Abnormal white matter integrity in Chinese young adults with first-episode medication-free anxious depression: a possible neurological biomarker of subtype major depressive disorder

Figures & data

Table 1 Demographics, clinical features, and DTI indices

Measure (mean ± SD)	Anxious depression (n=39)	Nonanxious depression (n=45)	Healthy controls (n=50)	Value	P-value
Age (years)	26.35±6.31	27.27±5.88	27.55±5.50	0.634	0.852*
Education (years)	15.84±3.12	15.21±3.29	15.52±3.23	0.413	0.664*
Gender (male/female)	16/23	18/27	21/29	3.347	0.181**
Duration of illness (months)	12.43±8.19	11.43±8.36	–	2.517	0.121***
HAMD	23.44±5.47	18.63±4.36	–	10.537	0.000***
Adjusted HAMDa	15.31±5.12	13.50±4.05	–	3.131	0.028***
HAMA	21.80±6.32	12.45±5.04	–	13.48	0.000***
FA (mm^2/s)	0.528±0.013	0.659±0.017	0.755±0.019	5.675	0.004*
MD (10^−4 mm^2/s)	8.581±0.217	8.743±0.231	8.622±0.224	1.012	0.365
RD (10^−4 mm^2/s)	6.232±0.233	5.751±0.265	5.244±0.262	5.041	0.010*
AD (10^−3 mm^2/s)	1.121±0.022	1.123±0.020	1.128±0.023	0.375	0.708

Notes:

* P-values for one-way ANOVA.

** P-values for chi-square test.

*** P-values for two-sample t-tests.

a Anxiety/somatization factor excluded.

Abbreviations: AD, axial diffusivity; ANOVA, analysis of variance; DTI, Diffusion Tensor Imaging; FA, fractional anisotropy; HAMA, Hamilton Rating Scale for Anxiety; HAMD, Hamilton Rating Scale for Depression; MD, mean diffusivity; RD, radial diffusivity.

Figure 1 TBSS analysis of FA and RD volumes revealed lower FA values (in red-yellow) and higher RD values (in yellow) in anxious MDD group when compared with the nonanxious group.

Notes: Results are overlaid on axial slices from the MNI standard brain at a permutation-based threshold of P<0.05 (FWE corrected). The background images are T1-weighted MNI template brains denoted with MNI coordinates. No regions of increased FA or decreased RD were found in the groups.
Abbreviations: FA, fractional anisotropy; FWE, family-wise error; MDD, major depressive disorder; MNI, Montreal Neurological Institute; RD, radial diffusivity; TBSS, tract-based spatial statistics.

Table 2 Locations of significant (P<0.05, FWE corrected) group differences between anxious and nonanxious depressions in FA and RD

Anxious vs nonanxious	Cluster index	Cluster voxels	MNI coordinates of peak side voxel			Mean FA or RD (post hoc)		Cohen’s d	Side	Anatomical regions
			x	y	z	Anxious (n=39)	Nonanxious (n=45)
FA	3	3,457	−23	−31	34	0.58	0.65	1.35	Bilateral Left	Forceps minor Superior longitudinal fasciculus, Unicinate fasciculus
	2	578	31	−60	13	0.57	0.63	1.78	Bilateral Left	Forceps major Superior longitudinal fasciculus
	1	102	−33	−51	27	0.47	0.54	0.89	Left	Superior longitudinal fasciculus
RD	1	12,541	−29	−3	22	5.78	5.25	0.83	Bilateral Left	Forceps major, forceps minor Superior longitudinal fasciculus

Notes: Anxious: anxious depression group; nonanxious: nonanxious depression group. The units of RD was 10⁻⁴ mm²/s.

Abbreviations: FA, fractional anisotropy; FWE, family-wise error; MNI, Montreal Neurological Institute; RD, radical diffusivity.

Figure 2 Correlation of FA and RD values with clinical features in pooled depression group.

Notes: (A) Mean FA values in cluster-1 and HAMA total scores (r=−0.563, P<0.001). (B) Mean FA values in cluster-3 and HAMA total scores (r=−0.497, P<0.001). (C) Mean RD values in cluster-1 and HAMA total scores (r=0.429, P<0.001). (D) Mean FA values in cluster-1 and adjusted HAMD-17 scores (r=−0.446, P<0.001). (E) Mean FA values in cluster-3 and adjusted HAMD-17 scores (r=−0.439, P<0.001). (F) Mean RD values in cluster-1 and adjusted HAMD-17 scores (r=0.355, P<0.001).
Abbreviations: FA, fractional anisotropy; HAMA, Hamilton Rating Scale for Anxiety; HAMD, Hamilton Rating Scale for Depression; RD, radial diffusivity.