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Diagnosing depression requires a detailed and long-term assessment as part of evidence-based practice. An initial evaluation of the symptoms helps determine suitable treatment options.
Moreover, a periodic assessment is required to track the progress of recovery and suitably alter the treatment methods for the best results.
While no laboratory tests are available to give a confirmed diagnosis of the condition, various tests have been developed to help rule out the depression in an individual.
The following tests will be performed to determine the presence of depression:
- Physical exam: The doctor may conduct a physical exam to check for signs of depression and inquire about your health issues.
- Medical history: The doctor will inquire if you have any family history of alcoholism, psychiatric illness, or depression. He may ask about asthma, allergies, epilepsy, tics, and other medical conditions.
- Lab test: A blood test may be conducted to check for medical conditions such as anemia, hyperthyroidism, and low levels of vitamin D that may cause depressive symptoms.
- Psychiatric evaluation: The mental health professional will evaluate your thoughts, feelings, emotions, and behavior using evidence-based questionnaires.
Diagnostic Criteria for Depression
The DSM-5 is a diagnostic tool considered to be the gold standard for clinicians and psychiatrists in assessing mental illness.
For an individual to receive a diagnosis of depression, the DSM-5 states that they must have at least five or more of the following symptoms during the same 2-week period and at least one of the symptoms is either depressed mood or loss of interest or pleasure:
- Depressed most of the day, nearly every day, as indicated by a subjective report (e.g., feels sad, empty, hopeless) or observation made by others (e.g., appears tearful).
- Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (as indicated by a subjective account or observation).
- Significant weight loss when not dieting or weight gain (e.g., change of more than 5% of body weight in a month) or a decrease or increase in appetite nearly every day.
- Insomnia or hypersomnia nearly every day.
- Psychomotor agitation or retardation nearly every day (observable by others, not merely subjective feelings of restlessness or being slowed down).
- Fatigue or loss of energy nearly every day.
- Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional) nearly every day (not merely self-reproach or guilt about being sick).
- Diminished ability to think or concentrate, or indecisiveness, nearly every day (either by a subjective account or as observed by others).
- Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide.
It is essential to understand that the DSM-5 should not be used as a replacement for sound clinical judgment, but rather an additional tool to help in the treatment of mental illness. (1)
It is vital that you receive a clinical diagnosis before reaching any definitive conclusions about your mental status. Symptoms that can be clearly attributable to another medical condition must not be included in the diagnosis of depression.
Instruments for Testing Depression
Various instruments are used to assess depression.
1. Beck Depression Inventory
The Beck Depression Inventory (BDI) is largely used for screening depression in people aged 13–80 years. The reliability and validity of this method have been tested in various populations all over the world.
BDI, which takes around ten minutes to complete, helps in measuring behavioral symptoms and severity of depression using 21 self-report rating items in the form of multiple-choice responses. (2)
2. Hamilton Depression Rating Scale
The Hamilton Depression Rating Scale (HAM-D) is the most frequently used, oldest, and most approved depression testing instrument. The HAM-D has various versions that can be employed by a clinician, the patient, or a computer upon training. (3)
The test takes about 20–30 minutes and is therefore highly useful for physicians with a tight schedule.
3. Montgomery-Åsberg Depression Rating Scale
The Montgomery-Åsberg Depression Rating Scale (MADRS) is used for assessing the severity of depression in patients aged 18 years and above. It involves 10 items that are rated on a 7-point scale and takes about 20–30 minutes to complete.
It is a modification of the HAM-D and has a higher sensitivity to change with time. (4)
4. The Center for Epidemiologic Studies Depression Scale (CES-D)
Developed for the general population, the Center for Epidemiologic Studies Depression Scale (CES-D) is a common instrument employed in primary care settings to test depression in individuals above 6 years of age. (5)
The scale has been evaluated for different cultures and genders and has been shown to be reliable and valid. This test takes about 20 minutes to complete.
Diagnosis is vital for the treatment of depression. Thus, it is essential to get a timely evaluation done.
Multiple tests are available for treating depression, many of which can be self-rated. However, it is best to consult an expert, since proper diagnosis requires set criteria to be followed.