Cranial fluctuating asymmetry and schizophrenia in a contemporary Danish population

Abstract

Post-mortem Computed Tomography (PMCT) scans in forensic medicine not only assist with case work but is also a useful data source for other imaging-based research, e.g. morphological studies on bones. PMCT 3D data can be combined with diagnostic information and help to elucidate how disease manifests in the body. For example, the skeleton can be influenced by developmental instability, which may result in a morphological change called fluctuating asymmetry (FA). Developmental instability also influences the risk of developing schizophrenia, which means that individuals with higher levels of developmental instability, and by extension FA, might have a higher risk of developing the disorder. This connection has been investigated in soft tissues but has not yet been investigated in bones. We used PMCT 3D models from a forensic cohort to compare levels of cranial FA between a group of individuals with diagnosed schizophrenia and a control group. Our sample included 48 individuals with diagnosed schizophrenia and 58 controls. We collected 27 landmarks from our 3D models. Levels of fluctuating asymmetry were analysed using Procrustes ANOVA, and the two groups were compared using t-test and Wilcoxon rank sum test. Age and sex were tested as factors using Pearson correlation and two-way ANOVA. We found that there was no statistically significant difference in levels of cranial FA between the schizophrenic group and the control group, and that neither age nor sex was a factor. Our results confirm earlier studies that suggest that the multifactorial aetiology of FA and schizophrenia is difficult to capture comprehensively.