Table 2 Validated questionnaires used for additional outcomes with comments regarding relevance for present study and references to the literature list

Short Form-36 (SF-36)

Most used general QoL questionnaire

Enables quality of life comparison with non-headache patients from the general population ., normal material for Norwegian population exists

[89–91]

Migraine Disability Assessment (MIDAS) Headache Impact Test – 6 (HIT-6)

Most used headache specific QoL instruments, recommended for RCTs of headache treatment

Enables comparison between various headache categories

[92, 93]

Severity of Dependence Scale (SDS)

Validated for detection of MOH in previous studies

Simple identification of MOH patients, comparison against scores for other addictive drugs

[58, 94]

Mini International Neuropsychiatric Interview (MINI)

Validated structured interview for DSM-IV based diagnosis of substance dependency

Gold standard for dependency for validation of SDS

[58, 94]

Eysenck Personality Questionnaire (EPQ)

Widely used personality scale both in relation to drug dependency and in more general

Assessment of personality as a factor which may affect outcomes after a behavioural intervention, Norwegian population standards exist

[95–97]

Hopkins Symptom Checklist-25 (HSCL-25)

Well validated scale for symptoms of psychological distress

Supplement to Eysenck for assessing degree of distress which may affect outcomes of behavioural intervention, Norwegian population standards exist

[98–100]

Hospitality and Anxiety Depression Scale (HADs)

Most used scale in clinical materials for scoring depressive and anxiety symptoms

Assessment of depression and anxiety as comorbidities of chronic headache which may affect outcomes of intervention, Norwegian population standards exist

[101, 102]