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, psychological counseling or both.
Although depression may occur only one time during your life, usually people have multiple episodes of depression. During these episodes, symptoms occur most of the day, nearly every day and may include:
- Feelings of sadness, tearfulness, emptiness or hopelessness
- Angry outbursts, irritability or frustration, even over small matters
- Loss of interest or pleasure in most or all normal activities, such as sex, hobbies or sports
- Sleep disturbances, including insomnia or sleeping too much
- Tiredness and lack of energy, so even small tasks take extra effort
- Changes in appetite — often reduced appetite and weight loss, but increased cravings for food and weight gain in some people
- Anxiety, agitation or restlessness
- Slowed thinking, speaking or body movements
- Feelings of worthlessness or guilt, fixating on past failures or blaming yourself for things that aren’t your responsibility
- Trouble thinking, concentrating, making decisions and remembering things
- Frequent or recurrent thoughts of death, suicidal thoughts, suicide attempts or suicide
- Unexplained physical problems, such as back pain or headaches
For many people with depression, symptoms usually are severe enough to cause noticeable problems in day-to-day activities, such as work, school, social activities or relationships with others. Other people may feel generally miserable or unhappy without really knowing why.
It’s not known exactly what causes depression. As with many mental disorders, a variety of factors may be involved, such as:
- Biological differences. People with depression appear to have physical changes in their brains. The significance of these changes is still uncertain, but may eventually help pinpoint causes.
- Brain chemistry. Neurotransmitters are naturally occurring brain chemicals that likely play a role in depression. Recent research indicates that changes in the function and effect of these neurotransmitters and how they interact with neurocircuits involved in maintaining mood stability may play a significant role in depression and its treatment.
- Hormones. Changes in the body’s balance of hormones may be involved in causing or triggering depression. Hormone changes can result with pregnancy and during the weeks or months after delivery (postpartum) and from thyroid problems, menopause or a number of other conditions.
- Inherited traits. Depression is more common in people whose blood relatives also have this condition. Researchers are trying to find genes that may be involved in causing depression.
To learn more about depression, visit The Mayo Clinic.