Objectives: The current study aims to investigate the psychometric qualities of the ADOS module 4 with respect to the classification and the domains.
Methods: The ADOS module 4 was administered to 93 males aged 18 through
Results: ANOVA’s showed significant main effects of group on the social and communication subdomains. Post-hoc tests showed that the group with ASD scored significantly higher compared to the Psychopathy group (p<0.005) and the Control group (p <0.001) on both domains. The group with Schizophrenia also scored significantly higher than the control group (p=0.05) on Communication and higher than the Psychopathy (p<0.05) and the Control group (p<.005) on the Social domain. Compared to the group with Schizophrenia, the group with ASD did not score higher on the Communication (p=.471) nor Social domain (p=.118). However, when comparing the participants with AD (n=8) with the group with Schizophrenia, the group with AD did obtain higher scores on the social domain (p=.026, Mann-Whitney U-test). Outcome on the ADOS for participants with Schizophrenia was related to their scores on the Positive and Negative Symptom Scale (PANNS): more negative symptomatology was associated with higher scores on the social domain (r=.586, p<.05) and total score (r=.553, p<.05).
Conclusions: The ADOS module 4 assists the clinician in differentiating ASDs from Psychopathy and from persons with no clinical diagnosis. Additionally, autism is distinguishable from Schizophrenia on the social domain. Difficulties in distinguishing ASDs from Schizophrenia seem to be related to the nature of both disorders and to the relatively high-functioning ASD group in this study.