“Our findings suggest that early adolescence is a particularly sensitive period for depressive symptoms to affect cortical surface area development and may provide a critical window for treatment of (subthreshold) depressive symptoms,” Lianne Schmaal, Ph.D., and colleagues wrote.
The study is part of the Orygen Adolescent Development Study, which is being conducted by Orygen, the National Centre of Excellence in Youth Mental Health based in Melbourne, Australia.
Cortical surface area is known to expand during adolescence, remain relatively stable in adulthood, and decrease with older age. The researchers collected structural MRI data from 149 adolescents from age 12 through 19. At each MRI visit, participants were asked about depressive symptoms, using the Center for Epidemiologic Studies Depression Scale (CES-D).
Three depressive symptom trajectories were identified among the participants: “low-stable” (n=97), a group with stable low levels of depression throughout the trial; “early-decreasing” (n=33), a group with moderate initial depressive symptoms that declined over time; and “late-increasing” (n=19), a group with increasing symptoms at each follow-up.
Females with early-decreasing symptoms showed lower anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC) surface area compared with females with stable low levels of depression and with increasing symptoms across adolescence. Males with low stable and late increasing symptoms showed an increase of right OFC surface area, whereas males with early decreasing symptoms showed no such surface area expansion over time.
The authors noted that because the trial did not include data beyond age 19, there is no way to know “whether the observed lower ACC and OFC surface area findings represent a delay in maturation, i.e., catching up when transitioning into adulthood, or whether these lower surface areas persist into adulthood.” Still, they added, “These findings may indicate that the experience of depressive symptoms early in adolescence, a critical period for surface area expansion, interrupts normal brain maturation of surface area.”
For related information, see the Psychiatric News article “Researchers Develop Composite Image of Brains of Youth With MDD.”
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