Validation of Wearable Core Body Temperature-Based Circadian Rhythm Digital Biomarkers

Prior treatment

• Current or previous head trauma associated with loss of consciousness, degenerative neurological disease, or organic neurological disorder.
• History of clinically significant mood symptoms, defined as previous diagnosis or treatment for a mood disorder or evidence of a past or current major depressive, manic, or hypomanic episode on structured or screening assessment.
• Current use of sleep medications or psychotropic medications, including antidepressants, mood stabilizers, antipsychotics, or benzodiazepines.
• Current or previous head trauma associated with loss of consciousness, degenerative neurological disease, or organic neurological disorder.
• Current or previous head trauma associated with loss of consciousness, degenerative neurological disease, or organic neurological disorder.

Other illness

• History of moderate or severe intellectual disability.
• Fever (body temperature ≥37.5°C) or acute infection at the start of measurement.
• Skin disease at the sensor attachment site, history of allergy to medical adhesives, or another condition making sensor attachment inappropriate.
• History of moderate or severe intellectual disability.
• Fever (body temperature ≥37.5°C) or acute infection at the start of measurement.
• Skin disease at the sensor attachment site, history of allergy to medical adhesives, or another condition making sensor attachment inappropriate.
• Difficulty reading or understanding Korean.
  • Study 2 - Psychiatric inpatient group
• History of moderate or severe intellectual disability.
• Fever (body temperature ≥37.5°C) or acute infection at the start of measurement.
• Skin disease or history of allergy to medical adhesives that makes sensor attachment inappropriate.

Other

• Shift work, including night work, within the preceding 3 months.
• Travel across three or more time zones within the preceding 2 weeks.
• Pregnancy or breastfeeding.
• Difficulty reading or understanding Korean.
• Considered unsuitable for study participation by the principal investigator.
  • Study 1 - Healthy control group
• Shift work, including night work, within the preceding 3 months.
• Travel across three or more time zones within the preceding 2 weeks.
• Pregnancy or breastfeeding.
• An acute safety concern, including risk of harm to self or others, that makes wearable monitoring or study assessment inappropriate.
• Lack of capacity to provide informed consent or difficulty providing voluntary informed consent.
• Pregnancy or breastfeeding.
• Difficulty reading or understanding Korean.

• Adults aged 19-75 years.
• Meets DSM-5 criteria for major depressive disorder, bipolar I disorder, or bipolar II disorder based on a structured diagnostic interview and clinical assessment, with a history of psychiatric consultation for related symptoms.
• Agrees to wear both the core body temperature sensor and wrist-worn wearable device for approximately 7 days.
  • Study 1 - Healthy control group
• Adults aged 19-75 years.
• Has no history of psychiatric diagnosis or treatment and is not identified as having a major mood disorder on structured diagnostic assessment.
• Agrees to wear both the core body temperature sensor and wrist-worn wearable device for approximately 7 days.
  • Study 2 - Psychiatric inpatient group
• Adults aged 19-75 years.
• Admitted to the psychiatric inpatient unit of Korea University Anam Hospital for psychiatric treatment; a confirmed final diagnosis is not required at enrollment.
• Agrees to continuously wear the core body temperature sensor and Fitbit during the inpatient study period.