Left-handers more likely to develop psychotic disorders, says study
Article date: 5 November 2013
New research has suggested that lefties are more likely to develop psychotic disorders such as schizophrenia than their right-handed peers.
While other mental disorders like anxiety have been linked to being left-handed, the findings from Yale University reveal that individuals with mental illnesses of a psychotic nature are more likely to be left-handed than people with mood issues such as depression or bipolar tendencies.
Published in the journal SAGE Open, the findings revealed that 11 per cent of individuals in the US with mood disorders were left-handed, compared to a considerably more significant 40 per cent of those with schizophrenia or schizoaffective disorder.
Yale researcher Jadon Webb described the discrepancy as "striking", commenting: "In general, people with psychosis are those who have lost touch with reality in some way, through hallucinations, delusions, or false beliefs, and it is notable that this symptom constellation seems to correlate with being left-handed."
He added that isolating trends such as this might help scientists and medical professionals to identify and make distinctions between different mental disorders - and the risk factors for certain individuals developing them - earlier and thereby improve how they are treated.
The findings follow research - published in PLOS Genetics - by scientists at the Universities of Oxford, St Andrews, Bristol and the Max Plank Institute in Nijmegen, The Netherlands revealing that genes could be linked to the determination of whether an individual is right or left-handed.
"Genes are involved in the biological process through which an early embryo moves on from being a round ball of cells and becomes a growing organism with an established left and right side," explained study author William Brandler, a PhD student in the MRC Functional Genomics Unit at Oxford University.
Official figures suggest that around 90 per cent of human beings are right-handed - a trend which is largely unexplained.
Now, it is believed the gene PCSK6 - implicated in establishing the left and right in a growing embryo - may be heavily involved in determining this outcome.