The Headache-specific Locus of Control scale — a 33-item scale that evaluates healthcare professional, internal, and chance headache-specific loci of control — may represent a reliable and valid tool to assess headache-specific locus of control in individuals with migraine, according to study results published in Headache.
To evaluate the component structure, reliability, and construct validity of the Headache-specific Locus of Control scale, investigators conducted a cross-sectional study of 695 adult patients with migraine (average age, 40.8 years) enrolled in 5 different research studies.
Study participants were asked to complete self-report measures including the Headache-specific Locus of Control scale, the Migraine-specific Quality of Life Questionnaire, and the Migraine Disability Assessment. The average recorded monthly duration of migraine was 10.5 days, and the majority of participants met criteria for episodic migraine (n=557; 83.3%).
Five principal components of the Headache-specific Locus of Control scale of beliefs were identified using Horn’s Parallel Analysis, the Minimum Average Partial test, and the Principal Component Analysis: presence of internal (eigenvalue, 5.7), lack of internal (eigenvalue, 4.0), luck (eigenvalue, 2.9), doctor (eigenvalue, 2.0) and treatment (eigenvalue, 1.5).
The researchers reported that the 33 items of the Headache-specific Locus of Control were found to have adequate internal consistency for total (α =0.79) and subscale scores (α’s =0.69-0.88). Associations between higher overall migraine-specific quality of life impairments and lack of internal beliefs (r =–0.12; P =.004), doctor beliefs (r =–0.20; P <0001), and treatment beliefs (r =–0.12; P =.004) were established.
Limitations to this study include its small effect size and the inability to control for nonrandom variance within samples.
“This study provided evidence of construct validity as demonstrated by the observed associations between Headache-specific Locus of Control, migraine-specific quality of life, disability, and number of headache days. Additional examination of the associations between Headache-specific Locus of Control beliefs, emotions, psychiatric symptoms, and headache-related cognitions may elucidate the impact and role of control beliefs in people with migraine,” concluded the study authors.
Grinberg AS, Seng EK. Cross-sectional evaluation of the psychometric properties of the headache-specific locus of control scale in people with migraine [published online February 19, 2019]. Headache. doi: 10.1111/head.13485