• Left- and mixed-handedness are more common in individuals with early-onset neurodevelopmental disorders featuring linguistic symptoms.
• Dyslexia, autism, and schizophrenia show a statistically significant increase in left- and mixed-handedness compared to the general population.
• The link between handedness and these disorders likely stems from overlapping processes during early brain development.

An international research team conducted a meta-analysis investigating the relationship between handedness and various mental and neurodevelopmental disorders. The study, published in Psychological Bulletin on May 2, 2025, revealed a significant correlation between left- and mixed-handedness and disorders that manifest early in life and involve linguistic symptoms, such as dyslexia, autism, and schizophrenia. The researchers propose that shared developmental processes in the brain during early stages may underlie this association.

• What: A meta-analysis demonstrates a link between left/mixed-handedness and early-onset neurodevelopmental disorders, particularly those involving language.
• Who: The research team consists of members from Ruhr University Bochum, Hamburg, Nijmegen, and Athens, led by Dr. Julian Packheiser and Professor Sebastian Ocklenburg.
• When: The findings were published in the journal Psychological Bulletin on May 2, 2025.
• Where: The research was conducted by an international team spanning Bochum, Hamburg, Nijmegen, and Athens.

The meta-analysis provides compelling evidence for the association between handedness and specific neurodevelopmental disorders. The finding that early-onset disorders with linguistic symptoms show a stronger correlation with left/mixed-handedness suggests that disruptions during early brain development may affect both language lateralization and handedness. This transdiagnostic perspective offers a valuable framework for understanding the complex interplay between developmental processes and neurological conditions. Further research is needed to elucidate the underlying mechanisms and potential clinical implications.

We suspected that left- and mixed- handedness could be associated with disorders whose symptoms are related to language.

Both hypotheses have been confirmed.

The meta-analysis strengthens the understanding of the relationship between handedness and neurodevelopmental disorders. By highlighting the significance of early onset and linguistic symptoms, the research provides a valuable perspective for future investigations into the neurodevelopmental origins of these conditions. While the study establishes a correlation, further research is necessary to fully understand the causal mechanisms and potential interventions.