The following are studies that have been conducted by the author (Steve Moss) and his colleagues. Many other studies have also used the PAS-ADD system.
PAS-ADD Clinical Interview
The validity of PAS-ADD in relation to the clinical opinion of referring psychiatrists was reported by Moss, Prosser and Goldberg (1996) and Moss et al (1997). Inter–rater reliability of the lCD–10 version gave a mean Kappa of 0.65 for individual item codes of, and Kappa 0.7 for agreement on index of definition (clinical significance of the symptoms) (Costello et al, 1996). The relationships between respondent (patient) and informant reports of symptoms, and the implications of deriving diagnoses solely from informant interviews, are discussed in Moss, Prosser, lbbotson and Goldberg (1996). The issues of using care staff as informants are discussed in Moss and Patel (1993).
The investigations conducted during the original development of the Mini PAS-ADD are reported in Prosser et al (1998). Regarding reliability, we generally found a high level of agreement between ratings conducted by (a) a group of psychiatrists, and (b) a group of community service personnel. The agreement on case versus non-case was over 90% for disorders covered fully by the Mini PAS-ADD.
An estimate of validity investigated whether the community service team members, using the Mini PAS-ADD, could correctly identify cases identified by an independent group of expert clinicians. They broadly achieved a very good level of performance in this respect. The percentage of correct classifications was, as would be expected, lower than that of the psychiatrist raters (81% versus 91%).
A much larger scale study has been completed in Belgium, using over 70 trained users of the Mini PAS-ADD. Results of this study are yet to be published. However, it can be reported that inter–rater reliability was found to be extremely high.
Factor analysis of the Checklist completed on a community sample of 201 individuals yielded eight factors, of which seven were readily interpretable in diagnostic terms. Internal consistency of the scales was generally acceptable. Inter–rater reliability in terms of case identification, the main purpose of the Checklist was quite good, 83% of the decision being in agreement. Validity in relation to clinical opinion was also satisfactory, case detection rising appropriately with the clinically judged severity of disorder (Moss et al, 1998). Subsequent independent studies have further investigated the Checklists’ psychometric properties (Sturmey et al, 2005) and established norms for an adult sample (Taylor et al, 2004).
Costello H, Moss SC, Prosser H & Hatton C (1997) Reliability of the ICD-10 version of the Psychiatric Assessment Schedule for Adults with Developmental 5–9 Disability (PAS-ADD), Social Psychiatry and Psychiatric Epidemiology 32 339–343.
Moss SC, Goldberg D, Patel P & Wilkin D (1993) Physical morbidity in older people with moderate, severe and profound mental handicap, and its relation to psychiatric morbidity. Social Psychiatry and Psychiatric Epidemiology 28 32–39.
Moss SC & Patel P (1993) Prevalence of mental illness in people with learning disability over 50 years of age, and the diagnostic importance of information from carers. Irish Journal of Psychiatry 14 110–129.
Moss SC, Patel P, Prosser H, Goldberg DP, Simpson N, Rowe S & Lucchino R (1993) Psychiatric morbidity in older people with moderate and severe learning disability (mental retardation). Part I: Development and reliability of the patient interview (the PAS- ADD). British Journal of Psychiatry 163 471–480.
Moss SC & Patel P (1995) Psychiatric symptoms associated with dementia in older people with learning disability. British Journal of Psychiatry 167 663–667.
Moss SC, Ibbotson B, Prosser H, Goldberg DP, Patel P & Simpson N (1997) Validity of the PAS-ADD for detecting psychiatric symptoms in adults with learning disability. Social Psychiatry and Psychiatric Epidemiology 32 344–354.
Moss SC, Prosser H & Goldberg DP (1996) Validity of the schizophrenia diagnosis of the Psychiatric Assessment Schedule for Adults with Developmental Disability (PAS- ADD). British Journal of Psychiatry 168 359–367.
Moss SC, Prosser H, Ibbotson B & Goldberg DP (1996) Respondent and informant accounts of psychiatric symptoms in a sample of patients with learning disability. Journal of Intellectual Disability Research 40 457–465.
Moss SC, Prosser H, Costello H, Simpson N, Patel P, Rowe S, Turner S & Hatton C (1998) Reliability and validity of the PAS-ADD Checklist for detecting psychiatric disorders in adults with intellectual disability. Journal of Intellectual Disability Research 42 173–183.
Patel P, Goldberg DP & Moss SC (1993) Psychiatric morbidity in older people with moderate and severe learning disability (mental retardation). Part II: the prevalence study. British Journal of Psychiatry 163 481–491.
Prosser H, Moss SC, Costello H, Simpson N, Patel P & Rowe S (1998) Reliability and validity of the Mini PAS-ADD for assessing psychiatric disorders in adults with intellectual disability. Journal of Intellectual Disability Research 42 264–272.
Sturmey P, Newton JT, Cowley A, Bouras N & Holt G (2005) The PAS-ADD Checklist: Independent replication of its psychometric properties in a community sample. British Journal of Psychiatry 186 319–323.
Taylor J, Hatton C, Dixon L & Douglas C (2004) Screening for psychiatric symptoms: PAS-ADD Checklist norms for adults with intellectual disabilities. Journal of Intellectual Disability Research 48 37–41.
Wing JK, Sartorius N & Ustun TB (Eds) (2011, in press) Diagnosis and Clinical Measurement in Psychiatry. Cambridge: Cambridge University Press.
Wing JK (1996) SCAN and the PSE tradition. Social Psychiatry and Psychiatric Epidemiology 31 50–54.
World Health Organization (1992) Schedules for Clinical Assessment in Psychiatry (SCAN1).Geneva: WHO.
World Health Organization (1994) Schedules for Clinical Assessment in Psychiatry (SCAN 2.0). Geneva: WHO.