The National Institute of Mental Health (NIMH) is committed to reducing the burden of mental illness through research on mind, brain, and behavior. This report presents the latest information on what is known about depression. The symptoms and types of depression are considered. Research on the treatments of depression is described, including the medications recommended, psychotherapy alternatives, electroconvulsive treatment, genetic links, stress factors, hormonal abnormalities, and co-occurrence with other disorders. Discussion is also provided relating to the finding that women are affected by depression and the factors that contribute to this phenomenon twice as often as men. Children and adolescents are also susceptible to depression and several causal factors are reviewed. Areas such as brain imaging, thought process, and biological markers are just a few of the topics considered for future areas of NIMH depression research. (JDM)