Parent report and behavioural observation tools are commonly used to assist with diagnosing autism spectrum disorders in childhood. However, in adulthood, these tools can be inappropriate and impractical. Self-report tools have been developed to address such limitations but rely upon insight into one’s impairments, which may be influenced by theory of mind, social impairments and intellectual functioning. The suitability of these tools for adults with autism spectrum disorder diagnoses thus remains unclear.
Objectives:
The aim of this study was to evaluate the diagnostic performance of commonly used self-report questionnaires among adults with Asperger disorder and whether theory of mind, intellect and social impairments influenced the insight required to effectively use these tools.
Methods:
51 adults with Asperger’s disorder and 25 adults without an autism spectrum disorder participated. Each participant completed the Ritvo Autism Asperger Diagnostic Scale-Revised (RAADS-R) and Autism-Spectrum Quotient (AQ). For each self-report questionnaire, standardised scores were calculated to reflect the extent of symptomatology reported. Scores for persons with Asperger’s disorder were then compared to standardised ratings of their symptomatology made by clinicians using the Autism Diagnostic Observation Schedule-Generic and DSM-IV-TR checklist for Asperger’s disorder and parents, spouses or caregivers who completed the Social Communication Questionnaire. Theory of mind, intellectual functioning (as indexed by verbal comprehension and perceptual reasoning), and social impairments were assessed using the social criteria from the DSM-IV-TR checklist and shortened forms of the Strange Stories Test and Wechsler Adult Intelligence Scale, fourth edition respectively. Moderated regressions were used to determine whether theory of mind, social impairments and intellect predicted one’s ability to accurately report one's symptomology (self-reporting insight); the degree of discrepancy between self and other rated symptomatology. The diagnostic performance of the self-report questionnaires was also assessed.
Results:
The RAADS-R had adequate sensitivity (.91) and specificity (.84). When using a cut-off of 26, the AQ performed with adequate sensitivity (.85) and specificity (.96). However, using the original cut-off of 32, sensitivity was reduced (.58) despite perfect specificity.
It was noted that some adults with Asperger’s Disorder substantially under or over-reported the extent of their symptomatology relative to clinicians, parents, caregivers and spouses. However, on average these discrepancies were slight. Collectively, social impairments, theory of mind and intellect were significant predictors of self-reporting insight evaluated against the DSM-IV-TR checklist and SCQ. The most consistent unique predictors of self-reporting insight for the AQ were social impairments and theory of mind. For the RAADS-R, the most consistent unique predictor of self-reporting insight was non-verbal IQ as indexed by perceptual reasoning ability.
Conclusions:
This study provides further support for the diagnostic suitability of the RAADS-R (Ritvo et al., 2010) and provides support for recommending a cut-off of 26 with the AQ (c.f.Woodbury-Smith, et al., 2005). Nevertheless, disparity in the ability to self-report among adults with Asperger’s disorder, which can be influenced by intellect, social impairments and theory of mind, may limit the suitability of self-report diagnostic measures for some individuals. Therefore, these tools should not be used in isolation when making diagnostic decisions.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype