The Diagnostic and Statistical Manual of Psychiatric Disorders (DSM) provides a common language about mental disorders for researchers, clinicians, and payers. However, any mental disorder may have multiple underlying etiologies, which may limit the ability to develop treatments specifically targeted at these root causes. The Research Domain Criteria (RDoC) is a framework developed by the National Institute of Mental Health for classifying psychiatric disorders that shifts the focus of research from the current diagnostic system to simpler dimensions of mental functioning. RDoC addresses dimensional psychological constructs responding to threat, loss, or reward; cognitive capacity; social processes; and arousal and regulation. RDoC may one day provide a framework for developing better treatments that are targeted towards the underlying causes of mental illnesses.