Depression screening tests can be valuable, with the most widely one used being the Patient Health Questionnaire-9 (PHQ-9). It is important to understand, however, that the results obtained from the use of any depression screening or rating scales do not diagnose depression and may be imperfect in any population, especially in elderly patients.
The U.S. Preventive Services Task Force (USPSTF) recommends screening for depression in the general adult population, including older adults and pregnant and postpartum women.  It is important to understand that the results obtained from the use of any depression rating scales are imperfect in any population, especially the geriatric population.
The simplest screening test is a single question: Are you depressed? A pooled analysis found that single-question screening had a specificity of 97% but an overall sensitivity of 32% and, thus, would identify only 3 of every 10 patients with depression in primary care. 
The following 2-question test addresses depressed mood and anhedonia:
During the past month, have you been bothered by feeling down, depressed, or hopeless?
During the past month, have you been bothered by little interest or pleasure in doing things?
In a cross-sectional study, these 2 screening questions showed a sensitivity of 97% and a specificity of 67%. 
Longer self-report screening instruments for depression include the following:
PHQ-9 – The 9-item depression scale of the Patient Health Questionnaire; each item is scored 0 to 3, providing a 0 to 27 severity score
Beck Depression Inventory (BDI) or Beck Depression Inventory-II (BDI-II) – 21-question symptom-rating scales
BDI for primary care – A 7-question scale adapted from the BDI
Zung Self-Rating Depression Scale – A 20-item survey
Center for Epidemiologic Studies-Depression Scale (CES-D) – A 20-item instrument that allows patients to evaluate their feelings, behavior, and outlook from the previous week
In contrast to the above self-report scales, the Hamilton Depression Rating Scale (HDRS) is performed by a trained professional, not the patient. The HDRS has 17 or 21 items, scored from 0-2 or 0-4; a total score of 0-7 is considered normal, while scores of 20 or higher indicate moderately severe depression.
The Geriatric Depression Scale (GDS), although developed for older adults, has also been validated in younger adults. The GDS comprises 30 items; a short-form GDS has 15 items (see the images below).
Given that the commonly atypical presentation of depression in the elderly population can challenge even the most experienced clinician, rating scales in the elderly should be used and interpreted only in the context of a more thorough examination for depression.
Patients with major depressive disorder often complain of poor memory or concentration. This may be due to the depression itself or to an underlying dementia.
In older patients with established dementia, the Cornell Scale for Depression in Dementia (see the image below) can be used to determine the category and severity of depression. The clinician completes the scale on the basis of prior observation and interviews with the patient and the patient’s caregiver.
Laboratory Studies to Rule Out Organic Causes
Depression is a clinical diagnosis, based on the history and physical findings. No diagnostic laboratory tests are available to diagnose major depressive disorder, but focused laboratory studies may be useful to exclude potential medical illnesses that may present as major depressive disorder. These laboratory studies might include the following:
Complete blood cell (CBC) count
Thyroid-stimulating hormone (TSH)
Rapid plasma reagin (RPR)
Electrolytes, including calcium, phosphate, and magnesium levels
Blood urea nitrogen (BUN) and creatinine
Liver function tests (LFTs)
Blood alcohol level
Blood and urine toxicology screen
Dexamethasone suppression test (Cushing disease, but also positive in depression)
Cosyntropin (ACTH) stimulation test (Addison disease)
Neuroimaging can help clarify the nature of the neurologic illness that may produce psychiatric symptoms, but these studies are costly and may be of questionable value in patients without discrete neurologic deficits. Computed tomography (CT) scanning or magnetic resonance imaging (MRI) of the brain should be considered if organic brain syndrome or hypopituitarism is included in the differential diagnosis.
Positron emission tomography (PET) imaging provides the means for the study of receptor binding of certain ligands and the effect a compound may have on receptors. However, PET scanning is problematic for use with children and adolescents because it requires complex equipment and uses radiation.
Using single-photon emission computed tomography (SPECT) scanning, Tutus et al reported significant differences between the perfusion index values of untreated adolescents with depression and those of control patients. The researchers found that adolescents with major depressive disorder may have regional blood flow deficits in the left anterofrontal and left temporal cortical regions, with greater right-left perfusion asymmetry than healthy control patients. 
What would you like to print?
- Physical Examination
- Major Depressive Disorder
- Depression with Anxious Distress
- Depression With Melancholic Features
- Depression With Catatonia
- Atypical Depression
- Postpartum Depression
- Seasonal Affective Disorder
- Major Depressive Disorder with Psychotic Features
- Other Specificed Depressive Disorders
- Metabolic Depression
- Cultural Influences on Expression of Depression
- Suicidal Ideation
- Show All
- Approach Considerations
- Pharmacologic Therapy for Depression
- Electroconvulsive Therapy
- Bright-Light Therapy
- Additional Therapies for Depression
- Treatment-Resistant Depression
- Pediatric Depression Treatment
- Depression During Pregnancy
- Postpartum Depression Treatment
- Diet and Activity
- Complications of Treatment for Depression
- Long-Term Monitoring
- Show All