Clinical depression refers to a long-term mental state characterized by feelings of sadness, inadequacy and in severe cases, suicidal thoughts. Clinical depression is diagnosed when an individual experiences a depressed mood for more than two weeks and the depression begins to interfere with daily living.
Depression is caused by an imbalance in neurotransmitters in the brain and is most often treated with one or a combination of antidepressants and psychotherapy.
Chronic pain and depression are believed to be correlated. Chronic pain and its effects on one's quality of life can lead to depression, and conversely depression and its physiological effects can lead to chronic pain.
If an individual has both chronic pain and depression, it is usually recommended that both conditions be treated simultaneously.