Screening for Anxiety in People with an Intellectual Disability: German Version of the "Glasgow Anxiety Scale for People with an Intellectual Disability" (GAS-ID)

Objective: As of yet, there exists no German-language self-rating questionnaire as a screening for anxiety disorders in people with an intellectual disability. Therefore the Glasgow Anxiety Scale for people with an Intellectual Disability (GAS-ID) was translated into German and its psychometric properties were assessed.

Methods: Internal consistency and concurrent validity were tested in 34 adults with learning difficulties and mild and moderate intellectual disability. Convergent validity was estimated by using data from a clinical sample of 38 persons without intellectual disability.

Results: The GAS-ID discriminates between intellectually disabled subjects with an anxiety disorder and subjects without comorbid mental disorders resulting in a sensitivity of 100 % and a specificity of 87 %. It also demonstrates a very good internal consistency (Cronbachs α = 0.90) and a high convergent validity (with BAI: r = 0.76).

Conclusions: The German GAS-ID is a reliable, valid and economically applicable self-report screening instrument for assessing anxiety in people with intellectual disability. However, minor revision of items and future research is needed to investigate the validity of the GAS-ID.