Hospital Anxiety and Depression Scale

The Hospital Anxiety and Depression Scale (HADS), a self-assessment scale, was developed to detect states of depression, anxiety and emotional distress amongst patients who were being treated for a variety of clinical problems (Zigmond & Snaith 1983). The scale was not designed to be a clinically diagnostic tool (Whelan-Goodinson et al. 2009). Originally the scale consisted of eight questions relating to depression and eight relating to anxiety. Initial findings indicated that one of the items on the depressions scale was weak (r=0.11), thus it was removed. Remaining items on the scale had correlations ranging from +0.60 to +0.30, with a significance of (p<0.02). Anxiety items had correlations ranging from +0.76 to +0.41 (p<0.01); however, to keep the items in each scale equal, the weakest item on the anxiety portion of the scale was removed. Thus the final scale has a total of 14 items, with responses being scored on a scale of 0–3 (3 indicates higher symptom frequencies; (Whelan-Goodinson et al. 2009). Scores for each subscale (anxiety and depression) range from 0 to 21 with scores categorized as follows: normal 0–7, mild 8–10, moderate 11–14, and severe 15–21. Scores for the entire scale (emotional distress) range from 0 to 42, with higher scores indicating more distress. Prior to completing the scale patients are asked to “fill it complete in order to reflect how they have been feeling during the past week” (Zigmond & Snaith 1983; p. 366).

While many measures are used in the TBI population to assess depression and anxiety post injury, unfortunately, none of these measures have been evaluated for use with this population (Schonberger & Ponsford 2010; Whelan-Goodinson et al. 2009). Recently the HADS has been tested with those who have sustained an ABI; however due to the mixed aetiology problems were found with some of the questions which could be related to the injury itself, the level of cognitive impairment or the decreased speed at which information is processed (Dawkins et al. 2006; Johnston et al. 2000).

Table 27: Characteristics of the Hospital Anxiety and Depression Scale

Advantages. The HADS is brief and simple to use and although it was originally designed to be used with hospital populations it has been found to perform well with non-hospital groups (McDowell 2006). It has been found to take on average 2–5 minutes to complete and is completed by the patients themselves (Snaith 2003). The HADS requires the individual to respond to the question in relation to how they felt in the past week, thus it is therefore reasonable to re-administer the test again but only at weekly intervals. It has been found to perform as well as the BDI and the GHQ instruments. Overall, Mykletun et al. (2001) found the HADS scale possessed good “psychometric properties in terms of factor structure, intercorrelation, homogeneity and internal consistency” (p 543).

Limitations. When using the HADS to diagnosis depression or depressive symptoms post ABI, the sequelae of TBI may confound the test scores (Whelan-Goodinson et al. 2009). Caution is recommended when interpreting the results of these scales. Even though the HADS has been shown to be a reliable measure of emotional distress post ABI, the cut-off scores and categories have not been shown to be useful in predicting probable presence or “caseness” of depression or anxiety (Whelan-Goodinson et al. 2009).

Summary-Hospital Anxiety and Depression Scale

Interpretability: The results are easy to interpret with higher scores on each individual scale or the entire scale indicating greater anxiety, depression or mood disorders.

Acceptability: The HADS is widely accepted and used with most patient populations including those with a TBI.

Feasibility: The scale is readily available and can be used free of charge. It takes only a few minutes to complete, no specialized training is need to administer the test and may be completed by the patients themselves.

Table 28: Hospital Anxiety and Depression Scale Evaluation Summary

Reliability

Validity

Responsiveness

Rigor

Results

Rigor

Results

Rigor

Results

Floor/ceiling

+++

+++ (IC)

+++ (TR)

+++

+++(CV)

++ (CV-D)

+++ (DV)

+++

+++

N/A

NOTE: +++=Excellent; ++=Adequate; +=Poor; N/A=insufficient information; TR=Test Re-test; IC=Internal Consistency; IO=Interobserver