Chinese Longitudinal and Systematic Study of Bioplar Disorder

This study is looking at the biology behind depression and bipolar disorder — specifically how the immune system and brain may be connected in people experiencing these conditions. You may be eligible if: - You are between 16 and 65 years old - Both of your biological parents are of Han Chinese heritage - You have been diagnosed with a depressive episode related to major depression or bipolar disorder - You have not taken any immune-modifying medicines in the past month - You have not had a respiratory, urinary, or digestive infection in the past month You may NOT be eligible if: - You have been diagnosed with schizophrenia, a developmental disorder, dementia, or significant memory or thinking problems - You have a mental health condition caused by substance use (like alcohol or drugs) - You have a serious physical illness such as uncontrolled diabetes, thyroid disease, heart disease, liver or kidney problems, or an autoimmune disease - You have taken antidepressants, antipsychotics, or mood stabilizers in the past month - You have had electroconvulsive therapy (ECT) before - You are currently having serious thoughts of suicide or are in a mental health crisis - You are pregnant, breastfeeding, or planning to become pregnant - You have reasons that make MRI scans unsafe for you Talk to your doctor to see if this trial is right for you.