This case-control study will examine whether adolescents aged 12-18 years with a diagnosis of primary headache are more likely to experience elevated social anxiety compared to matched healthy controls. Social anxiety will be assessed using the SAS-A, and the study will also explore whether environmental and sociodemographic factors such as tobacco smoke exposure, BMI, and parental education influence this relationship.

The study will include adolescents aged 12-18 years who have been diagnosed with primary headachebased on the International Classification of Headache Disorders, 3rd edition (ICHD-3). The main exposure ofinterest will be the presence and severity of social anxiety, which will be measured using the Social AnxietyScale for Adolescents (SAS-A), a validated self-report questionnaire. The SAS-A takes approximately 10minutes to complete. Additional variables that will be collected will include sociodemographiccharacteristics, BMI, parental education levels, income status, parental smoking habits, and theadolescent's exposure to secondhand and thirdhand tobacco smoke. All assessments, includingquestionnaires and physical measurements (height and weight), are expected to be completed inapproximately 20 minutes per participant. The total observation duration for each participant will be about30 minutes.

Inclusion Criteria:

• Adolescents aged 12-18 years
• Case group: Participants who will be diagnosed with primary headache according to InternationalClassification of Headache Disorders, 3rd edition (ICHD-3) criteria, confirmed by a pediatric neurologist
• Control group: Participants who will have no history of recurrent headache or chronic physical/psychiatricillness

Exclusion Criteria:

• History of neurological disease other than primary headache
• Any previously diagnosed psychiatric disorders
• Regular use of psychotropic medications
• Cognitive or developmental disabilities that would interfere with assessments

Case group: Participants who will be diagnosed with primary headache according to InternationalClassification of Headache Disorders, 3rd edition (ICHD-3) criteria, confirmed by a pediatric neurologist Control group: Participants who will have no history of recurrent headache or chronic physical/psychiatricillness

All de-identified individual participant data

Requires review on a case-by-case basis by the trial custodian, sponsor or data sharing committee

• Requires a scientifically sound proposal or protocol

• Requires approval by an ethics committee

• Requires a data sharing agreement between data requester and trial custodian or sponsor