[Validity of the Scale of Pervasive Developmental Disorder in a Clinical Sample of Adults with Intellectual Disability].

OBJECTIVES: The study assesses the diagnostic validity of the Scale of Pervasive Developmental Disorder in Mentally Retarded Persons (PDD-MRS).

METHODS: Unblinded conduct of PDD-MRS in a clinical psychiatric sample of adults with intellectual disability (ID; N  = 109) and suspect of autism.

RESULTS: For a cut-off-score of 10, sensitivity was 89 %, specificity 62 % and the Area Under the Curve (AUC) 0.83. The total score was independent of age, gender and level of ID. However the diagnostic validity was better balanced in adults with mild to moderate ID (sensitivity/specificity: 85 %/73 %) compared to those with severe to profound ID (93 %/42 %). The SEAS-M total score was correlated with various ASD screening measures ( r  = .3-.6), while no correlation was found for scales assessing challenging behavior.

CONCLUSION: To conclude, the PDD-MRS is a screening instrument for diagnosing autism in adults with mild to moderate ID. Knowledge of the PDD-MRS results within the consensus conference may have led to an overestimation of its diagnostic validity.