Asperger syndrome and schizophrenia: Νeurodevelopmental continuum or separated clinical entities?

Abstract

This article is an overview of the literature on Asperger's syndrome and schizophrenia and aim to discuss their similarities and differences. Eugen Bleuler who associated the terms "schizophrenia" and "autism" a century ago, viewed autism as a form of solitude of schizophrenic patients representing withdrawal from reality. Ever since, there has been confusion as to the boundaries between these conditions. Nowadays recent research, from a variety of perspectives-genomics, neurodevelopment, psychiatry, etc. has given new information on these conditions. It is easier to demarcate these two disorders at the extremes, but it is extremely difficult dissociating milder forms of both disorders. Asperger's syndrome (AS), is considered to be a continuous and lifelong disorder with strong heritability, present from early childhood. It is included within the category of autism spectrum disorders and it is usually diagnosed in childhood. Patients with Asperger syndrome are often diagnosed late or they are considered as having schizophrenia. Misdiagnosing Asperger syndrome creates severe problems by preventing effective therapy. A lot of clinical characteristics of Asperger's syndrome are also present in schizophrenia, such as impaired social interaction, disabilities in communication and restricted interests. On the other side some clinical features may facilitate the differential diagnosis, such as the younger age at onset, family history of pervasive developmental disorders, pragmatic aspects of language use, lack of imagination, ect. It is known that symptoms of Asperger's syndrome have some overlap with those of schizophrenia, but less is known about comorbidity between these two syndromes. It is still a question whether autism spectrum disorders in young children can increase the risk for the development of schizophrenia and other psychotic disorders, later in life. Both disorders are of neurodevelopmental origin and genetic factors are prominent. In both neurocognitive deficits as well as deficits in social cognition and social functioning are marked. The boundaries between AS and schizophrenia are still not clear even if this distinction is necessary for the appropriate treatment of the patient and his family. For the writing of the literature review, the following electronic databases were used: PubMed, Scopus, Psycinfo, Cochrane Library, Web of Science and Google Scholar. The key words used were: Asperger's syndrome, schizophrenia, children and adolescents, differential diagnosis, autism spectrum disorders.

Anomalous brain gyrification patterns in major psychiatric disorders: a systematic review and transdiagnostic integration

“…ASD patients have different developmental signs (e.g., pragmatic aspects of language use and lack of imagination) than SCZ patients 146 , which may be due to a distinct genetic mechanism. Autistic symptoms, such as impaired social reciprocity and communication, in ASD children may partly be explained by parietal gyral pattern changes.…”

Social Cognition in Schizophrenia and Autism Spectrum Disorders: A Systematic Review and Meta-Analysis of Direct Comparisons

“…All in all, it remains unsettled whether or not schizophrenia and ASD differ in terms of social cognitive performance ( 1 ), with their shared genetic risk, partly overlapping pathogenic mechanisms ( 17 ) and phenomenological proximity (particularly insofar as social interaction deficits, communication difficulties and restricted interests are concerned) ( 18 ), fuelling an ongoing debate on whether the two conditions lie on the same neurodevelopmental and phenotypic continuum ( 17 – 19 ). The available literature has reached contradictory conclusions on this issue, with the few existing meta-analyses allowing for indirect comparisons at best.…”

Face perception predicts affective theory of mind in autism spectrum disorder but not schizophrenia or typical development.

“…Social cognition, the processes of perception and interpretation of social information, predicts individual differences in social dysfunction in both SCZ and ASD (Brothers, 2002). Shared difficulties with social cognition in ASD and SCZ are central to the ongoing debate about whether the disorders lie on the same phenotypic continuum (Anomitri & Lazaratou, 2017; Martinez et al, 2017). However, the few comparative studies of social cognition in ASD and SCZ have produced mixed results (for a systematic review and meta-analysis, see Fernandes et al, 2018).…”