The relationship between sleep disturbance, symptoms and daytime functioning in psoriasis: a prospective study integrating actigraphy and experience sampling methodology.

OBJECTIVE/BACKGROUND: Sleep disturbance is common in individuals with psoriasis and appears to be related to both physical and psychological factors. We sought to examine whether psoriasis symptoms, night-time arousal and low mood predicted subsequent objective and self-reported sleep; and whether objective and self-reported sleep predicted next-day psoriasis symptoms and day-time functioning. PARTICIPANTS/METHODS: A total of 19 individuals (Female: 11 [57.9%], median age: 39 years) with chronic plaque psoriasis and poor sleep quality (mean Pittsburgh Sleep Quality Index, PSQI = 9.11) participated. Momentary assessments of psoriasis symptoms, mood and daytime functioning were completed at five pseudo-random intervals each day for 15 days using time-stamped digital diary entry. Objective sleep was estimated using wrist-worn actigraphy. Self-reported sleep and night-time arousal were assessed each morning using validated measures. RESULTS AND CONCLUSIONS: Two-level random intercept models showed that increased night-time arousal was associated with poorer diary-reported sleep. Neither self-reported nor objective sleep parameters were associated with daytime psoriasis symptoms in bi-directional analyses. Diary-reported sleep predicted next-day functioning, specifically sleepiness, concentration, and fatigue. Actigraphy-defined total sleep time predicted next-day fatigue. Night-time arousal is associated with poorer self-reported sleep in people with psoriasis, and sleep predicts next-day functioning. Contrary to our hypothesis, sleep disturbance does not appear to be associated with momentary assessments of psoriasis symptoms.