Inclusion Criteria:

• High-risk offsprings of parents with BD: Aged 6-18 yrs, both male and female. Offsprings and parents can sign the writtened informed consent form. At least one of parents was diagnosed with bipolar disorder by two or more senior psychiatric doctor.
• Atypical depression: Aged 6-18 yrs, both male and female. Patients and parents can sign the writtened informed consent form. Patients was diagnosed with atypical depression by two or more senior psychiatric doctor according to DSM-5. The disease phase and treatment regime are unrestricted.
• Health control: health individuals with age and gender matched with high-risk offsprings, no psychiatric family history.

Exclusion Criteria:

• High-risk offsprings of parents with BD: HCL-32 total score > 12. Individuals was diagnosed with BD or have symptoms of Axis I psychiatric disorder screened by K-SADS-PL . Individuals with severe physical disease, including kidney diseases, liver diseases or nervous system diseases etc.
• Atypical depression: HCL-32 total score > 12. Individuals was diagnosed with BD or have symptoms of Axis I psychiatric disorder screened by K-SADS-PL . Individuals with severe physical disease, including kidney diseases, liver diseases or nervous system diseases etc. Patients cormobid substance abuse or treated with MECT in recent half a year.
• Health control: Individuals with psychiatric family history, severe physical disease, including kidney diseases, liver diseases or nervous system diseases etc.