NIMH NIH clinical researchers test new ways to prevent, detect, or treat mental illnesses and psychiatric disorders. Learn more about how to participate in outpatient and inpatient studies at the NIH Clinical Center for adults and children with depression, bipolar disorder, anxiety, schizophrenia, postpartum depression, perimenopausal depression, premenstrual syndrome, suicidality, Trisomy X, autism spectrum disorders, ADHD, dysruptive mood dysregulation disorder, and others.