients into groups with no relapse (n = 23) or with at least one additional episode (n = 37). The investigators analyzed imaging scans of whole-brain gray matter volume and cortical thickness of the anterior cingulate cortex, orbitofrontal cortex, middle frontal gyrus and insula at baseline and after 2 years. They also controlled for age and total intracranial volume.

Between baseline and follow-up, depressed patients who relapsed showed a major decline in the insular volume (95% CI, –0.063 to –0.002; P = .04) and dorsolateral prefrontal volume (95% CI, –0.113 to –0.045; P < .001). In contrast, patients who did not relapse and healthy controls showed no significant change in gray matter volume in these regions. In patients without relapse and healthy controls, cortical thickness increased in the anterior cingulate cortex (P = .005) and orbitofrontal cortex (P = .003) from baseline to follow-up, but there was no significant change in those who relapsed.

“Observed cortical changes from baseline to follow-up affected brain structures that are crucial for regulation of emotions and thus need to be prevented,” Zaremba and colleagues wrote. “Our results illustrate the negative association of relapse with morphologic brain alterations and might be a step to guide future prognosis and maintenance treatment in patients with recurrent MDD.”

These findings offer important information on how these brain regions in the early stages after an index episode of mental illness can potentially predict its course, Mary L. Phillips, MD, department of psychiatry, University of Pittsburgh, wrote in a related comment.

“Identifying these neural markers can, in turn, provide neural targets for interventions — perhaps even neuromodulation interventions — to combat underlying disease processes associated with gray matter reductions in these regions in vulnerable individuals,” Phillips wrote. “At a broader level, in a climate where the role of neuroimaging techniques in psychiatry remains unrealized, this study highlights the potential real-world utility of these techniques as clinical tools to provide information that can considerably influence long-term treatment choices to improve clinical outcomes for many people with MDD.” – by Savannah Demko

Disclosures: Zaremba reports no relevant financial disclosures. Please see the full study for all other authors’ relevant financial disclosures. Phillips reports no relevant financial disclosures.