Some reports argued that birth complications can increase the occurrence of left handedness and thereby the risk for mental disorders. Is that true? Scientists from Bochum, Hamburg, and Göttingen joined forces and tested 598 healthy participants in depth for functional asymmetries, birth events, and clinical conditions. It turned out that early life factors had no substantial effects on functional asymmetries of hand, foot, and language. Also, the link to clinical conditions was weak. If at all, an overall reduction or an absence of asymmetries, as in mixed-handed people, seemed to be of (limited) clinical relevance.

Pfeifer, L. S., Schmitz, J., Schwalvenberg, M., Güntürkün, O., Ocklenburg, S., Handedness, early life factors and mental health: A deep phenotyping approach, Sci. Rep., 2023, 13:15348.