In medical terms, morbidity refers to a condition or state of being diseased. Morbid depression refers to an evident, existing depressive disorder.
According to the National Institute of Mental Health (NIMH), the most common types of depressive disorder are major depressive disorder and dysthymic disorder. Other types of depressive disorder include psychotic depression, postpartum depression, and seasonal affective disorder.
According to the NIMH, the cause of depression is unclear, though a combination of factors such as genetics, biochemistry, and environment may contribute to depression.
Symptoms of depression may include a sad or anxious mood, hopelessness, lack of interest in pleasurable activities, fatigue, difficulty concentrating, changes in eating and sleeping habits, and suicide ideation or attempts. Those with depression may also experience chronic pain that is resistant to treatment.
When illnesses co-exist they are considered to be co-morbid. According to the NIMH, depression can be accompanied by co-morbid anxiety disorders including post-traumatic stress disorder, panic disorder, obsessive compulsive disorder and social phobia.
Antidepressant medication, such as Prozac and Zoloft, may treat depressive symptoms. Psychotherapy, such as cognitive-behavioral therapy and interpersonal therapy, may also help treat depression.
Stimulants, anti-anxiety drugs, and other medications may be prescribed with antidepressants in cases of co-morbid mental or physical disorders.