Depression - Tests and diagnosis

The precise criteria for the diagnosisThe process of determining which condition a patient may have. of depression vary from country to country; however, they are always based on the symptoms of depression. A minimum number of symptoms are needed for diagnosisThe process of determining which condition a patient may have., and these should persist for a minimum period of time in order for a diagnosisThe process of determining which condition a patient may have. to be made, for example two or more weeks.

When you and your doctor are concerned that you may have depression, one of the most important aspects to determine is whether the symptoms are of clinical significance - that is, the doctor will need to know how long have they persisted for, and whether they impact on your daily living activities.[1]

Furthermore, it is important to differentiateThe specialisation of cells or tissues for a specific function. depression from, for example, healthy adjustment reactions to life events such as bereavement.[1]

Important aspects of depression that help to distinguish it from healthy reactions to life's stressors are as follows:[1]

  • Depression can be incapacitating, and can impact on all aspects of a person's life
  • Depression is associated with a distinct change in the person, compared with their self before they developed depression
  • There is the sense that these emotions differ from grief or general reactions to adversity.

It is helpful to remember the symptoms of depression when considering these features; read more about the symptoms of depression.

Your doctor might consider that you are more likely to develop depression if you have experienced episodes of depression in the past, or if there is a history of this condition in your family.[1]

The diagnosisThe process of determining which condition a patient may have. of depression is important because effective treatment is available. Criteria based on signs and symptoms are used to differentiateThe specialisation of cells or tissues for a specific function. depression from other mood disorders.[2] The under-diagnosisThe process of determining which condition a patient may have. of this condition can lead to a great deal of stressRelating to injury or concern..[3]

The important aspects of diagnosing depression include:

Clinical interview

If you have depression, simply speaking with your doctor will allow him or her to identify:[1]

  • The nature of any depressive symptoms, and how severe they are
  • The type of depression
  • Any life stressors, physical conditions or medications that may be making the depression worse
  • Any alcohol or substance issues
  • Any family history of depression
  • The degree of psychosocialRelating to psychological and social factors. support available to you from family and friends.

It is thought that the clinical interview may be less effective in identifying depression in older people.[4]

Physical examination

Physical examination and bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. tests are important to rule out any underlying medical disorder, and to determine whether such a medical disorder is actually the underlying cause of the depression.[1]

Screening

Screening questionnaires can help to identify depression, particularly in primary care. A number of these self-reported screening tests are available; however, they should always be followed up by actually speaking with your doctor about your symptoms and any concerns you may have.[1]

Examples of screening questionnaires include the Beck Depression Inventory and the Patient Health Questionnaire. The Beck Depression Inventory is a 21-point multiple choice questionnaire. The Patient Health Questionnaire scores nine criteria for depression from 0 (not present at all) to 3 (occurring nearly every day).[5]

However, one study in the Netherlands suggested that screening for depression is not effective, even among people at risk. This was largely because few people who were diagnosed went on to seek treatment.[6] It is important to recognise that treatment is available, and it can be very effective.

While such questionnaires cannot equal the value of a proper clinical assessment by your doctor, they can help to diagnose depression; it is well recognized that depression is frequently under-recognized in primary care, and indeed among all medical specialties.[3,7,8]

References

  1. http://www.searo.who.int/EN/Section1174/Section1199/Section1567/Section1826_8100.htmLast accessed January 6, 2010.
  2. Remick RA. Diagnosis and management of depression in primary care: a clinical update and review. CMAJ 2002; 167: 1253-60.
  3. Peveler R, Carson A and Rodin G. ABC of psychological medicine: Depression in medical patients. BMJ 2002; 325: 149-52.
  4. Crossett JHW. The best is yet to be: Preventing, detecting, and treating depression in older women. Journal of the American Medical Women's Association 2004; 59: 210-5.
  5. Lester H and Howe A. Depression in primary care: three key challenges. Postgrad Med J 2008; 84: 545-8.
  6. Baas KD, Wittkampf KA, van Weert HC et al. Screening for depression in high-risk groups: Prospective cohort study in general practice. The British Journal of Psychiatry 2009; 194: 399-403.
  7. Mitchell AJ, Vaze A and Rao S. Clinical diagnosisThe process of determining which condition a patient may have. of depression in primary care: a meta-analysis. Lancet 2009; 374: 609-19.
  8. Cepoiu M, McCusker J, Cole MG et al. Recognition of depression by non-psychiatric physicians-a systematic literature review and meta-analysis. J Gen Intern Med 2007; 23: 25-36.