The diagnostic boundary between autism spectrum disorder, intellectual developmental disorder and schizophrenia spectrum disorders

Abstract

Purpose – During the last few years the prevalence of autism and Autism Spectrum Disorder (ASD) has increased greatly. A recurring issue is the overlap and boundaries between Intellectual Developmental Disorder (IDD), ASD and Schizophrenia Spectrum Disorders (SSD). In clinical practice with people with IDD, the alternative or adjunctive diagnosis of ASD or SSD is particularly challenging. The purpose of this paper is to define the boundaries and overlapping clinical characteristics of IDD, ASD and SSD; highlight the most relevant differences in clinical presentation; and provide a clinical framework within which to recognize the impact of IDD and ASD in the diagnosis of SSD. Design/methodology/approach – A systematic mapping of the international literature was conducted on the basis of the following questions: first, what are considered to be core and overlapping aspects of IDD, ASD and SSD; second, what are the main issues in clinical practice; and third, can key diagnostic flags be identified to assist in differentiating between the three diagnostic categories? Findings – Crucial clinical aspects for the differentiation resulted to be age of onset, interest towards others, main positive symptoms, and anatomical anomalies of the central nervous system. More robust diagnostic criteria and semeiological references are desirable. Originality/value – The present literature mapping provides a comprehensive description of the most relevant differences in the clinical presentation of ASD and SSD in persons with IDD.

The morphometric co‐atrophy networking of schizophrenia, autistic and obsessive spectrum disorders

“…The psychotic manifestations of SCZD, especially the negative and catatonic ones, are so much associated with the social withdraw and communicative difficulty in ASD that even specific tests, such as the Autism Diagnostic Observation Schedule (ADOS), sometimes fail and produce false positives if performed on adolescent patients with SCZD (Bertelli, et al, ). Furthermore, psychotic manifestations and ASD are frequently observed in the clinical practice, and it is particularly worth noting that some patients, diagnosed with ASD in their childhood, show a schizophrenic development in adolescence or adulthood, accompanied by psychotic and neurodegenerative aspects (Keller, Piedimonte, Bianco, Bari, & Cauda, ).…”

Are schizophrenia, autistic, and obsessive spectrum disorders dissociable on the basis of neuroimaging morphological findings?: A voxel‐based meta‐analysis

“…The disruption of the functional integrity of this network would account for the executive deficits that are observed across psychiatric conditions. This study provides the intriguing suggestion that a network organizing model capable of accounting for the role of shared neural alteration patterns across different brain disorders would be very useful for any aspect of clinical practice, from diagnosis to prognosis and treatment [Bertelli et al, ].…”

Assessment of psychosis in ASD/ID: a case study

“…The identification of psychiatric disorder in people with autism spectrum disorder (ASD) and intellectual disability (ID) poses considerable challenges, such as: there are few appropriate assessment tools; symptoms of ASD may be difficult to separate from symptoms of psychiatric disorder; and people with ASD and ID usually have difficulties in self-report Underwood et al, 2015). Differentiating ASD and psychosis seems to be particularly challenging (Bertelli et al, 2015;Bakken and Høidal, 2014).…”