Many of us experience a sad or down mood now and then. This is different than clinical depression, which symptoms can include: hopelessness, changes in appetite, sleep problems, slowed thinking or memory problems, poor energy levels, and sometimes even thoughts of death or self-harming behaviors. These symptoms can significantly impair your lifestyle and even become dangerous. Like anything else, depression comes in mild, moderate, and severe varieties. In addition, chronic use of chemicals like alcohol and/or drugs can lead to depression.

Another form of a mood disorder is called bipolar disorder which also can be associated with chronic substance abuse. With bipolar disorder, the person can have the down moods of depression and "high" moods called mania. This high mood can include talking and thinking very rapidly, grandiosity, significant irritability, little need for sleep, and even dangerous risky behaviors like driving fast or hurting others.

Both clinical depression and bipolar symptoms need careful evaluation by a trained professional like a psychiatrist, psychologist or clinical social worker. Treatment options vary depending of the severity of the symptoms and can include both medications and behavior therapy.