Determination of psychosocial factors in cluster headache - construction and psychometric properties of the Cluster Headache Scales (CHS)

Background: Cluster headache (CH) is clinically associated with considerable psychosocial burden. However, instruments to assess and characterize psychosocial factors in cluster headache more specifically are lacking. This study aimed to develop a self-report questionnaire, which assesses the broadest possible spectrum of psychosocial factors in cluster headache, the Cluster Headache Scales (CHS).

Method: Items of the Cluster Headache Scales were constructed based on a literature review and semi-structured interviews with several experts (including persons with cluster headache). A cross-sectional online survey was conducted to determine the psychometric properties and the factor structure of the Cluster Headache Scales. Data was analyzed using exploratory factor analysis as well as exploratory structural equation modelling (ESEM).

Results: In total, n = 342 subjects with cluster headache (mean age 47.8, 63% male, 51% with episodic cluster headache) were included. Factor analysis yielded eight clearly interpretable factors: Medical care, medication side effects, fear of attacks, disability, (auto)aggression, coping, physical activity, and financial burden, which are assessed via 36 items. The internal consistencies of the subscales were acceptable to excellent and ranged between Cronbach's alpha = .76 and .93. The pattern of correlations with related instruments provides first evidence for convergent validity.

Conclusion: The CHS represents a reliable and valid self-report instrument for the assessment of psychosocial factors in persons with cluster headache, which appears useful for both clinical practice as well as research. Trial registration: The study was registered at the German Clinical Trials Register ( www.drks.de , ID-Number: DRKS00016502).

Keywords: Cluster headache; coping; disability; psychosocial factors; questionnaire.