A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be willed or wished away. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people who suffer from depression. The symptoms of depression may vary from person to person, and also depend on the severity of the depression.
Depression causes changes in thinking, feeling, behavior, and physical well-being.
Changes in Thinking - You may experience problems with concentration and decision making. Some people report difficulty with short term memory, forgetting things all the time. Negative thoughts and thinking are characteristic of depression. Some people have self-destructive thoughts during a more serious depression. Changes in Feelings - You may feel sad for no reason at all.