Relationship between Seasonal Affective Disorder and Fibromyalgia among Type 2 Diabetics: Moderating Role of Sleep Quality

Abstract

Type 2 diabetes is generally associated with depression and seasonal affective disorder. This study examined sleep quality, seasonal affective disorder, and fibromyalgia in demographic variables. Purposive sampling of 200 patients with type 2 diabetes was recruited from clinics and hospitals. Using the Pittsburgh Sleep Quality Index, the Seasonal Pattern Assessment Questionnaire, and the Fibromyalgia Rapid Screening Tool, researchers found that poor sleep quality is predictive of fibromyalgia and seasonal affective disorder, and that sleep quality moderates the effect of fibromyalgia on seasonal affective disorder, with higher levels of fibromyalgia related to higher levels of seasonal affective disorder among those with poor sleep quality. Additionally, sleep quality, fibromyalgia symptoms, and seasonal affective disorder differed significantly by gender, climatic zone, and vitamin D levels, suggesting that clinicians should consider focusing treatment strategies on sleep quality in patients with type 2 diabetes, fibromyalgia, and seasonal affective disorder.