Also known as unipolar disorder, major depression is a syndrome of persistently sad, dysphoric mood accompanied by disturbances in sleep and appetite, lethargy, and an inability to experience pleasure (anhedonia). Major depression occurs in 3% to 5% of adults, affecting all racial, ethnic, and socioeconomic groups. It affects both sexes but is more common in wo
About half of all depressed patients experience a single episode and recover completely; the rest have at least one recurrence. Major depression can profoundly alter social, family, and occupational functioning.
However, suicide is the most serious complication of major depression, resulting when the patient’s feelings of worthlessness, guilt, and hopelessness are so overwhelming that he no longer considers life worth living. Nearly twice as many women as men attempt suicide, but men are far more likely to succeed.
The multiple causes of depression aren’t completely understood. Current research suggests possible genetic, familial, biochemical, physical, psychological, and social causes.
Such causes may include feelings of helplessness and vulnerability, anger, hopelessness and pessimism, and low self-esteem; they may be related to abnormal character and behavior patterns and troubled personal relationships.
In many patients, the history identifies a specific personal loss or severe stressor that probably interacts with the person’s predisposition to provoke major depression.
Depression may be secondary to a specific medical condition—for example, metabolic disturbances, such as hypoxia and hypercalcemia; endocrine disorders, such as diabetes and Cushing’s disease; neurologic diseases, such as Parkinson’s and Alzheimer’s disease; and cancer, especially of the pancreas.
Other medical conditions that may underlie depression include viral and bacterial infections, such as influenza and pneumonia; cardiovascular disorders such as heart failure; pulmonary disorders such as chronic obstructive pulmonary disease; musculoskeletal disorders such as degenerative