Most people feel sad or irritable from time to time. They may say they're in a bad mood. A mood disorder is different. It affects a person's everyday emotional state. Nearly one in ten people aged 18 and older have mood disorders. These include depression and bipolar disorder (also called manic depression).

Mood disorders can increase a person's risk for heart disease, diabetes, and other diseases. Treatments include medication, psychotherapy, or a combination of both. With treatment, most people with mood disorders can lead productive lives.