Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest. Also called major depressive disorder or clinical depression, it affects how you feel, think and behave and can lead to a variety of emotional and physical problems. You may have trouble doing normal day-to-day activities, and sometimes you may feel as if life isn’t worth living.

More than just a bout of the blues, depression isn’t a weakness and you can’t simply “snap out” of it. Depression may require long-term treatment. But don’t get discouraged. Most people with depression feel better with medication, psychotherapy or both.

Anxiety is your body’s natural response to stress. It’s a feeling of fear or apprehension about what’s to come. For example, going to a job interview or giving a speech on the first day of school may cause some people to feel fearful and nervous.

But if your feelings of anxiety are extreme, last for at least 6 months, and are interfering with your life, you may have an anxiety disorder.