People with intellectual disability often face barriers accessing mainstream psychological services due to a lack of reasonable adjustments, including the absence of adapted versions of routine outcome measures. Adapted versions of the Patient Health Questionnaire-9 (PHQ-9) and the Generalised Anxiety Disorder-7 (GAD-7) have been created for adults with ID.

This study aims to evaluate the psychometric properties of the adapted PHQ-9 and GAD-7.

The adapted PHQ-9 and GAD-7 and the Glasgow Depression and Anxiety Scales (GDS-ID, GAS-ID) were administered to 47 adults (n=21 clinical group; n=26 community group) with ID. Cross-sectional design and between-group analyses tested for discriminant validity. Concurrent and divergent validity was tested using correlational designs. Reliability was investigated by internal consistency and test–retest analysis.

The clinical group scored significantly higher on the adapted PHQ-9 (t45=–2.28, p=.03, 95% CI [–7.09, –.45]) and GAD-7 (t45=–3.52, p=.001, 95% CI [–7.44, –2.02]) than the community group, evidencing discriminant validity. The adapted PHQ-9 correlated with the GDS-ID (r47=.86, p<.001) and the adapted GAD-7 correlated with the GAS-ID (r46=.77, p<.001). The adapted PHQ-9 (Cronbach’s α=.84, ICC=.91) and GAD-7 (Cronbach’s α=.86, ICC=.77) had good internal consistency and test–retest reliability.

Preliminary research suggests the adapted PHQ-9 and GAD-7 are valid and reliable measures. They could provide a reasonable adjustment for the minimum dataset used in NHS Talking Therapies and can be easily administered in routine clinical practice. Further work to establish additional psychometric properties is now required.