Background     Depression is a significant symptom for approximately 1 in 4 palliative care patients (see Fast Fact #21).  Depressive symptoms correlate with reductions in quality of life, adherence to medical therapies, and symptom control among patients with serious illness. Up to 80% of the psychological symptoms that occur in patients with advanced illness go unrecognized and untreated.  One reason for this is the difficulty in diagnosing depression in patients with serious illness (see Fast Fact #7).  In the primary care literature, several screening instruments such as Patient Health Questionnaire (PHQ-9) are used to identify depression. However, the symptoms associated with depression in primary care (weight loss, sexual dysfunction, loss of energy, fatigue, insomnia) also occur in patients without depression who have a life-threatening disease. Furthermore, the PHQ-9 entails 9-questions which may make it too long to reliably serve as a screening tool for all patients with a serious illness. Thus, there has been interest in developing briefer scales that can be more reliably and routinely utilized. This Fast Fact reviews that literature on brief depression screening tools among palliative care patients.

Single- (or two-) question screening: A study of palliative care inpatients found that a single question, “Are you feeling down, depressed or hopeless most of the time over the last 2 weeks?” correctly identified patients with 100 percent sensitivity and specificity and a positive predictive value (PPV) of 1 (Chochinov 1997).  Adding a second question about anhedonia (the absence of pleasure from the performance of acts that would normally be pleasurable), “Have you found that little brings you pleasure or joy over the last two weeks?”, reduced the specificity and PPV.  Unfortunately, follow-up studies using a single question regarding mood in other palliative care populations have shown a lower sensitivity (55-80%) specificity (75-85%), and PPV (0.57). To improve diagnostic accuracy, Chochinov’s 2-question screening tool was modified into the PHQ-2 (Kroenke 2003).  Patients who score 1 or greater on the PHQ-2 have at least a 36.9% probability of a depressive disorder. Experts recommend that these patients should be subsequently interviewed with the PHQ-9 tool to improve depression diagnostic accuracy.

A four-item algorithm asks questions about energy level, anhedonism, depressed mood, and psychomotor retardation/agitation.  In a study of hospice patients in Australia this tool had a sensitivity between 62 and 72%, specificity of 75 to 89% and a PPV of between 68 and 89% (Robinson 2005).

The four question Brief Case Find for Depression asks questions about sleep, depressed mood, life satisfaction, and ability to overcome difficulties. In a study of oncology and palliative care patients this tool had fair agreement with longer depression screening instruments (Jefford 2004).

The Distress Thermometer measures the subjective perception of emotional distress on a 0-10 visual analogue scale.  Though it is brief and therefore well-suited for broad use across a large patient population, it only appears to be helpful at ruling out depressive symptoms at a cutoff of < 7 and scores 7 or greater do not seem to confirm depression (Donovan 2014).

Other studies have examined 10-20 question depression instruments. The Edinburgh Postnatal Depression Scale (Lloyd-Williams 2000), a self-assessment scale consisting of ten items each rated on a 4-point scale, had a sensitivity of 70% and specificity of 80% in patients with metastatic cancer receiving palliative care.  The Hospital Anxiety and Depression Scale (Lloyd-Williams 2003) is a 14-item scale with separate sub-scales for anxiety and depression.  In patients with metastatic cancer, summing the two subscales gave a sensitivity of 77%, specificity was 89% and a PPV of 0.48.  Follow-up studies however reported lower sensitivity and specificity.

Summary and Recommendations

• Clinicians should have a high clinical suspicion for depression—especially in patients who exhibit feelings of hopelessness, worthlessness, guilt, anhedonia, sustained periods of feeling sad, and/or those with suicidal ideation and/or suicidal plans.
• The literature does not suggest that any of the above scales are clearly superior for helping to diagnose depression in a population of palliative care patients. The PHQ-2 may be a worthwhile screening tool to employ routinely for all palliative care patients. Its diagnostic accuracy may be improved by coupling it with the PHQ-9 for any patient that scores a 1 or greater on the PHQ-2.
• Clinicians should be familiar with sensitivity/specificity/PPV data for any scale utilized in practice.
• Psychiatric consultation is indicated in cases of diagnostic uncertainty and/or when patients present with profound depression and/or are overtly suicidal.

Definitions (Further resources available at:  http://www.musc.edu/dc/icrebm/diagnostictests.html.)

• Sensitivity: The fraction of those with the disease correctly identified as positive by the test.
• Specificity: The fraction of those without the disease correctly identified as negative by the test.
• PPV: The fraction of people with positive tests who actually have the condition.

References

1. Chochinov HM, Wilson K, Enns G, et al. “Are you depressed?” Screening for depression in the terminally ill. Am J Psychiatry. 1997; 154(5):674-676.
2. Lloyd-Williams M, Spiller J, Ward J. Which depression screening tools should be used in palliative care?  Pall Med. 2003; 17:40-43.
3. Lloyd-Williams M, Friedman T, Rudd N. Criterion validation of the Edinburgh Postnatal depression scale as a screening tool for depression in patients with advanced metastatic cancer. J Pain Symp Man. 2000; 20:259-65.
4. Jefford M, Mileshkin L, Richard K, Thomson J et al. Rapid screening for depression- validation of the Brief Case-Finding for Depression (BCD) in medical oncology and palliative care patients.  Br J Cancer. 2004; 91:900-6.
5. Robinson JA, Crawford GB. Identifying palliative care patients with symptoms of depression: an algorithm. Pall Med. 2005; 19:278-87.
6. Kroenke K, Spitzer RL, Williams JB. The Patient Health Questionnaire-2: validity of a two-item depression screener. Med Care 2003; 41:1284.
7. Taylor L, Lovell N, et al. Diagnosis of depression in patients receiving specialist community palliative care: does using a single screening question identify depression otherwise diagnosed by clinical interview? Journal of Palliative Medicine 2013; 16(9):1140-1142.
8. Hinz A, Mehnert A, et al. Assessment of depression severity with the PHQ-9 in cancer patients and in the general population.  BMC Psychiatry 2016; 16(22): https://doi.org/10.1186/s12888-016-0728-6
9. Donovan KA, Grassi L, McGinty HL, et al. Validation of the distress thermometer worldwide: state of the science. Psychooncology. 2014;23:241–250.

Version History:  This Fast Fact was originally edited by David E Weissman MD and published in December 2005.  Version re-copy-edited in April 2009; revised again July 2015; and again in January 2024 by Sean Marks MD.