Abstract
Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder marked by persistent deficits in social communication and interaction, alongside restricted, repetitive patterns of behaviors (RRB), interests, or activities. It often co-occurs with various neuropsychiatric disorders, though their frequency varies widely due to unclear boundaries between the core features of ASD and common comorbidities. Catatonia, increasingly noted in neurodevelopmental conditions like ASD, shares striking similarities with ASD in symptomatology, brain mechanisms, and treatment responses, prompting the question of whether it is a core feature of ASD or a distinct condition. This paper delved into this overlap, exploring the relationship between catatonia and ASD through a narrative review of peer-reviewed literature from 1943 to 2024, sourced from PubMed and psychiatric journals. Focusing on ASD diagnostic evolution, symptom overlap with catatonia, and shared neurobiological and therapeutic characteristics, we used thematic analysis to synthesize findings into key areas such as historical nosology, phenomenological overlap, neurobiological parallels, and treatment response. The evidence revealed weak support for separating catatonia from overlapping RRB features of ASD, suggesting that some RRB might align more with comorbid catatonia than intrinsic ASD traits. However, this idea needs further validation through rigorous clinical trials. Clarifying this relationship could refine diagnostic approaches and open doors to targeted treatments, potentially improving outcomes for those affected.