Validation and adaptation of the Norwegian version of Hayes Ability Screening Index for intellectual difficulties in a psychiatric sample.

Background: Intellectual disabilities (ID) among psychiatric patients have traditionally been neglected. A lack of convenient instruments and competency in ID may have worsened the conditions and treatment availability for these patients. Aims: Validation and adaptation of a screening instrument for ID (Hayes Ability Screening Index; HASI) in a psychiatric hospital setting. Methods: This is a cross-sectional study of 50 psychiatric patients in two Norwegian psychiatric hospitals comparing results of the HASI with the Wechsler Abbreviated Scale of Intelligence (WASI). Results: The HASI correlated well with the standard IQ test used (r=0.67, P<0.001). At a stated cut-off score of 85, the HASI had a sensitivity of 100% and specificity of 34%. Conclusions: The HASI is a valid and time-saving screening instrument for ID among psychiatric patients. The prescribed cut-off score, however, resulted in a large number of false positives.