Handedness as a neurodevelopmental marker in schizophrenia: Results from the FACE-SZ cohort

Abstract

Objectives

High rates of non-right-handedness (NRH) including mixed-handedness have been reported in neurodevelopmental disorders. In schizophrenia (SZ), atypical handedness has been inconsistently related to impaired features. We aimed to determine whether SZ subjects with NRH and mixed-handedness had poorer clinical and cognitive outcomes compared to their counterparts.

Methods

667 participants were tested with a battery of neuropsychological tests, and assessed for laterality using the Edinburg Handedness Inventory. Clinical symptomatology was assessed. Learning disorders and obstetrical complications were recorded. Biological parameters were explored.

Results

The prevalence of NRH and mixed-handedness was high (respectively, 42.4% and 34.1%). In the multivariable analyses, NRH was associated with cannabis use disorder (p = 0.045). Mixed-handedness was associated with positive symptoms (p = 0.041), current depressive disorder (p = 0.005)), current cannabis use (p = 0.024) and less akathisia (p = 0.019). A history of learning disorder was associated with NRH. No association was found with cognition, trauma history, obstetrical complications, psychotic symptoms, peripheral inflammation.

Conclusions

Non-right and mixed-handedness are very high in patients with SZ, possibly reflecting a neurodevelopmental origin. NRH is associated with learning disorders and cannabis use. Mixed-handedness is associated with positive symptoms, current depressive disorder, cannabis use and less akathisia. However, this study did not confirm greater cognitive impairment in these patients.

Keywords:

• Schizophrenia
• psychosis
• cognition
• neurodevelopment
• handedness

Acknowledgements

Authors express thanks to the nurses, and to the patients who were included in the present study. Authors thank Hakim Laouamri and his team for the development of the FACE-SZ computer interface, data management, quality control and regulatory aspects.

Author contributions

All authors acquired the data, which J. Mallet, O. Godin, G. Fond, Y. Le Strat and C. Dubertret analysed. O. Godin completed the statistical analyses. J. Mallet wrote the article, which all authors reviewed. All authors approved the final version to be published.

Disclosure statement

J. Mallet is a member of Labex BioPsy.

Additional information

Funding

This work was funded by AP-HP (Assistance Publique des Hôpitaux de Paris), Fondation FondaMental (RTRS Santé Mentale), the ‘Investissements d’Avenir’ programs managed by the Agence Nationale de Recherche (ANR), France under references [ANR-11-IDEX-0004-02] and [ANR-10-COHO-10-01], and by INSERM (Institut National de la Santé et de la Recherche Médicale). The funding sources had no role in this study.