Depression: screening tools

Identifying depression in people with diabetes is vital if we are to optimise patient well-being as well as self-management of the condition. Screening tools are an essential part of the process of identifying individuals with depression but further investigations should be conducted before a clinical diagnosis of a depressive disorder can be confirmed. This section reviews some of the most widely used screening tools and provides information on their use in people with diabetes.

Current evidence indicates that approximately 10% of individuals with diabetes have clinically significant depressive disorders, with about one third suffering from depressive symptoms that may have a serious negative impact on quality of life. Over 80% of diabetes care is now provided in primary care and it is in this setting that there are key opportunities for screening and treating mental health problems.

However, depressive symptomatology often goes undetected and untreated. Furthermore diagnostic interviews (considered to be the gold-standard for identifying depression) are time-consuming, costly, and require training in their application. Brief screening instruments or questionnaires are quick and simple to administer and most have been shown to approximate clinically significant levels of depressive disorders at certain cut-points or scores. It should be remembered, however, that most screening tools are just that – they screen for symptoms of depression but are not intended for use as a diagnostic tool; they are merely a first step towards a definitive diagnosis usually using a clinical interview. The majority of available screening tools measure the presence or absence of depression, the type of symptoms present, and the severity of symptoms[1].

Routine depression screening in people with diabetes is feasible in different ways. The current risk of an individual with diabetes experiencing symptoms of depression can be assessed by the presence or absence of particular risk factors. A range of self-report screening tools have been devised for use in both research and clinical practice, many of which have been shown to measure symptoms that approximate clinical levels of depression (see Table 1).

Table 1: Symptoms of depression measured using self-report instruments
Feeling sad/depressed mood
Inability to sleep
Early waking
Lack of interest/enjoyment
Tiredness/lack of energy
Loss of appetite
Feelings of guilt/worthlessness
Recurrent thoughts about death/suicide

Many screening tools contain both cognitive and somatic symptoms of depression and these may or may not overlap with some of the symptoms of diabetes, especially when glycaemic control is poor or when the complications of diabetes (e.g. heart disease, diabetic retinopathy, kidney failure, peripheral neuropathy) start to develop. These symptoms include loss of or increase in appetite, difficulties sleeping, fatigue, loss of energy, and weight loss. The cognitive symptoms of depression may be affected by the experience of having diabetes; for example, individuals may have a fear of the future or have feelings of hopelessness that may be related to diabetes and its complications or may be linked to other aspects of their lives. It may be difficult therefore to disentangle reported symptoms which may relate to depression or to diabetes or even both. This is important because it may affect clinical decision-making and treatment recommendations.

There may also be differences in the applicability of different screening instruments in particular sub-groups, for example in older people, in men or women, and in certain cultural or ethnic minority groups. It is important to keep these issues in mind when deciding which instrument to use.

Screening for the symptoms of depression

The Patient Health Questionnaire – PHQ-9

One of the most common screening instruments used in countries such as the UK and the USA is the Patient Health Questionnaire - usually called the PHQ-9 [2]. As the name suggests there are 9 core items and patients are asked to indicate whether the particular symptoms of depression have been present in the previous two weeks.

The Patient Health Questionnaire - PHQ-9 sample questions:
Over the last 2 weeks how often have you been bothered by any of the following problems? (not at all/several days/more than half the days/nearly every day)
- little interest or pleasure in doing things
- feeling down, depressed, or hopeless
- trouble falling or staying asleep
- feeling tired or having little energy
- poor appetite or over eating

The PHQ-9 was devised in the USA for use in primary care and is based on the diagnostic criteria for major depressive disorder as described in the Diagnostic and Statistical Manual of Mental Disorders. There are two aspects to this tool; a nine-item screen to assess symptoms that have occurred during the last two weeks, followed by the determination of a symptom severity score to make a decision about the appropriate treatment. Scores of 10-14 on the 9-item screen are indicative of minor depression, scores of 15-19 are indicative of moderately severe depression and scores of 20+ indicate clinically significant levels of depression.

Possibly due to its relative brevity and ease of use, the PHQ-9 has been found to be acceptable in a number of different patient groups, including people with diabetes. It is easy to score and subsequently interpret. However, several items on the scale could be confounded by symptoms of diabetes, for example tiredness, lack of energy, poor appetite or overeating. The PHQ-9 is one of three screening instruments recommended by the English Department of Health for use in primary care and has also been used extensively in research settings.

The first two items of the PHQ-9 ask about the two core symptoms of depression as described by the DSM-IV criteria. These are used in English primary care as an initial screener for depressive symptoms.

  • During the last month, have you often been bothered by feeling down, depressed or hopeless?
  • During the last month, have you often been bothered by having little interest or pleasure in doing things?

Other commonly used screening tools in both research and clinical practice include the Hospital Anxiety and Depression Scale, the Centre for Epidemiologic Studies Depression Scale, and the Beck Depression Inventory.

The Centre for Epidemiologic Studies – Depression Scale (CES-D)

The CES-D[3] is the most commonly used in depression research[4]. It consists of a 20-item self-complete scale measuring the frequency of symptoms of depression during the past week, on a four-point scale ranging from ‘rarely or none of the time’ to ‘most or all of the time’. Higher CES-D scores indicate greater depressive symptomatology, with scores of 16 or higher being indicative of clinically significant levels of depression, and scores of 10-15 indicating moderate levels of symptomatology.

CES-D sample questions:
Using the scale below, indicate the number which best describes how often you felt or behaved this way – DURING THE PAST WEEK
1 = Rarely or none of the time (less than 1 day)
2 = Some or a little of the time (1-2 days)
3 = Occasionally or a moderate amount of time (-4 days)
4 = Most or all of the time (5-7 days)
During the past week:
- I was bothered by things that usually don’t bother me
- I felt that everything I did was an effort
- I enjoyed life
- I felt sad

The Hospital Anxiety and Depression Scale (HADS)

The HADS is a brief self-complete scale measuring the presence of symptoms of anxiety (7 items) and depression (7 items) during the past week[5]. It was designed for use in medically ill populations using only cognitive signs of depression. Because somatic symptoms are excluded this scale is useful for identifying depression in people with diabetes.

It has been used extensively with people with long term physical health problems, including diabetes and its utility and acceptability in people with diabetes as well as other long term conditions has been well demonstrated. It is also one of the screening tools recommended by the English Department of Health for use in primary care; however, it is rarely used because of the financial cost involved.

Hospital Anxiety and Depression Scale (HADS) sample questions:
Read each item below and underline the reply which closest to how you have been feeling in the past week.
I can laugh at the funny side of things
- as much as I always could
- not quite so much now
- Definitely not so much now
- Not at all
I feel cheerful
- Never
- Not often
- Sometimes
- Most of the time

HADS scores between 8 -10 are considered to approximate mild symptomatology, scores between 11 -14 indicate moderate symptoms; and scores of 15 or higher indicate severe symptomatology. The HADS, whilst originally designed for people with physical illness attending a medical setting, has also been validated for use in community settings. It is also sensitive to change both during the course of a physical illness and in response to intervention.

The Beck Depression Scale (BDI)

The BDI is a 21-item scale measuring depressive symptoms that have occurred in the past 2 weeks[6]. The BDI was originally developed in the 1960’s, however, it has more recently been updated in line with current diagnostic criteria and renamed the BDI – II.

Beck Depression Inventory (updated version, 1996) sample items:
Symptoms during the past two weeks
Item 1:
- I do not feel sad
- I feel sad much of the time
- I am sad all the time
- I am so sad or unhappy that I can’t stand it
Item 2:
- I am not discouraged about my future
- I feel more discouraged about my future than I used to be
- I do not expect things to work out for me
- I feel my future is hopeless and will only get worse
Item 16:
- I have not experienced any change in my sleeping pattern
- I sleep somewhat more than usual/ I sleep somewhat less than usual
- I sleep a lot more than usual/ I sleep a lot less than usual
- I sleep most of the day/I wake up 1-2 hours early and can’t get back to sleep

The Well-Being Index (WHO-5)

The WHO- 5 was first used by the WHO Collaborating Centre for Mental Health in Denmark[7]. This scale is often found to be more acceptable than other scales as it is a positive mood scale, measuring the absence rather than the presence of negative mood during the past two weeks. Scores below 13 indicate poor wellbeing and indicate the need for further investigation for depression.

The Well-Being Index (WHO-5)
Please indicate for each of the five statements which is closest to how you have been feeling over the last two weeks
(All of the time/Most of the time/More than half of the time/Less than half of the time/Some of the time/At no time)
1. I have felt cheerful and in good spirits
2. I have felt calm and relaxed
3. I have felt active and vigorous
4. I woke up feeling fresh and rested
5. My daily life has been filled with things that interest me
www.who-5.org/

Which screening tool to use?

When deciding which scale to use to screen for depression, there are a number of considerations, one of which is to the person administering the tool. Some scales, for example the PHQ-9, can be used without much training as long as the screener is fully aware that it is only a first-line screen and further clarification of the symptoms and need for referral and treatment is essential.

A further issue is the acceptability of screening by patients and practitioners. This is determined by several aspects regarding performance and content of the questions as well as the time demand for performing a screening measure. Well-being and diabetes-related distress questionnaires asking about diabetes related distress or general well-being may be better accepted by people with diabetes seeking medical treatment, because they may expect to be asked about diabetes related problems or well-being instead of depressed feelings and suicidal intentions. For health care professionals the time needed to score and interpret a screening result is important.

Conclusions

The evidence suggests that there are a number of screening instruments (not all of them identified here) which are useful in identifying symptoms of depression, albeit with the caveat that further investigations must be carried out in order to confirm a clinical diagnosis of depression. Screening tools such as those reviewed here are an essential part of that process and help to identify individuals who are in need of psychological care and treatment.

References

  1. ^ Lloyd CE, Pouwer F, Hermanns, N. Screening for depression and other psychological problems. Springer , London, 2013.

  2. ^ Spitzer RL, Kroenke K, Williams JB and the Patient Health Questionnaire Primary Care Study Group. Validation and utility of a self-report version of the PRIME-MD: the PHQ primary care study. JAMA 1999;1737-1744.

  3. ^ Radloff LS. A self-report depression scale for research in the general population. Applied Psychological Measurement 1977; 1:385-401

  4. ^ Roy T , Lloyd CE, Pouwer F, Holt RIG, Sartorius N. Depression Screening Tools used for measuring depression among people with type 1 and type 2 diabetes; a systematic review. Diabetic Medicine 2011 Vol 29, pp. 164–175

  5. ^ Snaith RP and Zigmond AS. Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 1983;361-370

  6. ^ Beck AT,Steer RA, Brown GK. Beck Depression Inventory manual(2nd edition). San Antonio, TX: Psychological Corporation,1996.

  7. ^ Bech P.Measuring the dimensions of psychological general well-being by the WHO-5. QoL Newsletter 2004; 32: 15-16.

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