Cross‐Sectional Evaluation of the Psychometric Properties of the Headache‐Specific Locus of Control Scale in People With Migraine

Abstract

Objective This study aims to investigate the psychometric properties (component structure, reliability, and construct validity) of the Headache‐Specific Locus of Control scale in several clinical migraine populations. Background Headache‐specific locus of control beliefs may impact a person’s behavioral decisions that affect the likelihood of migraine attack onset, emotional responses to migraine attacks, coping strategies used, and treatment adherence. The 33‐item Headache‐Specific Locus of Control scale is the most widely used measure of locus of control specific to headache yet psychometric evaluations remain limited. Methods Six hundred and ninety‐five adults with a diagnosis of migraine from 5 different research studies completed cross‐sectional self‐report measures including the Headache‐Specific Locus of Control scale and measures of quality of life and disability (Migraine‐Specific Quality of Life Questionnaire and Migraine Disability Assessment). Results Five Headache‐Specific Locus of Control components emerged from Horn’s Parallel Analysis, Minimum Average Partial test, and Principal Component Analysis (eigenvalues: Presence of Internal = 5.7, Lack of Internal = 4.0, Luck = 2.9, Doctor = 2.0, and Treatment = 1.5). The 33 Headache‐Specific Locus of Control items demonstrated adequate internal consistency for total (α = 0.79) and subscale scores (α’s = 0.69 to 0.88). This study found preliminary evidence of convergent validity. For example, Lack of Internal (r = −0.12, P = 0.004), Doctor (r = −0.20, P < .001), and Treatment (r = −0.12, P = .004) beliefs were associated with higher overall migraine‐specific quality of life impairments. Conclusions The Headache‐Specific Locus of Control scale is a reliable and valid measure of headache‐specific locus of control. Findings suggest that headache‐specific locus of control is more multidimensional than previous conceptualizations and contribute to our understanding of control beliefs as a potential mechanism for migraine treatment.