Background: Insomnia-type sleep disturbances are frequent among patients suffering from stress-related exhaustion disorder. However, clinical observations indicate that a subgroup suffer from sleep lengths frequently exceeding 9 hours, coupled with great daytime sleepiness.
Aims: The aim of the present study was to investigate differences in socio-demographic variables, use of medications, sleep parameters, anxiety, depression and fatigue, between individuals with varying sleep lengths, in a sample of 420 Swedish patients (mean age 42 ± 9 years; 77% women) referred to treatment for exhaustion disorder. Patients were allocated to the groups: "never/seldom ≥ 9 hours" (n = 248), "sometimes ≥ 9 hours" (n = 115) and "mostly/always ≥ 9 hours" (n = 57), based on their self-rated frequency of sleep lengths ≥ 9 hours.
Methods: The design was cross-sectional and data was collected by means of questionnaires at pre-treatment.
Results: Univariate analyses showed that patients in the "mostly/always ≥ 9 hours" group were more often on sick leave, and reported more depression and fatigue, better sleep quality and more daytime sleepiness, than patients in the other groups. Multivariate analyses showed that these patients scored higher on measures of fatigue than the rest of the sample independently of gender, use of antidepressants, sick leave, depression and quality of sleep.
Conclusions: Patients suffering from exhaustion disorder and reporting excessive sleep seem to have a generally poorer clinical picture but better quality of sleep than their counterparts with shorter sleep lengths. The mechanisms underlying these differences, together with their prognostic value and implications for treatment remain to be elucidated in future studies.
Keywords: Depression; Sleep; Stress; Stress-related exhaustion.