Depression affects millions of men, women, and children in the U.S. WebMD's Depression Guide has the information you need to understand all about depression -- the causes, symptoms, diagnosis, treatment, and complications such as pain perception, sexual problems, and sleep disturbances. Depression carries a high risk of suicide. Anybody who expresses suicidal thoughts or intentions should be taken very, very seriously. Do not hesitate to call your local suicide hotline immediately. Call 1-800-SUICIDE (1-800-784-2433) or 1-800-273-TALK (1-800-273-8255).