We hope to learn more about the biology of psychiatric illness with the hope of improving the diagnosis and treatment of such psychiatric conditions as major depression.

From the blood sample you donate, the researchers will obtain DNA. This DNA will be used to search for DNA markers related to the underlying biology of psychiatric illness and how this might explain the symptoms of these disorders. Research using DNA is an important way to try to understand human disease and/or the role genes play in disease. In effect, part of your blood sample will be used to attempt to understand how genetic factors contribute to the symptoms of such psychiatric conditions as major depression.

Inclusion Criteria:

1. You are currently experiencing symptoms that are consistent with an episode of major depression without symptoms of psychosis (such as hallucinations, delusions or disorder of thought process), or
2. You are currently experiencing symptoms that are consistent with an episode of major depression with symptoms of psychosis (such as hallucinations, delusions or disorder of thought process), or
3. You have been diagnosed with either schizophrenia or schizoaffective disorder, or
4. You are a volunteer without a history of psychiatric illness (a healthy control subject).