ReviewThe validity of the Hospital Anxiety and Depression Scale: An updated literature review
Introduction
To make cost-effective screening of mental disorders feasible, several brief questionnaires assessing a limited set of symptoms have been developed. The Hospital Anxiety and Depression Scale (HADS) [1] was developed by Zigmond and Snaith in 1983 to identify caseness (possible and probable) of anxiety disorders and depression among patients in nonpsychiatric hospital clinics. It was divided into an Anxiety subscale (HADS-A) and a Depression subscale (HADS-D) both containing seven intermingled items. To prevent ‘noise’ from somatic disorders on the scores, all symptoms of anxiety or depression relating also to physical disorder, such as dizziness, headaches, insomnia, anergia and fatigue, were excluded. Symptoms relating to serious mental disorders were also excluded, since such symptoms were less common in patients attending a nonpsychiatric hospital clinic. The authors [1] also intended to “define carefully and distinguish between the concepts of anxiety and depression.”
HADS has been used extensively, and we identified 747 papers that referred to HADS in Medline, ISI and PsycINFO indexed journals by May 2000.
The evaluation of psychometric properties and diagnostic efficacy of questionnaires is often inadequate [2]. To our knowledge, there has been only one review of the literature addressing these issues in HADS [3]. Based on approximately 200 papers on HADS in approximately 35,000 individuals in various patient populations, Herrmann concluded in 1996 that “HADS is a reliable and valid instrument for assessing anxiety and depression in medical patients.”
Since Herrmann's review the number of ‘HADS-papers’ that have been published has increased almost fourfold. These papers also include samples from the general population, which Herrmann's review did not. Another reason for conducting an updated review of HADS-related papers was to achieve more information about the following issues: (I) How is the factor structure, discriminant validity and the internal consistency of HADS? (II) How does HADS perform as a case finder for anxiety disorders and depression? (III) To what extent does HADS agree with other self-rating instruments (concurrent validity)?
Section snippets
Method
A search in the Medline, ISI and PsycINFO databases was performed in May 2000. All papers containing the terms ‘Hospital’ and ‘Anxiety’ and ‘Depression’ or ‘HAD’ or ‘HADS’ in the title or abstract were identified. The abstracts of these studies (n=1403) were then inspected to ascertain whether they contained information about the HADS. The authors then reviewed 747 studies using the HADS for information regarding issues (I), (II) and (III), and 71 relevant papers were identified.
Results
Most studies using HADS have been done on selected samples of patients with cancer or other somatic illnesses. The psychometric properties of HADS were seldom the main issue in these studies, the sample sizes were mostly relatively small (n<250), and the results were frequently given without further discussion. From general population samples, psychometric properties of HADS were only reported in three papers. Spinhoven et al. [8] reported from three different Dutch samples (total N=5393),
Bidimensionality
The results of our review support the two-factor structure of HADS. In most studies where empirically based exploratory factor analyses were used HADS revealed two relatively independent dimensions of anxiety and depression closely identical to the Anxiety and Depression subscales. The three-factor model supported by the theory-driven confirmatory factor analysis of Dunbar et al. [11], however, challenge the bidimensionality of HADS. Nevertheless, the fit measures of the two-factor model
Conclusions
This review confirmed the assumption that HADS is a questionnaire that performs well in screening for the separate dimensions of anxiety and depression and caseness of anxiety disorders and depression in patients from nonpsychiatric hospital clinics. Even though a limited number of studies addressed other study populations, we found evidence that HADS has the same properties when applied to samples from the general population, general practice and psychiatric patients. HADS seems to have at
References (86)
International experiences with the Hospital Anxiety and Depression Scale—a review of validation data and clinical results
J Psychosom Res
(1997)- et al.
The structure of the Hospital Anxiety and Depression Scale (HAD): an appraisal with normal, psychiatric and medical patient subjects
Pers Individ Differ
(1997) - et al.
Anxiety and depression in patients with chest pain referred for exercise testing
Lancet
(1985) - et al.
Somatization: a transcultural study
J Psychosom Res
(1995) - et al.
A prospective study of psychosocial morbidity in adult bone marrow transplant recipients
Psychosomatics
(1994) - et al.
Screening for major depression disorders in medical inpatients with the Beck Depression Inventory for Primary Care
Behav Res Ther
(1997) Comparison of three instruments for measuring patient anxiety in a coronary care unit
Intensive Crit Care Nurs
(1993)- et al.
Assessment of preoperative anxiety: comparison of measures in patients awaiting surgery for breast cancer
Br J Anaesth
(1995) - et al.
Somatization and somatosensory amplification in psychiatric outpatients: an explorative study
Compr Psychiatry
(1997) - et al.
A validation study of three anxiety and depression self-assessment scales
J Psychosom Res
(1987)