Assessment and Diagnosis
Evaluation of depression in people with cancer should include careful assessment of symptoms, treatment effects, laboratory data results, physical status, and mental status. Although the etiology of depression is largely unknown, many risk factors for depression are known (see list below). Limited data suggest that depressive symptomatology in cancer patients undergoing cytokine therapy with interferon-alfa and interleukin-2 may be mediated by changes in availability of neurotransmitter precursors. For patients with head and neck cancer treated with curative intent, eight pretreatment variables (tumor stage, sex, depressive symptoms, openness to discuss cancer in the family, perceived available support, received emotional support, tumor-related symptoms, and size of the informal social network) can be used to predict which patients are likely to become depressed up to 3 years after treatment.[4,5] A prospective study of terminally ill Japanese patients who were assessed for psychiatric illness by structured clinical interview at the time of registration (baseline) and again at admission to a palliative care unit (follow-up) found that 5 (42%) of the 12 patients diagnosed with adjustment disorder at baseline progressed to major depression at follow-up. Only the Hospital Anxiety and Depression Scale was significantly predictive of psychiatric diagnoses at follow-up. Heightened awareness of this facilitates early diagnosis and the use of appropriate interventions. In the medically ill, early manifestations of delirium may be mistaken for anxiety or depression. These disorders should be considered among the differential diagnoses in individuals who present with depressive symptoms.
Risk Factors for Depression in People With Cancer
- Cancer-related risk factors:
- Depression at time of cancer diagnosis.[8,9]
- Poorly controlled pain.
- Advanced stage of cancer.
- Increased physical impairment or discomfort.
- Pancreatic cancer.
- Being unmarried and having head and neck cancer.
- Treatment with certain chemotherapeutic agents:
- Noncancer-related risk factors:
- History of depression:
- Two or more episodes in a lifetime.
- First episode early or late in life.
- Lack of family support.
- Additional concurrent life stressors.
- Family history of depression or suicide.
- Previous suicide attempts.
- History of alcoholism or drug abuse.
- Concurrent illnesses that produce depressive symptoms (e.g., stroke or myocardial infarction).
- Past treatment for psychological problems.
Screening and Assessment for Depression
Because of the common underrecognition and undertreatment of depression in people with cancer, screening tools can be used to prompt further assessment. Among the physically ill, in general, instruments used to measure depression have not been shown to be more clinically useful than an interview and a thorough examination of mental status. Simply asking the patient whether he or she is depressed may improve the identification of depression.
The following screening tools are commonly used:
- A single-item interview. In persons with advanced cancer, a single-item interview question has been found to have acceptable psychometric properties and can be useful. One example is to ask "Are you depressed?" Another example is to say, "Please grade your mood during the past week by assigning it a score from 0 to 100, with a score of 100 representing your usual relaxed mood." A score of 60 is considered a passing grade.
- The Hospital Anxiety and Depression Scale. The Hospital Anxiety and Depression Scale may have limited utility in certain patient populations such as early-stage breast cancer  and palliative care.[22,23]
- The Psychological Distress Inventory.
- The Edinburgh Depression Scale.
- The Brief Symptom Inventory.
- The Zung Self-Rating Depression Scale.
- The Distress Thermometer.