Delineation of early and later adult onset depression by diffusion tensor imaging.
BACKGROUND
Due to a lack of evidence, there is no consistent age of onset to define early onset (EO) versus later onset (LO) major depressive disorder (MDD). Fractional anisotropy (FA), derived from diffusion tensor imaging (DTI), has been widely used to study neuropsychiatric disorders by providing information about the brain circuitry, abnormalities of which might facilitate the delineation of EO versus LO MDD.


METHODS
In this study, 61 pairs of untreated, non-elderly, first-episode MDD patients and healthy controls (HCs) aged 18-45 years old received DTI scans. The voxel-based analysis method (VBM), classification analysis, using the Statistical Package for the Social Sciences (SPSS), and regression analyses were used to determine abnormal FA clusters and their correlations with age of onset and clinical symptoms.


RESULTS
Classification analysis suggested in the best model that there were two subgroups of MDD patients, delineated by an age of onset of 30 years old, by which MDD patients could be divided into EO (18-29 years old) and LO (30-45 years old) groups. LO MDD was characterized by decreased FA, especially in the white matter (WM) of the fronto-occipital fasciculus and posterior limb of internal capsule, with a negative correlation with the severity of depressive symptoms; in marked contrast, EO MDD showed increased FA, especially in the WM of the corpus callosum, corticospinal midbrain and inferior fronto-occipital fasciculus, while FA of the WM near the midbrain had a positive correlation with the severity of depressive symptoms.


CONCLUSIONS
Specific abnormalities of the brain circuitry in EO vs. LO MDD were delineated by an age of onset of 30 years old, as demonstrated by distinct abnormal FA clusters with opposite correlations with clinical symptoms. This DTI study supported the evidence of an exact age for the delineation of MDD, which could have broad multidisciplinary importance.


BACKGROUND
ClinicalTrials.gov NCT00703742.
Department of Psychiatry, First Affiliated Hospital of Kunming Medical University, Kunming, PR China.
Yuqi
Y
Cheng
Department of Internal Medicine, First Affiliated Hospital of Kunming Medical University, Kunming, PR China.
Jian
J
Xu
Magnetic Resonance Imaging Center, the First Hospital of Kunming City, Kunming, PR China.
Hongjun
H
Yu
Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, PR China.
Binbin
B
Nie
Department of Psychiatry, First Affiliated Hospital of Kunming Medical University, Kunming, PR China.
Na
N
Li
Magnetic Resonance Imaging Center, the First Hospital of Kunming City, Kunming, PR China.
Chunrong
C
Luo
Magnetic Resonance Imaging Center, the First Hospital of Kunming City, Kunming, PR China.
Haijun
H
Li
Department of Psychiatry, First Affiliated Hospital of Kunming Medical University, Kunming, PR China.
Fang
F
Liu
Department of Psychiatry, First Affiliated Hospital of Kunming Medical University, Kunming, PR China.
Yan
Y
Bai
Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, PR China.
Baoci
B
Shan
Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, PR China.
Lin
L
Xu
Department of Psychiatry, First Affiliated Hospital of Kunming Medical University, Kunming, PR China.
Xiufeng
X
Xu
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D016880:Anisotropy; D001921:Brain / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology / Q000523:psychology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult