Association between chronic pruritus, depression, and insomnia: A cross-sectional study

Background: Skin diseases that cause chronic pruritus can have negative effects on a patient's quality of life. Objective: We evaluated the associations between chronic pruritus and psychological conditions including insomnia and depression. Methods: This study included responses from 91 participants with chronic pruritus (response rate: 74.6%). A survey including questionnaires regarding data on demographic characteristics, intensity of pruritus using the visual analog scale (VAS) and the 4-item itch questionnaire, and the degrees of insomnia and depression measured by the Insomnia Severity Index and Beck Depression Inventory, respectively. Results: Patients with symptoms of insomnia or depression had significantly more intense pruritus than patients without psychological symptoms (insomnia, VAS median [interquartile range]: 7.0 [5.0-8.25] vs. 5.0 [3.0-7.5]; depression, VAS median [interquartile range]: 7.5 [5.0-8.25] vs. 5.0 [3.0-7.0]). Multivariable analyses revealed that patients with moderate to severe pruritus were more likely to have depression than those with mild pruritus (odds ratio: 10.95; 95% confidence interval: 2.24-53.06). There were no differences in the severity of insomnia and depression among skin diseases. Limitations: This study had a cross-sectional design and limited generalizability. Conclusion: Chronic pruritus is significantly associated with insomnia and depression, regardless of the etiology.