Clinically depressed adolescents have decreased functional connectivity between several brain regions involved in emotion processing, but increased connectivity between brain regions known to be involved in rumination, according to a new study in Psychiatry Research: Neuroimaging.

“The aim of the present study was to map the resting state functional connectivity using a seed-based correlation method in adolescent major depressive disorder patients,” explained study author Lee Moon-Soo, a professor at Korea University and associate editor of Clinical Psychopharmacology and Neuroscience.

“Based on previous studies, this study focused on the core regions of the frontolimbic circuit, especially the hippocampus and insula. To exclude the confounding effect of antidepressants and different clinical status, we included only first-episode, psychotropic drug-naive adolescents with major depressive disorder. We wanted to know what is the difference of resting state fMRI between normal healthy typically-developing controls and first onset adolescent patients with major depressive disorder.”

For their study, the researchers compared the brain structure of 23 adolescents diagnosed with first-episode depression to 27 non-depressed adolescents. They found that the depressed adolescents had an altered pattern of functional connectivity in several brain regions.

“Depressed adolescents showed changed functional connectivity in the brain even when they are in the first episode,” Lee told PsyPost.

“Adolescents with depression, prior to exposure to medication, display a decreased connectivity between several brain regions involved in emotion processing and regulation and emotional memory. An increased connectivity was also observed in brain regions that are known to be related to rumination, impaired concentration, and physiological arousal.”

In particular, the researchers found lower connectivity between the right amygdala and right superior frontal gyrus, and between the right hippocampus and a cluster that included the right insula and right middle frontal gyrus in depressed participants.

There was higher connectivity between the left insula and a cluster that included the bilateral middle frontal gyrus, right superior frontal gyrus, and right frontal pole, and between the left dorsal anterior cingulate cortex and a cluster that included the left insula.

“We are currently conducting a follow-up study. We want to know whether these functional changes in the brain could be reversed by the medical treatment. We believe that those functional changes might be reversible by the appropriate treatments,” Lee added.

“In addition, we also need to know the further differences in the depressed patients according to the subgroups. Depression can take many forms. For example, it would be quite meaningful to compare the patients who have suicidal ideation with the patients who do not have.”

The study, “Resting-state functional connectivity in medication-naïve adolescents with major depressive disorder“, was authored by Jeonho Lee, Mani N. Pavuluri, Ji Hyun Kim, Sangil Suh, Inseong Kim, and Moon-Soo Lee.