Increased Psychiatric Complexity of Autism Spectrum Disorder: Explaining Diagnostic Inconsistencies

Thursday, May 11, 2017: 5:30 PM-7:00 PM
Golden Gate Ballroom (Marriott Marquis Hotel)
H. Tokadjian1,2, D. Sipsock3,4, C. McCormick1,2, K. A. Perkins1,5, L. Oberman1,4,6, T. F. Anders1,6, E. M. Morrow1,4,7 and S. J. Sheinkopf2,3,4, (1)Rhode Island Consortium for Autism Research and Treatment (RI-CART), Bradley Hospital, East Providence, RI, (2)Brown Center for the Study of Children at Risk, Women and Infants Hospital, Providence, RI, (3)Rhode Island Consortium for Autism Research and Treatment (RI-CART), East Providence, RI, (4)Department of Psychiatry & Human Behavior, Brown University, Providence, RI, (5)E. P . Bradley Hospital, East Providence, RI, (6)E. P. Bradley Hospital, East Providence, RI, (7)Department of Molecular Biology, Cell Biology and Biochemistry and Institute for Brain Science, Brown University, Providence, RI
Background: Recent studies have indicated that the Autism Diagnostic Observation Schedule (ADOS) has reduced specificity in samples with a broad range of developmental and behavioral disorders (Molloy et al. 2011), and a pilot study found that “false-positive” ADOS results may be attributable to symptoms of co-morbid psychiatric conditions (Stadnick et al. 2015). However, literature has yet to appropriately quantify phenotypic characteristics of individuals with diagnostic inconsistencies in ADOS and community diagnosis.

Objectives: To identify whether clinical characteristics differ in individuals with discordance between community diagnosis and ADOS as compared to individuals with concordance in these same measures.

Methods:  The sample was comprised of 762 individuals (ages 3 – 18; Mage = 13.27 years, SD = 9.45, 78.3% male) selected from a state-wide ASD registry. Participants entered the registry either with an existing diagnosis or due to a concern of an ASD. All participants were administered the ADOS-2 upon enrollment. Participants were grouped into four diagnostic categories depending on status of community diagnosis and ADOS-2 result: (1) Community ASD diagnosis and a positive ADOS-2 (N=533); (2) Community diagnosis and a negative ADOS-2 (N=54); (3) No community diagnosis and a positive ADOS-2 (N=109); and (4) No community diagnosis and a negative ADOS-2 (N=66). The presence of psychiatric diagnoses and the reports of current medications were obtained through caregiver-completed questionnaires. The number of different psychotropic medications were summed to create four dichotomous variables representing antidepressants, Attention-deficit/hyperactivity disorder (ADHD) medications, antipsychotics and mood stabilizers. Autism severity was measured by standardized scores available through a caregiver-completed Social Responsiveness Scale, Second Edition (SRS-2).

Results: A series of logistic regressions of co-morbid diagnoses with age and gender as covariates revealed that the discordant subgroups were more likely to have depression (χ² = 61.47, p < .001), anxiety (χ² = 51.93, p < .001), ADHD (χ² = 18.70, p = .002) and oppositional defiant disorder (χ² = 13.97, p = .016). Chi-square analyses revealed a significant difference between diagnostic groups and the likelihood of taking antipsychotic (p = .031) and ADHD (p = .020) medication. However, these effects did not survive follow-up logistic regression analyses controlling for age and gender. Further, there was a significant difference between diagnostic groups on SRS-2 severity (F(3,659) = 5.34; p = .001). Participants with a positive ADOS-2 result and community diagnosis scored higher on the SRS-2 compared to those with no ASD diagnosis (p= .003). Results support the sensitivity of the SRS-2 to measure ASD symptom severity in a subgroup more likely to have a true positive diagnosis.

Conclusions: Children presenting to an ASD registry with inconsistencies between community diagnosis and ADOS-2 findings had increased rates of caregiver-reported psychiatric diagnoses and psychotropic medications as compared to those whose ADOS-2 result was concordant with community diagnosis of ASD. The results concur with prior reports of reduced specificity of the ADOS-2 in the presence of co-occurring psychiatric symptoms. These findings are both empirically and clinically relevant, confirming the need for cautious interpretation of positive ADOS-2 results in the presence of psychiatric complexity.