Non-Right-Handedness in Schizophrenia Linked to Cannabis Use Disorder

In a large schizophrenia cohort, non-right-handedness was associated with cannabis use disorder, while mixed-handedness was linked to current cannabis use, positive symptoms, and depression.

RTHC-04033Cross SectionalModerate Evidence2022RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Moderate Evidence
Sample
N=667

What This Study Found

Among 667 schizophrenia patients, 42.4% were non-right-handed and 34.1% mixed-handed. Non-right-handedness was associated with cannabis use disorder (P=0.045) and learning disorders. Mixed-handedness was associated with positive symptoms (P=0.041), current depression (P=0.005), current cannabis use (P=0.024), and less akathisia (P=0.019).

Key Numbers

667 participants; 42.4% non-right-handed; 34.1% mixed-handed; NRH associated with CUD (P=0.045); mixed-handedness with current cannabis use (P=0.024)

How They Did This

Cross-sectional study of 667 participants from the FACE-SZ cohort assessed with the Edinburgh Handedness Inventory, neuropsychological testing, and clinical symptom measures.

Why This Research Matters

Non-right-handedness is considered a marker of atypical neurodevelopment. Its association with cannabis use disorder in schizophrenia suggests shared developmental vulnerabilities may underlie both traits.

The Bigger Picture

The very high rate of atypical handedness in this schizophrenia cohort (42.4% vs ~10% in the general population) reflects neurodevelopmental disruption that may also predispose to substance use.

What This Study Doesn't Tell Us

Cross-sectional design cannot determine direction of associations. Handedness was self-reported. Cannabis use assessment relied on clinical records.

Questions This Raises

  • ?Does the shared neurodevelopmental basis for non-right-handedness and cannabis use disorder suggest a common genetic pathway?
  • ?Would early identification of atypical handedness in psychosis patients flag higher substance use risk?

Trust & Context

Key Stat:
42.4% non-right-handed in schizophrenia cohort
Evidence Grade:
Large cohort with validated assessments, but cross-sectional design limits causal interpretation.
Study Age:
Published in 2022
Original Title:
Handedness as a neurodevelopmental marker in schizophrenia: Results from the FACE-SZ cohort.
Published In:
The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry, 23(7), 525-536 (2022)
Database ID:
RTHC-04033

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

Why is handedness relevant to schizophrenia and cannabis?

Non-right-handedness reflects atypical brain development and is far more common in schizophrenia (42.4% in this study vs ~10% in the general population). Its association with cannabis use disorder suggests both may share developmental roots.

Did mixed-handedness affect symptoms?

Yes. Mixed-handed patients had more positive symptoms, higher rates of current depression and cannabis use, but less akathisia (medication-induced restlessness).

Read More on RethinkTHC

Cite This Study

RTHC-04033·https://rethinkthc.com/research/RTHC-04033

APA

Mallet, Jasmina; Godin, Ophélia; Le Strat, Yann; Mazer, Nicolas; Berna, Fabrice; Boyer, Laurent; Capdevielle, Delphine; Clauss, Julie; Chéreau, Isabelle; D'Amato, Thierry; Dubreucq, Julien; Leigner, Sylvain; Llorca, Pierre-Michel; Misdrahi, David; Passerieux, Christine; Rey, Romain; Pignon, Baptiste; Urbach, Mathieu; Schürhoff, Franck; Fond, Guillaume; Dubertret, Caroline. (2022). Handedness as a neurodevelopmental marker in schizophrenia: Results from the FACE-SZ cohort.. The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry, 23(7), 525-536. https://doi.org/10.1080/15622975.2021.2013094

MLA

Mallet, Jasmina, et al. "Handedness as a neurodevelopmental marker in schizophrenia: Results from the FACE-SZ cohort.." The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry, 2022. https://doi.org/10.1080/15622975.2021.2013094

RethinkTHC

RethinkTHC Research Database. "Handedness as a neurodevelopmental marker in schizophrenia: ..." RTHC-04033. Retrieved from https://rethinkthc.com/research/mallet-2022-handedness-as-a-neurodevelopmental

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.