Social adaptive skills and psychopathology in adults with intellectual disabilities of non-specific origin and those with Down syndrome.

The present study aimed to assess the psychometric proprieties of a new social adaptive skills questionnaire and examine the impact of maladaptive behaviour on social functioning in adults with ID of non-specific aetiology and those with Down syndrome. The results of an exploratory factor analysis led to the exclusion of 20 items out of 48 and yielded a four-factor structure. The Confirmatory Factor Analysis conducted on 28 remaining items confirmed a four-factor structure explaining 43% of the total variance. The results computed on the global sample (n = 567) showed a "very good" internal consistency for the global score (.89) for all four factors with a very good fit (.97). Thus, this new assessment tool presented a good conceptual validity for assessing social-adaptive skills in adults with ID. The results also showed that participants with DS (no = 92) exhibited a higher global score of social adaptive skills on three subscales (sociability, social relating and respect for social rules) compared to adults with ID of non-specific aetiology (no = 328), and presented a lower level of psychopathology problems. Although aetiology was significantly related to these group differences even after controlling for level of ID and chronological age, the general level of psychopathology fully mediated these relations. In conclusion, the regression coefficient analyses showed that the general level of psychopathology fully mediated the relationship between aetiology and social adaptive skills. A combined assessment of these dimensions should provide information about their predictive value for social functioning in ID adults and target specific remediation goals.