2.5. Sleep-Related Questionnaire
depression, major depression
A self-report questionnaire was used to evaluate circadian preference, mood, and sleep-related parameters. Mental health metrics were assessed using the Patient Health Questionnaire (PHQ-9). The PHQ-9 assesses depression severity over the past two weeks. It is comprised of 9 items, and the total score is 27 points. A PHQ-9 score ≥ 10 is considered as major depression [