Neuroimaging biomarkers distinguishing medication-naïve adolescents with major depressive disorder and bipolar disorder during depressive episodes.

BACKGROUND

The adolescent period represents a critical window of heightened vulnerability for the onset of major depressive disorder (MDD) and bipolar disorder (BD). Nevertheless, the neuro-metabolic abnormalities in adolescents with MDD and BD remain incompletely understood, and the early differentiation between MDD and BD in depressive episodes continues to pose significant clinical challenges.

METHOD: This study involved the recruitment of 60 adolescent MDD, 50 adolescent BD patients in depressed episodes, and 48 demographically matched healthy controls (HCs). Proton magnetic resonance spectroscopy (1H-MRS) was used to measure N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine (Cr) in the prefrontal white matter (PWM), putamen, and thalamus.

RESULTS

The results showed that both MDD and BD in depressive episodes exhibited extensive neurometabolic differences compared to HCs, and post hoc comparisons between MDD and BD revealed that adolescent patients with BD had higher left Putamen NAA/Cr ratios (P = 0.002) and lower left Thalamus NAA/Cr ratios (P = 0.018) compared to MDD. By developing a multivariate logistic regression model based on the NAA/Cr ratios of these two brain regions, an ROC curve was constructed (AUC=0.735), which can to some extent distinguish BD in depressive episodes from MDD.

CONCLUSION

Adolescent MDD patients and BD patients exhibit both similarities and differences in neurometabolism. The neurometabolic differences in left Putamen NAA/Cr ratios and left Thalamus NAA/Cr ratios between adolescent MDD patients and BD patients in depressive episodes may help in identifying adolescent BD patients early through 1H-MRS.