Depression may also be tied to disturbances in the biochemicals that regulate mood and activity. These biochemicals, called neurotransmitters, are substances that carry impulses or messages between nerve cells in the brain. An imbalance in the amount or activity of neurotransmitters can cause major disruptions in thought, emotion and behavior. Some people develop depression as a reaction to other biological factors such as chronic pain, medications, hypothyroidism or other medical illnesses. Because depression appears to be linked to certain biological factors, people can inherit a predisposition to develop depression.
Doctors know more about depression than perhaps any other emotional illness.
A complete evaluation with a qualified professional is the first step in seeking treatment. Only a licensed physician or psychologist can diagnose a person with a psychiatric disorder During the diagnostic evaluation, the physician or psychologist will determine if any other factors are contributing to or even causing the depressive symptoms. Various psychotherapies or 'talk therapies' commonly used in the treatment of depression focus on the causes and effects of the illness. Interpersonal therapy helps people deal with problems in personal relationships. Cognitive therapy helps patients change negative thoughts or perceptions, such as high achievers who are convinced they are failures.