Perceived stress, disturbed sleep, and cognitive impairments in patients with work-related stress complaints: a longitudinal study

Figures & data

Table 1. Demographic and clinical characteristics of the sample.

	Baseline	Follow-up
	(n = 60)	(n = 57)
Sex (male)	16%	16%
Age in years at baseline (min–max)	44.3 (28.6–61.3)	44.4 (28.6–61.3)
Education
Nine-year compulsory schooling	5.0%	5.3%
Upper secondary or vocational education	36.7%	35.1%
Bachelor or equivalent	46.7%	47.4%
Master or equivalent	11.7%	12.3%
Stress-related sick-leave in the last 3 months^a	78.3%	17.5%
Unemployed	0%	24.6%
Questionnaires: mean (SD)
The 10-item Perceived Stress Scale	24.5 (5.0)	15.8 (6.5)
Pittsburgh Sleep Quality Index	9.8 (3.8)	6.2 (3.7)
The Cognitive Failures Questionnaire	54.4 (14.1)	39.6 (14.5)
Neuropsychological testing
Prospective memory	49.7 (22.7)	61.0 (21.6)
Processing speed	98.2 (11.4)	105.2 (12.4)

^a Self-reported sick-leave (>1 week) due to work-related stress.

Table 2. Linear regression analyses with change in perceived stress (PSS) and sleep quality (PSQI) as predictors of change in processing speed and prospective memory.

					PSS and PSQI
Change in	PSS alone	PSS adjusted for PSQI	PSQI alone	PSQI adjusted for PSS	Adjusted R^2	MSE
Processing speed	β = 0.36*	β = 0.34*	β = 0.38	β = 0.02	0.08	58.96
	(0.10, 0.61)	(0.04, 0.64)	(−0.31, 1.06)	(−0.72, 0.75)
Prospective memory	β = 0.46	β = 0.32	β = 1.03	β = 0.68	0.00	403.01
	(−0.21, 1.13)	(−0.45, 1.10)	(−0.69,  2.75)	(−1.23, 2.60)

MSE: mean square error.

The 95% CI is shown in parenthesis.

* p < .05.

Table 3. Within-person effects of PSS-10 and PSQI – alone and combined – on concurrent change in CFQ.

	b	95% CI	p Value	Adj. R squared	MSE
PSS-10 alone	1.79	1.68, 1.91	<.001	0.95	0.05
PSS-10 adjusted for PSQI	1.36	0.82, 1.91	<.001	0.95	0.04
PSQI alone	5.43	5.02, 5.85	<.001	0.93	0.07
PSQI adjusted for PSS-10	1.32	−0.37, 3.02	.126	0.95	0.04

PSS-10: Perceived Stress Scale; PSQI: Pittsburgh Sleep Quality Index; MSE: mean square error.

The estimates are adjusted for the between-person effects.

Table 4. Within-person effects of perceived stress (PSS) and sleep quality (PSQI) – alone and combined – on subsequent (lagged) change in cognitive complaints (CFQ).

	b	95% CI	p Value	Adj. R squared	MSE
PSS lag alone	0.35	0.18, 0.53	<.001	0.72	46.09
PSS lag adjusted for PSQI	0.31	0.11, 0.51	.003	0.72	45.66
PSQI lag alone	0.46	0.12, 0.80	.008	0.71	48.30
PSQI lag adjusted for PSS	0.30	−0.09, 0.69	.134	0.72	45.66

Figure 1. The hypothesized relationship between work-related stress, sleep disturbances, and cognitive impairments.