Paper Short Abstract

This paper uses the case of handedness in neurodevelopmental disorders to illustrate how databases from existing meta-analyses can be leveraged for second-order meta-analyses. This involves updating and reanalyzing previously published meta-analyses in identical analysis pipelines.

Paper Abstract

This paper explores handedness in neurodevelopmental disorders to demonstrate how databases from existing systematic reviews and meta-analyses can be utilized for second-order meta-analyses. To this end, we reviewed and updated previously published meta-analyses concerning hand preference in mental and neurodevelopmental disorders, aiming to identify overarching patterns and estimate the influence of potential moderators independent of diagnosis. A total of 402 datasets encompassing 202,434 individuals were analyzed. Our findings indicate that atypical hand preference, including non-right, left, and mixed preferences, is significantly more prevalent in clinical samples compared to controls, with odds ratios (OR) for non-right of OR = 1.46, 95% CI = [1.35;1.59]; for left of OR = 1.34,95%, CI = [1.22;1.48], and for mixed of OR = 1.63, 95% CI = [1.38;1.93]. Notably, disorders such as schizophrenia exhibit particularly high rates of atypical hand preference (non-right OR: 1.50, 95% CI = [1.32;1.70]; left OR: 1.37, 95% CI = [1.17;1.61]; mixed OR: 1.70, 95% CI = [1.19;2.44]). Moderator analyses revealed that neurodevelopmental conditions, non-neurodevelopmental conditions with early onset, and conditions with language-related symptoms are all linked to higher rates of atypical hand preference. This research indicates that the relationship between handedness and psychopathology is best understood from a transdiagnostic, developmental, and symptom-focused perspective. From a methodological standpoint, our study underscores the potential of second-order meta-analysis to enhance trust in scientific findings.