Depression is set to be second only to cardiovascular disease in terms of the world's disabling diseases by the year 2020.
Major depressive disorder is associated with a high degree of personal disability, multiple morbidity, suicide and lost quality of life for patients, families and carers. Patients with chronic depression may also be high service users with significant economic implications.
Depression may not always be recognised by GPs whilst treating a patient's other chronic illnesses. It is, however, two or three times more common in patients with chronic diseases than in those who have good physical health. The Quality and Outcomes Framework (QOF) of the GP contract encourages the screening of patients with coronary heart disease (CHD) and diabetes for depression (Quality Indicator DEP1). In patients with a new diagnosis of depression, practices are also required to assess severity within 28 days of the initial diagnosis, using an assessment tool validated for use in primary care (Quality Indicator DEP2). A third indicator was introduced in 2009; for patients who had an assessment under the DEP2, a further assessment is required 5-12 weeks later.
This article deals only with screening for depression in primary care. See separate articles on Depression, Depression in Children and Adolescents and Postnatal Depression for details of epidemiology, investigations and management.
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Requirements of screening
For a system of screening to be viable it must fulfil certain criteria:
- The condition must be sufficiently common to merit screening. This does not necessarily mean common in the whole population unless there is universal screening. It means common in the target group for screening.
- There must be an effective intervention for the condition that is being sought.
- Screening must result in the condition being recognised at an earlier stage when intervention is more effective.
- There must be high specificity (low rate of false positives) and a very high sensitivity (very low rate of false negatives), although this is difficult to assess when evaluating a screening tool for depression.
- The screening test must be relatively cheap or else the cost per case detected is prohibitively expensive.
- It must be safe, easy to use and acceptable to the patient.
Who to screen
In one sense the General Medical Services' (GMS) contract has simplified the situation in identifying patients with coronary heart disease and diabetes as being prioritised for screening. However, practices still undertaking the National Enhanced Service are obliged to recognise depression at an early stage in any patient. This represents a considerable workload and it may be best to focus one's attentions on patients deemed to be 'at risk'.
National Institute for Health and Clinical Excellence (NICE) guidelines suggest screening in those with a past history of depression, significant physical illness - especially if it causes disability - and other mental health problems like dementia. Other situations where the chance of depression is very high include:
- Parkinson's disease where the disease is common but often missed.
- Dementia where the two diseases can easily resemble each other.
- The puerperium - screening may show positive results in as many as 13%.
- Alcoholism and drug abuse - it may be difficult to decide if depression is the cause or effect of substance abuse but it may be desirable to treat both.
- Victims of abuse.
- Physical disease like cancer, cardiovascular disease or diabetes.
- Chronic pain.
- Stressful home environments.
- The elderly.
- Social isolation.
- Unexplained symptoms.
Depression may be more difficult to detect in patients with physical illness because both conditions can have similar symptoms.
Screening and assessment tools
A number of screening and assessment tools have been validated and are generally available.
Initial screening in patients who may have depression
NICE recommends that any patient who may have depression (especially those with a past history of depression or who suffer from a chronic physical illness associated with functional impairment) should be asked the following two questions:
- During the last month have you been feeling down, depressed or hopeless?
- During the last month have you often been bothered by having little interest or pleasure in doing things?
If patients with a chronic physical illness answers 'yes' to either question, the following three questions should be asked:
During the last month, have you often been bothered by:
- Feelings of worthlessness?
- Poor concentration?
- Thoughts of death?
Assessing newly diagnosed patients
Three tools are recommended in the Quality and Outcomes Framework (QOF) guidance. These are:
- Patient Health Questionnaire (PHQ-9): this is a nine-item questionnaire which helps both to diagnose depression and to assess severity. It is based directly on the diagnostic criteria for major depressive disorder in the Diagnostic and Statistical Manual - Fourth Edition (DSM-IV). It takes about three minutes to complete. Scores are categorised as minimal (1-4), mild (5-9) , moderate (10-14), moderately severe (15-19) and severe depression (20-27). It can be downloaded free from the internet.
- Hospital Anxiety and Depression (HAD) Scale: despite its name, this has been validated for use in primary care. It is designed to assess both anxiety and depression. It takes about 5 minutes to complete. The anxiety and depression scales each have seven questions, and scores are categorised as normal (0-7), mild (8-10), moderate (11-14) and severe (15-21).
- Beck Depression Inventory® - Second Edition (BDI-II): this also uses DSM-IV criteria. it takes about five minutes to complete. It is an assessment of the severity of depression and is graded as minimal (0-13), mild (14-19), moderate (20-28) and severe (29-36). It consists of 21 items to assess the intensity of depression in clinical and normal patients. Each item is a list of four statements arranged in increasing severity about a particular symptom of depression. It is also not free but can be purchased from the supplier's website.
Other screening tests may be useful in particular situations. They include:
- Children's Depression Inventory (CDI) and Reynolds' Child Depression Scale (RCDS). Both of these can be used on children aged over 7.
- The Center for Epidemiologic Studies Depression Scale (CES-D) and Reynolds' Adolescent Depression Scale (RADS) are more suitable for adolescents.
- The Edinburgh Postnatal Depression Scale (EPDS) - a self-rating scale - is for puerperal depression.
- The Geriatric Depression Scale (GDS) is suitable for older patients. Center for Epidemiologic Studies (CES), Beck and Zung depression assessment tools can also be used in the elderly. See separate article Geriatric Depression Scale for further details.
- The Cornell Scale for Depression in Dementia (CSDD) is suitable for patients with dementia.
Although screening tools are useful, they should not be a substitute for clinical judgement. The patient's history, family history and the existence of comorbidities should be taken into account when diagnosing or assessing depression
Further reading & references
- Mental wellbeing and older people - guidance for occupational therapy and physical activity interventions to promote the mental wellbeing of older people in primary care and residential care, NICE Public Health Intervention Guidance (October 2008)
- Williams SB, O'Connor EA, Eder M, et al; Williams SB, O'Connor EA, Eder M, et al; Screening for child and adolescent depression in primary care settings: a systematic evidence review for the US Preventive Services Task Force. Pediatrics. 2009 Apr;123(4):e716-35.
- Mental health, National service frameworks and strategies, NHS Choices
- Sharp LK, Lipsky MS; Screening for depression across the lifespan: a review of measures for use in primary care settings. Am Fam Physician. 2002 Sep 15;66(6):1001-8.
- Murray CJ, Lopez AD; Alternative projections of mortality and disability by cause 1990-2020: Global Burden of Disease Study. Lancet. 1997 May 24;349(9064):1498-504.
- BMA Guidance; Quality and Outcomes Framework, 2009
- Depression with a chronic physical health problem, NICE Clinical Guideline (October 2009)
- Depression, Clinical Knowledge Summaries (February 2010)
- National Screening Committee UK; Criteria for appraising the viability, effectiveness and appropriateness of a screening programme, 2009
- Bick D, Howard L; When should women be screened for postnatal depression? Expert Rev Neurother. 2010 Feb;10(2):151-4.
- Boersma K, Linton SJ; Screening to identify patients at risk: profiles of psychological risk factors for early intervention. Clin J Pain. 2005 Jan-Feb;21(1):38-43; discussion 69-72.
- Depression in adults, NICE Clinical Guideline (October 2009)
- DEP2 Quality Indicator 2007, National Quality Measures Clearing House
- Patient Health Questionnaire (PHQ9) Screeners
- Hospital Anxiety and Depression (HAD) Scale, NHS Specialist Libraries; MS Word document
- Hospital Anxiety and Depression (HAD) Scale, GL Assessments; for purchase of questionnaire from copyright owners
- Beck Depression Inventory® - II (BDI® - II); Harcourt Assessment
- Children's Depression Inventory (CDI); Western Pyschological Services 2007
- Psychiatric Rating Scales for Depression; neurotransmitter.net; Links to various depression scales
- Edinburgh Postnatal Depression Scale, University of California, San Francisco
- Depression Screening Tools; Family Practice Notebook, 2000
|Original Author: Dr Laurence Knott||Current Version: Dr Laurence Knott|
|Last Checked: 20/04/2011||Document ID: 2701 Version: 26||© EMIS|
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