The Eurolight questionnaire differentiates EH (headache on < 15 days/month) from CH (headache on ≥ 15 days/month) and is validated for diagnosing migraine, probable migraine, TTH, probable TTH, and pMOH according to the International Classification of Headache Disorders, 2nd edition (ICHD-2) [17] and for assessing the impact of headache disorders [16].
The Eurolight questionnaire differentiates EH, i.e. headache on <15 days/month, and CH, i.e. headache on ≥15 days/month, and it is validated for diagnosing migraine, probable migraine, tension -type headache (TTH), probable tension-type headache (pTTH) and probable medication overuse headache (pMOH) according to ICHD-2 [16, 16].
The PHQ-9 has been validated for both diagnosing depression and measuring severity [ 34- 36].
The HDR data have been validated for psychiatric diagnoses and are considered good [ 24- 26].
Though we relied on claims data to assign diagnoses to admissions, administrative codes have been validated for cardiovascular and pulmonary diagnoses.
This register, launched in 1964, has complete coverage of inpatient care since 1982 and has been validated for a number of diagnoses [ 10].
These data contain electronic information on consultations, diagnoses, and prescriptions delivered in primary care in the United Kingdom, and have been validated for a wide variety of diagnoses (23).
THIN is a nationally representative database of computerised primary care records from across the UK that has been validated for pharmacoepidemiology studies, and contains diagnoses, events, symptoms, and drug prescriptions.
Registry data samples have been validated for gestational age, birth defects, and infant neoplasm diagnoses [ 26].
In some studies, diagnoses are based only on screening instruments; in others, the diagnostic interviews used have not been validated for both SUDs and mental disorders.
