The Concept of Autism in Autism Spectrum Disorder and Schizophrenia Spectrum Disorder: Historical Divergence and Phenomenological Rapprochement

This study aims to trace the historical origins and conceptual divergence of "autism" as employed in autism spectrum disorder (ASD) and schizophrenia spectrum disorder (SSD), and to examine their recent rapprochement through the lens of phenomenological psychopathology. A narrative review was conducted to analyze primary historical sources, including works by Bleuler, Kanner, and their predecessors, along with contemporary literature on neurodevelopmental perspectives, social cognition, and phenomenological psychopathology. The analysis focused on comparing the structures of self-experience between patients with ASD and those with SSD using frameworks such as ipseity disturbance and anomalous self-experience. Bleuler's "Autismus" (1911) denoted active withdrawal from reality and construction of an inner fantasy world in schizophrenia, whereas Kanner's "infantile autism" (1943) described innate deficits in forming affective bonds. Despite strict diagnostic separation since DSM-III, recent research reveals shared genetic pathways, social cognitive impairments, and clinical presentations. Phenomenological analysis revealed that while both conditions share common predicaments in being-in-the-world, they manifest qualitatively distinct patterns of self-disorder. Patients with SSD exhibit ipseity disturbance characterized by instability of the minimal self, diminished self-affection, and hyperreflexivity, whereas patients with ASD generally show preserved minimal self but deficient intersubjective attunement. Social withdrawal in SSD represents a defensive retreat against ontological anxiety and self-dissolution, whereas in ASD it reflects involuntary isolation arising from impaired intuitive connections with others. ASD and SSD share common predicaments in being-in-the-world, yet manifest qualitatively distinct forms of self-disorder. This phenomenological framework offers a promising transdiagnostic approach for clarifying the relationship between these two conditions and understanding the essence of "autism."