The Triad of Childhood-Onset Schizophrenia, Autism Spectrum Disorder, and Catatonia: A Case Report.

Childhood-onset schizophrenia (COS) is a rare and severe form of schizophrenia with an estimated prevalence of 1/10,000. Schizophrenia and Autism spectrum disorder (ASD) have shared phenotypic features and shared genetic etiology. There is growing research surrounding the co-occurrence of psychomotor syndromes like catatonia with neurodevelopmental disorders like ASD or psychiatric disorders like schizophrenia. In 2013, Shorter and Wachtel described a phenomenon of the 'Iron Triangle' where COS, ASD, and catatonia often co-occur. The Iron Triangle theory is based on observation of historical case literature, which showed that all three diagnoses in the Iron Triangle were routinely assigned to children and adolescents. The pattern of this "Iron Triangle" suggests there may be a single underlying pathology resulting in a unique mixed form of catatonia, autism, and psychosis. We describe the case of a boy with sequential development of COS, ASD, and catatonia who also has syndromic facial and musculoskeletal features. This case highlights overlapping diagnostic features of these three disorders and can help us better understand how "hidden" features of catatonia may occur in patients with COS or ASD but go unrecognized, because they are grouped as features under autism/schizophrenia rather than a distinct diagnosis of catatonia. Further study is warranted to elucidate if this phenotypic pattern constitutes a new single diagnosis that is not well understood, an endophenotype of schizophrenia, or if this is the result of phenomenological overlap between catatonia, ASD, and COS.