Depression, anxiety, and delirium

Psychiatric disorders are common in the setting of malignant disease, occurring in almost 50% of patients. Many cancer patients cope well with their disease. For those who do not, untreated psychological and neuropsychiatric disorders can seriously compromise quality of life and treatment compliance. Although there is a wide variety of presentations, three behavioral syndromes that are often encountered in clinical practice will be discussed here: depression, anxiety, and delirium.

Depression

"Depression" exists on a continuum ranging from an emotion common in daily life (sadness) to a syndrome of severe physical and psychological symptoms consistent with a defined psychiatric disorder (major depressive disorder).

In cancer patients, identical symptoms may be caused or influenced by physical (eg, tumor site, pain), psychological (eg, stress, premorbid function, maturity), and social (eg, finances, interpersonal relationships) factors. Depression occurs more frequently in the setting of severe illness; several studies of cancer inpatients report a prevalence of 25%–42%.

SIGNS AND SYMPTOMS/DIAGNOSIS

Patients with depressive syndromes experience specific symptoms that vary in intensity and severity.

Psychological symptoms include dysphoria (sadness), anhedonia (pervasive loss of pleasure in activities), feelings of guilt or low self-esteem, and thoughts of death or suicide.

Somatic symptoms include sleep disturbance, change in appetite, loss of libido, fatigue, diminished concentration, and psychomotor agitation or withdrawal.

Focus of diagnostic evaluation Although the diagnosis of major depressive disorder requires that multiple symptoms (including dysphoria or anhedonia) must be present for at least 2 weeks, patients who do not meet these criteria may be in significant distress. The diagnosis of depression in medically ill patients is complicated by the fact that somatic symptoms of depression may also be caused by factors related to disease and treatment. For this reason, when evaluating the depressed cancer patient, special attention should be paid to psychological symptoms, which are less likely to be directly related to treatment.

ETIOLOGY

Psychological causes

Isolated symptoms Isolated depressive symptoms, if temporally related to an identifiable stressor, may be classified as adjustment disorders. In the setting of malignancy, obvious stressors include the initial diagnosis, treatment failure, or disease progression. Patients may also face potential psychosocial stressors, including changes in independence, body image, finances, and family function, as well as issues related to death and dying.

Persistent symptoms Persistent mood symptoms may indicate the presence of an evolving major depressive disorder. Major depressive disorder is common in the general population (point prevalence, ~6%) and is a recurrent disease. Patients with a history of mood disorder are at risk for relapse in the face of a cancer diagnosis.

Disease- and treatment-related causes

Presenting symptom of malignancy Depression may be a presenting symptom of some primary malignancies, including primary pancreatic and gastric carcinomas. Primary and metastatic brain tumors may cause frontal lobe syndromes or personality changes that mimic depression and other psychiatric disorders.