According to the American Psychiatric Association (APA), depression (major depressive disorder) is a common and serious medical illness that negatively affects how a person feels, thinks, and acts. Depression causes feelings of sadness and/or a loss of interest in activities once enjoyed. It can lead to a variety of emotional and physical problems and can decrease a person’s ability to function at work and at home. Depression is often comorbid with substance use disorders.
Depression symptoms can vary from mild to severe and can include:
- Feeling sad or having a depressed mood
- Loss of interest or pleasure in activities once enjoyed
- Changes in appetite — weight loss or gain unrelated to dieting
- Trouble sleeping or sleeping too much
- Loss of energy or increased fatigue
- Increase in purposeless physical activity (e.g., hand-wringing or pacing) or slowed movements and speech (actions observable by others)
- Feeling worthless or guilty
- Difficulty thinking, concentrating or making decisions
- Thoughts of death or suicide
Symptoms must last at least two weeks for a diagnosis of depression.
For more information on the types of depressive disorders, click here.