The psychometric properties of the hospital anxiety and depressions scale adapted for use with people with intellectual disabilities

Background There is increasing recognition of depression in people with intellectual disabilities (ID). There is a need to develop well-standardised self-report measures for both clinical and research purposes. This paper presents some psychometric properties of the Hospital Anxiety and Depression Scale (HADS) adapted for use with people with ID. The anhedonic emphasis in the depression scale of the HADS may be particularly useful for people with ID who present with high rates of physical co-morbidity.

Method A total of 197 people with ID completed an adapted HADS; 32 participants also completed the Zung Depression Scale and 42 also completed the Glasgow Depression Scale.

Results The obtained factor structure is similar to the original form of the scale used with people without ID. However, the underlying question wording of the HADS, where most depression items are phrased positively and most anxiety items are phrased negatively, makes clear interpretation of the factor structure difficult. The HADS has an adequate internal reliability and correlates well with other self-report measures of depression.

Conclusions The HADS may need further adaptation; however, the measurement of anhedonia is a useful addition to the self-report measures of depression available for people with ID.