The psychiatric assessment schedule for adults with developmental disability checklist: reliability and validity of Turkish version

Aim/background: There is a lack of psychometric instruments to measure psychopathology in people with intellectual disabilities (ID). This may lead to underdiagnosis of treatable psychiatric comorbidities in this population. Psychiatric assessment schedule for adults with developmental disabilities (PAS-ADD) Checklist was developed as a screening tool designed for lay people. The PAS-ADD Checklist was created in English and was later on validated for other languages, including French and German. There is no psychometric measure available in Turkish to screen for or detect psychiatric symptoms in adults with ID. The aim of the present study was to present a psychometric evidence of the Turkish language version of the PAS-ADD Checklist. This is the first study aiming to present and validate a psychiatric screening instrument for adults with ID in Turkey. Methods: The Turkish version was developed by translation and back translation. The checklist and a structured purpose-designed socio-demographic form were administered to 151 adult individuals with ID of whom 71 were living in care homes, 80 at family home. They all underwent face-to-face psychiatric assessment through clinical examination. The Turkish version of the Checklist was compared with the original English and other language versions, and the psychometric properties were presented. Internal consistency, test-retest reliability, inter-rater reliability, factorial analysis and sensitivity/specificity were calculated. Results: The validity and reliability of the Turkish version seem acceptable with good psychometric properties. The item analysis of the total scale showed strong consistency with Cronbach's alpha of 0.75. Test-retest reliability for different items (rs: between 0.50 and 0.69) was better than inter-rater reliability (rs: between -0.15 and 0.75) which could be expected given that raters are non-specialist people. Sensitivity and specificity were calculated for the number of participants who did and did not cross threshold and for whom a psychiatric disorder was or was not present. The sensitivity was 78.7% and specificity was 78.8%. An explanatory principal component factor analysis was conducted on the Turkish version of the Checklist revealed six factors. This six-factor solution explained 54% of variance. The likely reasons for the findings are discussed. Conclusion: Overall, the Turkish version of the PAS-ADD Checklist is an acceptable generic screening tool considering the difficulty of detecting mental health problems in people with ID and the lack of Turkish screening instrument. The Turkish version of the PAS-ADD Checklist can be recommended as a general screening tool for psychiatric disorders in adults with ID. It will contribute to early diagnosis and management of mental health problems and therefore improve the quality of life of those with ID and their family/care givers.