• Systemic lupus erythematosus
• actigraphy
• sleep disturbances
• mood disorders

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can affect any organ of the body. Depression is one of the most frequent disorders in SLE, ranging from 17 to 75% of prevalence, although subtle neuropsychiatric syndromes like symptoms of depressive and anxiety axes are often considered as “non-neuropsychiatric SLE”. Recent data suggest SLE patients also suffer from sleep disturbances like frequent awakenings and unrestorative sleep, and worse sleep quality has been found to be a fellow traveller with this disease.
Relationship between depression and sleep disturbances has been established previously in other categories of patients, but only a few studies examined sleep disturbances with objective methods in SLE patients. Therefore, the aim of this study was to evaluate sleep in SLE patients in comparison with a cohort of age and sex-matched controls using actigraphy, that has been proved to be an efficient and reliable tool to identify sleep disturbances. The presence of mood disorders, temperament, health-related quality of life and subjective perception of sleep were evaluated with specific questionnaires: Beck Depression Inventory, Self Rating Anxiety Scale, Brief COPE, Pittsburgh Sleep Quality Index, Insomnia Severity Index, Perceived Stress Scale, Resilience Scale for adult, Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Scale, Brief TEMPS-M, Lupus QoL and Short Form Health survey 36 (in SLE patients and controls respectively).
The strongest predictors of the SLE group were mainly higher scores in Beck Depression Inventory and Self Rating Anxiety Scale index, lower Sleep Efficiency and greater Total Sleep Time.
Statistically significant differences were found between depressed SLE patients and non-depressed SLE patients in several parameters: burden to others Lupus QoL sub scale score, pain sub scale score, Perceived Stress Scale score, Functional Assessment of Chronic Illness Therapy (FACIT) fatigue scale score and body image sub scale. In fact, lower scores in FACIT fatigue scale, burden to others, pain and body image domains while Perceived Stress Scale score was higher in depressed SLE patients. In SLE group, fatigue, as measured by FACIT score, was strongly negative correlated with Beck Depression Inventory score and positively correlated with physical subscale score.
Within SLE groups with differentially analyzed two subgroups, fibromyalgic and non fibromyalgic patients, we identified a statistically significant difference was found in pain domain, with lower scores in fibromyalgic patients, while no significant difference was found between patients with joint involvement and patients without joint involvement, addressing fibromyalgia as the factor with greater impact over pain. Instead, SAS index was not correlated with objective indices of sleep disturbances, while it strongly correlated with subjective indices of sleep disorders (Pittsburgh Sleep Quality Index and Insomnia Severity Index, specifically).
In conclusion, SLE is a chronic disease that has great impact on mood and sleep quality and identification of this problems together with suggestion of therapeutic interventions that may improve the quality of life of these patients.