Most mental disorders such as anxiety or depression can have multiple underlying causes. The National Institute of Mental Health’s Research Domain Criteria (RDoC) is a new method of classifying normal and abnormal mental processes underlying psychological disorders. RDoC is not currently a tool that can be used for clinical care or replace the DSM (Diagnostic and Statistical Manual of Mental Disorders). However, RDoC may one day provide an approach for developing better treatments that are targeted towards the underlying causes of mental illnesses.