Depressive disorders are the most common psychiatric problem seen in medical–surgical patients. The point prevalence rate for depression is 10%–36% for general medical inpatients. The presence of depression has a significant effect on the patient's morbidity and mortality. Patients with depression following a myocardial infarction are 3.5 times more likely to die in the next 6 months than patients without depression.
The causes of depression in medically ill patients are multiple, including dealing with loss, helplessness, pain, lowered self-esteem, and financial and marital strain after illness. In many cases, depressive symptoms may result from the underlying physical illness or medications used in treatment.
Most depressive reactions in medical–surgical patients are relatively short, resolve after surgery, and do not cause major disturbances in social, occupational, interpersonal, physical, or psychological functioning. If depressive symptoms persist, they become major depression.
Major depression is characterized by a markedly depressed mood or loss of interest or pleasure in life (see Table 39.1). This depressed mood lasts longer than 2 weeks and causes significant disruptions in patient's occupational, social, and interpersonal functioning. Physical symptoms of depression can include sleep disturbances, appetite disturbance or weight change, fatigue, and physical feelings of being slowed down. Emotional symptoms can include disinterest, apathy, low self-esteem, hopelessness, helplessness, and guilt. Some patients will have suicidal thoughts or active plans for suicide. When severe, depression in the medically ill may give rise to psychotic symptoms, including paranoia, hallucinations, delusions (including somatic delusions of insect infestation), and obsessive–compulsive behavior.