Occupational stress is associated with sex and subregion specific modifications of the amygdala volumes

Figures & data

Table 1. Demographic data.

Variables	Female						Male
	Patients with ES		Controls				Patients with ES		Controls
	N		N		F-value	p-value	N		N		F-value	p- value
Age	36	35.42 (5.33)	38	32.62 (6.04)	2.511	.119	22	38.36 (6.67)	27	35 (5.99)	2.158	.152
MBI-GS	36	3.89 (0.61)	38	2.63 (0.48)	89.44	> 0.001	22	3.98 (0.47)	27	2.61 (0.35)	78.36	> 0.001
MADRAS	36	18.77 (5.69)	38	3.57 (2.67)	209.55	> 0.001	22	16.89 (5.95)	27	3.15 (3.34)	56.67	> 0.001
ICV	36	1455.37 (109.10)	38	1489.58 (99.65)	1.984	.163	22	1710.27 (77.01)	27	1749 (103.60)	0.903	.349

Patients with ES had higher MBI-GS scores compared to healthy controls independently of sex. Males had significantly larger ICV than females F(1.121) and controls F(1.121) had significantly larger ICV compared to patients with ES.

Abbreviations: ES: Exhaustion syndrome; MADRS: Montgomery-Åsberg Depression Rating Scale; MBI-GS: Maslach Stress- Burnout Inventory-General Survey; ICV: Intracranial volume.

Figure 1. Segmentation of hippocampal subfields and amygdala nuclei. T1-weighted scan with segmentations from a representative subject using the longitudinal stream. Results are displayed in coronal-, axial- and sagittal view and radiological convention (right = left).

Three radiological images lined horizontally showing the brain in coronal-, axial- and sagittal view. In each view, the right amygdala and hippocampus are selected with a box, showing a magnification in the lower part of the image which displays the results of a segmented amygdala and hippocampus with bright colors.

Table 2a. Volumes of the hippocampus subfields.

Group	L CA1	R CA1	L CA3	R CA3	L CA4	R CA4	L presubiculum	R presubiculum	L DG	R DG	L WH	R WH
Women with ES	318 ± 30	335 ± 31	103 ± 12	113 ± 15	123 ± 10	127 ± 12	149 ± 14	143 ± 14	143 ± 12	147 ± 14	3515 ± 205	3477 ± 273
Control women	319 ± 24	333 ± 26	105 ± 12	114 ± 11	126 ± 9	126 ± 9	153 ± 14	146 ± 15	147 ± 10	151 ± 10	3478 ± 273	3515 ± 205
Men with ES	355 ± 44	369 ± 39	113 ± 16	131 ± 17	136 ± 15	142 ± 15	173 ± 23	156 ± 14	160 ± 18	165 ± 18	3851 ± 338	3904 ± 287
Control men	345 ± 37	361 ± 40	110 ± 15	119 ± 18	133 ± 15	136 ± 16	169 ± 17	156 ± 16	155 ± 15	159 ± 17	3786 ± 321	3839 ± 306

No significant group difference was detected between female ES patients and female controls in the whole hippocampus, nor in any of the hippocampal subfields on the right or left side, [(Wilk’s lambda =0.653, F(27.47)=1.055; P=.624)]. Neither were any overall group difference among male groups (Wilk’s lambda was .519, F(18.39)=1.147, p=.378).

Volumes are expressed in mm³.

Abbreviations: ES: Exhaustion syndrome; L: left; R: right; CA: cornu amonis; DG: dentate gyrus; WH: whole hippocampus.

Table 2b. Volumes of the amygdala subfields.

Group	L lat Amy	R lat Amy	L med Amy	R med Amy	L ant Amy	R ant Amy	L basal Amy	R basal Amy	L CeA Amy	R CeA Amy	L WA	R WA
Women with ES	621 ± 55	621 ± 59	21 ± 5	21 ± 5	51 ± 5	51 ± 5	418 ± 37	419 ± 37	43 ± 6	51 ± 8	1669 ± 146	1767 ± 176
Control women	614 ± 46	617 ± 52	21 ± 5	20 ± 5	49 ± 5	50 ± 5	411 ± 33	413 ± 31	41 ± 4	45 ± 7	1639 ± 132	1730 ± 140
Men with ES	701 ± 60	733 ± 66	21 ± 5	26 ± 5	53 ± 6	64 ± 8	469 ± 40	493 ± 42	48 ± 7	53 ± 6	1834 ± 140	1942 ± 160
Control men	701 ± 80	730 ± 76	22 ± 5	26 ± 6	58 ± 8	64 ± 9	476 ± 55	499 ± 49	47 ± 6	58 ± 6	1935 ± 221	2056 ± 183

There was an overall group difference between the female groups, (Wilk’s lambda = 0.662, F(10.56) = 2.85, p=.006), with an enlargement of the left and right basal amygdala (p=.009 and .021, respectively), left and right lateral amygdala (p=.025 and p=.012), left and right central amygdala (p=.028 and <.001). Also, the WA was enlarged in patients on both sides (p<.001), (all calculated as ratios with ICV). No corresponding differences were detected in male groups (Wilk’s Lambda =0.657, F(10.38)=1.983, p=.063).

All volume values are expressed in mm³.

Abbreviations: ES: Exhaustion syndrome; Amy: amygdala; L: left; R: right; Lat: lateral; Med: medial; Ant: anterior nucleus; CeA: central; WA: whole amygdala.