Depression can cause significant chemical changes to the brain that may make it difficult for many people to overcome it without some time of professional help or treatment. People who are depressed often find it difficult to concentrate. Sometimes they feel like they are on an emotional roller-coaster, sometimes they have trouble getting sad or anxious thoughts out of their minds, and sometimes they just have no energy at all. Depressed people sometimes have significant weight changes, either up or down. They may have difficulty sleeping, especially in the early morning.
Some depressed people sleep more than usual.
Sexual interest may decrease. Untreated, depression can last for months or even years. It may resolve by itself, but it often reoccurs. With treatment, those who suffer from depression often report significant relief within 4-6 weeks. Clinical depression is readily treatable with counseling and medication.