Effects of a process-based cognitive training intervention for patients with stress-related exhaustion

Figures & data

Table 1. Diagnostic criteria for exhaustion disorder according to the Swedish National Board of Health and Welfare.

A. Physical and mental symptoms of exhaustion with minimum of 2 weeks duration. The symptoms have developed in response to one or more identifiable stressors which have been present for at least 6 months.

B. Markedly reduced mental energy, which is manifested by reduced initiative, lack of endurance or increase of time needed for recovery after mental efforts.

C. At least four of the following symptoms have been present most of the day, nearly every day, during the same 2-week period:

1. Persistent complaints of impaired memory or concentration.

2. Markedly reduced capacity to tolerate demands or to work under time pressure.

3. Emotionally instability or irritability.

4. Disturbed sleep.

5. Persistent complaints of physical weakness or fatigue.

6. Physical symptoms such as muscular pain, chest pain, palpitations, gastrointestinal problems, vertigo or increased sensitivity to sounds.

D. The symptoms cause clinically significant distress or impairment in occupational, social or other important areas of functioning.

E. The symptoms are not due to the direct physiological effects of a substance (e.g. drug abuse, medication) or a general medical condition (e.g. hypothyroidism, diabetes, infectious disease).

F. If criteria for major depressive disorder, dysthymic disorder or generalized anxiety disorder are met, ED is set as co-morbid condition.

All capital letters must be fulfilled for the diagnosis.

Table 2. Sample characteristics.

	Training group (n = 27)		Control group (n = 32)
Measure	Mean	SD	Mean	SD	p
Age	44.74	9.11	41.69	7.88	0.17^a
Verbal ability	21.15	5.19	23.50	3.51	0.04^a
SMBQ	5.11	0.84	4.84^c	1.03	0.28^a
HAD depression	7.11	2.68	7.36^c	3.61	0.77^a
HAD anxiety	11.00	2.76	9.63^c	3.91	0.14^a
	n	%	n	%
Sex					0.04^b
Women	20	74	30	94
Men	7	26	2	6
Education level					0.15^b
Elementary school	3	11	0	0
High school	9	33	12	37.5
University	15	56	20	62.5

Significant group differences are in bold. SMBQ = Shirom–Melamed Burnout Questionnaire. HAD = Hospital Anxiety and Depression Scale.

^aBased on independent samples t-test.

^bBased on Pearson's Chi-square test.

^cn = 31.

Table 3. Group means, standard deviations and interaction effect statistics on criterion-, near transfer- and far transfer tests.

	Training group		Control group		ANCOVA Group × Time
Measure	T1	T2	T1	T2	F	p
Criterion test
Letter memory running span	2.30 (1.64)	4.72 (1.86)	2.24 (1.63)	2.37 (1.84)	F(1, 54) = 22.00	< 0.001	0.29
Near transfer tests
3-back	20.28 (6.00)	25.93 (5.61)	23.42 (5.96)	24.59 (5.57)	F(1, 54) = 7.43	0.01	0.12
Inhibition cost	31.50 (10.90)	24.40 (8.18)	27.33 (10.82)	24.07 (8.12)	F(1, 54) = 2.67	0.11	0.05
Shift cost	49.96 (26.97)	43.30 (25.76)	46.97 (26.79)	41.63 (25.59)	F(1, 54) = 0.03	0.87	0.00
Digit span forwards	7.05 (2.22)	7.59 (1.90)	7.21 (2.21)	6.97 (1.88)	F(1, 54) = 3.03	0.09	0.05
Digit span backwards	6.72 (2.17)	7.34 (1.89)	5.99 (2.16)	6.42 (1.87)	F(1, 54) = 0.14	0.71	0.00
Letter-number sequencing	10.14 (2.61)	10.75 (2.31)	10.35 (2.59)	9.91 (2.30)	F(1, 54) = 2.14	0.15	0.04
Recall of concrete nouns	52.39 (10.30)	57.05 (12.27)	53.05 (10.24)	51.97 (12.19)	F(1, 54) = 4.57	0.04	0.08
Far transfer tests
Digit symbol	53.36 (11.06)	59.27 (13.03)	54.58 (10.98)	58.12 (12.94)	F(1, 54) = 1.66	0.20	0.03
Raven's matrices	6.75 (2.66)	7.74 (2.42)	7.12 (2.64)	5.91 (2.40)	F(1, 54) = 6.80	0.01	0.11

Means and standard deviations are adjusted for age, sex and verbal ability. Significant Group × Time interaction effects are in bold.

Figure 1. Effect sizes in Cohen's d (M_post − M_pre)/√[( + )/2] for all cognitive tests, based on pre-test to post-test change for the training group and the control group, respectively. Positive values represent an improvement. Significant interaction effects are denoted *p < 0.05; **p < 0.01; ***p < 0.001.

Table 4. Group means, standard deviations and interaction effect statistics on self-report forms regarding subjective cognitive complaints.

	Training group			Control group			ANCOVA Group × Time
Measure	n	T1	T2	n	T1	T2	F	p
6-QEMP	26	3.47 (0.59)	3.01 (0.72)	17	3.48 (0.60)	3.51 (0.74)	F(1, 38) = 6.32	0.02	0.14
PRMQ Prospective	24	26.27 (6.71)	23.24 (6.41)	17	26.91 (6.82)	25.95 (6.52)	F(1, 36) = 2.73	0.11	0.07
PRMQ Retrospective	24	20.56 (6.81)	19.58 (6.07)	17	22.28 (6.93)	22.06 (6.18)	F(1, 36) = 0.51	0.48	0.01

Means and standard deviations are adjusted for age, sex and verbal ability. Significant Group × Time interaction effects are in bold. 6-QEMP = 6-item Questionnaire of Everyday Memory Problems; PRMQ = Prospective and Retrospective Memory Questionnaire.

Figure 2. Effect sizes in Cohen's d (M_post − M_pre)/√[( + )/2] for the measures of subjective cognitive complaints, based on pre-test to post-test change for the training group and the control group, respectively. Positive values represent an improvement. 6-QEMP = 6-item Questionnaire of Everyday Memory Problems; PRMQ = Prospective and Retrospective Memory Questionnaire. Significant interaction effects are denoted *p < 0.05.