Cognitive performance in patients with burnout, in relation to diurnal salivary cortisol

Figures & data

Table I.  Characteristics of the burnout group (n=65)

Characteristic	n (%)	Mean (SD)
Somatic disorders, total	17 (26)	–
Hypertension (treated)	6 (9)	–
Type II diabetes	2 (3)	–
Whiplash	2 (3)	–
Other^*	7 (11)	–
Medication
Antidepressants; SSRI, SNRI, or NaSSA^†	19 (29)	–
Anxiolytics or sleeping pills	10 (15)	–
Medication for somatic disorders^‡	13 (20)	–
No medication	36 (55)	–
Psychotherapy	27 (42)	–
Alcohol consumption
Low to moderate	63 (97)	–
High	2 (3)	–
Tobacco use, regular	10 (15)	–
Prime-MD
Major depression	13 (20)^¶	–
Slight depression	7 (11)^§	–
Anxiety disorder	7 (11)	–
Anxiety disorder + major depression	14 (21)^‖	–
Anxiety disorder + mild depression	3 (5)	–
Social phobia	1 (2)	–
MBI-GS, exhaustion score	–	4.6 (1.2)
SCL-90 subscales
Anxiety	–	1.6 (0.9)
Somatisation	–	1.3 (0.8)
Depression	–	1.9 (0.8)
BDI mean raw score	–	19.3 (8.7)
Severe depression	8 (12)	–
Moderate depression	31 (48)	–
Slight depression	15 (23)	–
Minimal depression	11 (17)	–

Prime-MD, Primary Care Evaluation of Mental Disorders (Spitzer et al. 1994); MBI-GS, Maslach Burnout Inventory-General Survey (Maslach et al. 1996); SCL-90, Symptom Checklist 90 (Derogatis 1992); BDI, Beck Depression Inventory (BDI) (Beck et al. 1988)

^* These subjects each had one of: thyroid disorder (treated), gluten intolerance, allergy, chronic bronchitis, recurrent diverticulitis, atrial fibrillation, slight B12 deficiency, and mineral deficiency (treated)

^† Selective serotonin reuptake inhibitor (SSRI), serotonin–norepinephrine reuptake inhibitor (SNRI), or noradrenergic and specific serotonergic antidepressant (NaSSA)

^‡ Mostly antihypertensive, antihyperlipidemic, and antidiabetic drugs, beta blockers, vitamin or mineral supplements, or weight control drugs

^¶ Two subjects also fulfilled the criteria for somatoform syndrome NUD

^§ One subject also fulfilled the criteria for somatoform syndrome NUD

^‖ One subject also fulfilled the criteria for obsessive–compulsive disorder.

Table II.  Neuropsychological test raw scores for patients with burnout disorder and healthy referents.

Cognitive domain and test	Patients (n = 65)		Referents (n = 65)		ANOVA, Group
	Mean	SD	Mean	SD	F^*	p^†	ηp^2
Verbal intellectual ability
SRB:1 vocabulary	24.2	3.7	24.2	3.8	1.96	0.16^D,E	–
Memory
Cronholm-Molander verbal memory, immediate recall	20.9	4.4	21.9	4.8	6.71	0.011^D,E	0.051
Cronholm-Molander verbal memory, delayed recall	17.2	5.1	17.9	5.4	5.50	0.021^D,E	0.042
Austin maze, total errors^‡	38.1	22.7	39.3	19.9	0.18	0.67^A,G	–
Austin maze, total performance time (s)^‡	308	114	316	128	4.52	0.036^A,D,E,G	0.035
Incidental learning WAIS-R NI, number correct^¶	6.8	2.1	6.6	1.6	0.10	0.75^A	–
Sustained attention and processing speed
WAIS-R Digit Symbol	53.1	11.1	58.4	11.1	9.61	0.002^A,E,G	0.072
APT k-test,^§ d'	4.10	0.45	4.01	0.52	1.07	0.30^A	–
APT k-test, β^‖	− 0.62	0.70	− 0.72	0.65	0.82	0.37^G	–
APT k-test, RT level for correct responses, left part of screen (ms)^‡	1138	275	1111	236	0.04	0.84^A,G,P	–
APT k-test, RT level for correct responses, center part of screen (ms)^‡	993	268	961	193	0.03	0.85^G,P	–
APT k-test, RT level for correct responses, right part of screen (ms)^‡	1242	308	1266	282	0.27	0.61^A,E,G	–
APT k-test, search strategy^#	0.56	0.10	0.59	0.09	3.21	0.075	–
APT k-test, error ratio (%)^‡	2.2	2.6	2.8	3.1	1.33	0.25	–

^* df ranged from [1,123] to [1,127], except for Incidental learning WAIS-R NI [1,89]

^† Univariate ANOVA p-values for between-group comparisons, corrected for age (A), Symptom Checklist-90 depression score (D), level of education (E), gender (G), and medication with psychopharmacological drugs (P) in case p < 0.20 for each covariate

^‡ A lower score signifies better performance

^¶ Reference data were available only for women; consequently, comparison data is given for women only (n = 46 per group, the covariate gender excluded)

^§ n = 64 in the patient group; for one case, the k-test data was excluded due to the patient misunderstanding the instructions

^‖ Qualitative variable; a negative β indicates that false rejection (missed ‘k's) was more common than false alarms (alarms when k not present)

^# Qualitative variable; a lower value indicates a more sequential search strategy, while a higher value indicates a more global search strategy.

Figure 1 Salivary cortisol concentrations (medians and quartiles) among patients with burnout (broken line with triangles; n = 50–55) and reference persons (solid line with squares; n = 50–55), at awakening, 30 min after awakening, and at 9 p.m., on ordinary weekdays, and among burnout patients after dexamethasone ingestion (broken line with circles; n = 41). Statistical significance for group differences (ordinary weekdays) in univariate ANOVA: *p < 0.001; n.s. p>0.05.

Table III.  Diurnal salivary cortisol concentrations and computed index values (medians and quartiles) on a normal weekday among patients with burnout disorder and healthy referents, and after dexamethasone treatment among patients with burnout disorder.

Cortisol measure (values in nmol/L unless otherwise stated; n refers to number of participants in the burnout group with valid data)	Patients		Referents (n = 174)		ANOVA, Group
	Md	Q1/Q3	Md	Q1/Q3	F^*	p^*	ηp^2
Raw values
At awakening (n = 53)^‡	9.2	6.1/13.2	9.8	7.0/13.1	0.21	0.65	–
30 min after awakening (n = 50)^¶	14.4	9.7/21.6	14.1	10.1/18.3	0.09	0.77	–
At 9 p.m. (n = 55)^‖	1.3	1.0/1.7	2.1	1.6/3.1	28.05	< 0.001^D	0.111
After dexamethasone treatment (n = 41)
• at awakening^‖	0.8	0.4/1.1	–	–	–	–	–
• 30 min after awakening^∥	0.7	0.5/1.2	–	–	–	–	–
Indexes
Cortisol awakening response (CAR; n = 47)^§,^#
• absolute increase	4.2	− 0.9/8.7	4.4	− 0.3/8.4	0.09	0.77^A,G	–
• proportional increase (%)	53.5	− 6.1/112.6	49.2	− 2.3/111.5	0.04	0.84^G	–
Cortisol morning peak value (CMP; n = 56)	14.2	8.8/21.7	14.8	11.6/19.0	1.27	0.26	–
Cortisol decrease from morning (peak value) to evening (CR; n = 54)	− 12.6	− 19.0/ − 6.8	− 12.1	− 16.8/ − 9.0	2.22	0.14^D	–
Proportional cortisol decrease after dexamethasone treatment (n = 41) compared with the corresponding time points on a normal weekday
• at awakening (%)	− 90.9	− 95.1/ − 86.2	–	–	–	–	–
• 30 min after awakening (%)	− 93.9	− 96.9/ − 90.0	–	–	–	–	–

^* df ranged from [1,285] to [1,295]

^† Univariate ANOVA p-values for between-group comparisons, corrected for age (A), Symptom Checklist-90 depression score (D), gender (G), and medication with psychopharmacological drugs (P) in case p < 0.20 for each covariate

^‡ The median and Q1/Q3 values for the subsample of 41 subjects included in the DST analysis were identical to the values for the total burnout group

^¶ The values for the subsample of 41 burnout subjects included in the DST analysis were Md = 14.7; Q1/Q3 = 6.2/21.8

^§ Computed as the increase from the awakening value to the value 30 min after awakening

^# A negative CAR was found among 28% (n = 13/47) of the burnout subjects and among 26% (n = 46/174) of the referents

^‖ Most cortisol concentrations in the burnout group were below the detection limit (1.59 nmol/L) and are thus approximate.

Figure 2 Salivary cortisol concentrations (medians and quartiles) among patients with burnout, divided into group halves based on a median split of the z-score reaction time performance in the APT k-test (the subgroup performing above median shown as broken line with triangles, and below median as solid line with squares), at awakening (n = 27/25), 30 min after awakening (n = 23/26), and at 9 p.m. (n = 26/28). Statistical significance for group differences in univariate ANOVA: *p < 0.001; n.s. p>0.05.

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