Relationship between subjective and objective fatigue and sleep characteristics in individuals with anxiety and mood...

Fatigue and sleep disturbances are important symptoms of anxiety and mood disorders (AMD). Studies about the relationship between these variables usually rely on self-report assessments. Therefore, the aim of our exploratory study was to investigate the independent correlations between subjective and objective fatigue and sleep characteristics in individuals with AMD.

In sum, 233 individuals with AMD attending a stress-related disorders day care unit (78.5 % females, mean age 39.0 years old) participated in a cross-sectional study. Participants completed the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, Multidimensional Fatigue Inventory-20, and Pittsburgh Sleep Quality Index self-report questionnaires, as well as an exercise capacity workload test for assessing objective fatigue and polysomnography monitoring for evaluation of sleep structure.

In individuals with AMD, exercise capacity workload was associated with lower percent of stage 1 sleep (β = - 0.17, p = 0.006), REM latency (β = -0.13, p = 0.042), and wake after sleep onset (β = -0.12, p = 0.039). General fatigue was associated with a higher percent of body movements (β = 0.12, p = 0.047), as well as mental fatigue was associated with a higher percent of body movements (β = 0.13, p = 0.029), and a higher score on the PSQI (β = 0.21, p = 0.002).

Objective sleep characteristics were associated with objective assessment of fatigue, while subjective sleep quality was associated with subjectively assessed mental fatigue.