Tests Used to Diagnose Depression
Diagnosing Depression and Other Testing Methods
The doctor may include other standard tests as part of the initial physical exam. Among them may be blood tests to check electrolytes, liver function, toxicology screening, and kidney function. Because the kidneys and liver are responsible for the elimination of depression medications, impairment to either of these two organs may cause the drugs to accumulate in the body.
Other tests may include:
- CT scan or MRI of the brain to rule out serious illnesses such as a brain tumor
- Electrocardiogram (ECG), which is used to diagnose some heart problems
- Electroencephalogram (EEG), which uses an apparatus for recording electrical activity of the brain
Depression Screening Tests
After discussing your mood and the way it affects your life, your doctor may also ask you questions that are used specifically to screen for depression. It's important to keep in mind that the inventories and questionnaires the doctor may use are just one part of the medical process of diagnosing depression. These tests, however, can sometimes give your doctor better insight into your mood. He or she can use them to make a diagnosis with more certainty.
One example of a screening test is a two-part questionnaire that has been shown to be highly reliable in identifying the likelihood of depression. When you take this test, you will be asked to answer two questions:
- 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?
Your answer to the two questions will determine what the doctor does next. The doctor may ask you additional questions to help confirm a diagnosis of depression. Or if your answers indicate you do not have depression, the doctor may review your symptoms again to continue the effort to find the cause. Studies show that these two questions, especially when used with another test as part of the assessment process, are highly effective tools for detecting most cases of depression.
Your doctor may use other depression screening instruments as well. Examples include:
- The Patient Health Questionnaire-9 (PHQ-9) -- a 9-item self-administered diagnostic screening and severity tool based on current diagnostic criteria for major depression
- Beck Depression Inventory (BDI), -- a 21-question multiple-choice self-report that measures the severity of depression symptoms and feelings
- Zung Self-Rating Depression Scale -- a short survey that measures the level of depression, ranging from normal to severely depressed
- Center for Epidemiologic Studies-Depression Scale (CES-D) -- an instrument that allows patients to evaluate their feelings, behavior, and outlook from the previous week
- Hamilton Rating Scale for Depression (HRSD), also known as the Hamilton Depression Rating Scale (HDRS) or abbreviated to HAM-D -- a multiple choice questionnaire that doctors may use to rate the severity of a patient's depression
When you take a test or inventory, you may feel uncomfortable responding honestly to questions or statements that are made. The person who administers the test will be asking about depression and mood, depression and cognition, and the physical feelings of depression such as lack of energy, sleep disturbance, and sexual problems. Try to be as honest as you can when assessing your symptoms. Questionnaires and screening tools can help a mental health professional in making a diagnosis, but rating scales in themselves are not a substitute for a clinical diagnosis made from a thorough interview. Once your doctor has made an accurate diagnosis he or she can then prescribe an effective treatment.