Autism Spectrum Disorder and Schizophrenia Are Better Differentiated by Positive Symptoms Than Negative Symptoms.

Dominic A Trevisan,Adam J Naples,James C Mcpartland,Alan Anticevic,Jennifer H Foss-Feig,Vinod Srihari

doi:10.3389/fpsyt.2020.00548

Dominic A Trevisan, Adam J Naples + Show 4 more

Open Access

https://doi.org/10.3389/fpsyt.2020.00548

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Abstract

Autism spectrum disorder (ASD) and schizophrenia (SZ) are heterogenous neurodevelopmental disorders that overlap in symptom presentation. The purpose of this study was to specify overlapping symptom domains and to identify symptoms that can reliably differentiate adults with ASD (n = 53), SZ (n = 39), and typical development (TD; n = 40). All participants regardless of diagnosis were administered gold-standard diagnostic assessments of ASD and SZ characteristics including the Autism Diagnostic Observation Schedule (ADOS-2) and the Positive and Negative Syndrome Scale (PANSS). Sensitivity and specificity of the ADOS were assessed using diagnostic cut-off scores. The degree of symptom overlap on these measures between participant groups was analyzed using Analyses of Variance (ANOVAs), Receiver Operating Characteristic (ROC) Curves, and Analyses of Covariance (ANCOVAs) to control for group differences in IQ and sex distributions. The ADOS reliably discriminated ASD and TD adults, but there was a high rate of “false positives” in SZ patients who did not meet the DSM-5 criteria for ASD. To identify the reasons for low specificity in the SZ sample, we categorized ASD and SZ symptoms into ‘positive’ (presence of atypical behaviors) and ‘negative’ (absence of typical behaviors) symptoms. ASD and SZ groups overlapped on negative symptoms largely related to the absence of typical social and communicative behaviors, whereas disorder-specific positive symptoms differentiated ASD and SZ. For example, those with ASD scored higher on restricted and repetitive behaviors and stereotyped language, whereas those with SZ scored higher on psychotic symptoms such as delusions and hallucinations. These results suggest that, when making a differential diagnosis between ASD and SZ, clinicians may benefit from focusing on the presence or absence of positive ASD and SZ symptoms. Standardized measures to classify ASD symptoms into positive and negative symptoms have not yet been developed but represent a potentially viable clinical tool.

Highlights

Autism spectrum disorder (ASD) and schizophrenia (SZ) are neurodevelopmental disorders with heterogeneous and sometimes, overlapping symptom presentation [1,2,3,4,5]
The Areas under the curve (AUC) for the entire sample was .84, p < .001, suggesting ADOS algorithm scores are a good test for discriminating ASD from the combined typical development (TD) and SZ groups according to Metz’s [42] standards
While the specificity of the Autism Diagnostic Observation Schedule-2nd edition (ADOS-2) was perfect (100%) in classifying TD participants, there was a high percentage of SZ false positives, such that 43.59% of participants with SZ met ADOS-2 criteria for autism or autism-spectrum despite not meeting clinical DSM-5 criteria for ASD

Summary

Introduction

Autism spectrum disorder (ASD) and schizophrenia (SZ) are neurodevelopmental disorders with heterogeneous and sometimes, overlapping symptom presentation [1,2,3,4,5]. A rare and severe autistic disorder known as “childhood disintegrative disorder” (CDD; previously known as Heller’s syndrome) characterized by developmental regression, was frequently associated with what is presumed to be paranoia and psychosis [19] Psychotic symptoms, such as delusions and auditory hallucinations have been observed in less impaired people with ASD and in what was previously termed “Asperger syndrome” [20,21,22] these autism subtypes (CDD and Asperger syndrome) are subsumed under “autism spectrum disorder” as of DSM-5 [1], these findings demonstrate that psychotic symptoms can be associated with the full spectrum of autism severity

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