Oral language acquisition difficulties in patients with early-onset schizophrenia or bipolar disorder

Schizophrenia and bipolar disorder are psychiatric conditions increasingly recognized as involving an underlying neurodevelopmental dimension, particularly in early-onset forms. Among neurodevelopmental disorders, language disorders occupy a central place; yet, their specific association with schizophrenia and bipolar disorder remains insufficiently explored. This retrospective case-control study compared the prevalence of oral language acquisition difficulties among 92 hospitalized patients diagnosed with early-onset schizophrenia (n=52) or early-onset bipolar disorder (n=40). Clinical and developmental information was extracted from medical records, with particular attention to diagnoses of oral language disorder (characterized using standardized speech-language assessments) and Wechsler Verbal Comprehension Index scores. A non-significant trend towards a higher prevalence of oral language disorder was found in the early-onset schizophrenia group (38.5%) compared with early-onset bipolar disorder (22.5%). However, when only diagnoses established before the onset of psychiatric symptoms were considered, the difference became significant (32.7% vs. 10.0%; P=0.02), suggesting that language disorders may be more severe in early-onset schizophrenia and therefore more readily identifiable earlier in development. The early-onset schizophrenia group also exhibited significantly lower Verbal Comprehension Index scores and more childhood school difficulties. These findings support the hypothesis of a greater neurodevelopmental burden in early-onset schizophrenia, particularly regarding language development, and underscore the importance of early detection of oral language disorders to improve support and functional outcomes.