Autonomic dysregulation, cognition and fatigue in people with depression and in active and healthy controls: observational cohort study

BACKGROUND: Autonomic nervous system (ANS) dysregulation might be relevant to the pathophysiology of fatigue and cognitive impairment in depression and perhaps should be considered when making prescribing decisions. AIMS: To determine the relationship of self-reported ANS symptoms with fatigue, cognition and prescribed medication in people with a diagnosis of depression, in comparators without depression but with other mental health, neurodevelopmental or neurodegenerative disorders (active controls) and in healthy controls. METHOD: Cross-sectional analysis of an opportunistic sample from England. Self-reported data were collected on demographics, diagnosis, medication, ANS symptoms (Composite Autonomic Symptom Scale-31, COMPASS-31) and fatigue (Visual Analogue Scale for Fatigue, VAS-F). A subsample completed cognitive tests (THINC-it), including the subjective Perceived Deficits Questionnaire five-item version (PDQ-5). Spearman's correlation and mediation models were used to explore the relationship between COMPASS-31, VAS-F and PDQ-5 scores. RESULTS: Data were obtained for 3345 participants, 22% with depression. The depression group had significantly (P < 0.01) more severe autonomic dysregulation as measured by COMPASS-31 scores (median 30) than active (median 23) and healthy controls (median 10). The depression group had significantly higher symptom severity (P < 0.01) than both control groups on the VAS-F and PDQ-5. Overall, there was a significantly positive correlation (P < 0.01) between COMPASS-31, VAS-F scores (Spearman's rho r(s) = 0.44) and PDQ-5 scores (r(s) = 0.56). COMPASS-31 scores mediated greater symptom severity on the VAS-F and PDQ-5 for those with depression. COMPASS-31 scores remained significantly different between the depression group and both control groups independently of medication. CONCLUSIONS: People with a diagnosis of depression report worse fatigue and cognition than active and healthy comparators; this appears to be mediated by ANS dysregulation.