Left is best?

Does it matter if you write with your left hand, your right or use both interchangeably? Not really if your handwriting is legible, but it is clear is that people who are right handed, left handed or ambidextrous seem to have certain traits. ‘We can certainly find links between a range of conditions and left-handedness for example, but it’s harder to say for sure why this happens,’ says Dr Peter Congdon, a consultant educational psychologist who founded the Gifted Children’s’ Information Centre in Solihull which has a department for helping left-handed children and adults.

Left-handers may be more successful but they will also be clumsier than the right-handed peers, according to research.

A worrying Canadian study published in 1991 did suggest that left-handed people were more likely to die at a younger age. Researchers in Dakota in the US confirmed this study in 2001 when they found that right-handers lived nearly four years longer than left-handers. But ambidextrous people outlived everyone, including the right-handers, by more than two years. However, good news for left-handers is that other studies using better methods have found only slight differences in life expectancy, because there is higher risk of accidental death in left-handers who are disadvantaged because they need to operate in a ‘right friendly’ world.

Allergies -long been associated with left-handedness – are unlikely to be more prevalent if you pick up your fork with your left hand. Although various studies in the past have shown that left-handed people are more likely to suffer from allergic problems, a large-scale meta-analysis failed to find convincing evidence that this was true.

And you are much less like to suffer from ulcers and arthritis, according to a very large 2001 study at UCL in the UK and the US. For every 100 right-handers with an ulcer or arthritis, only 92 left-handers will have the conditions. Over a million people took part in the study which looked for prevalence of a wide range of illnesses and conditions. They were asked to fill out a detailed questionnaire about the health and whether they were right or left handed. The authors said that the mechanism for the ‘very significant’ effect was unclear and seemed unlikely to be due to immune factors. Further investigation is needed to replicate these findings.

While left-handedness and ambidexterity are associated with some physical challenges, they are also linked to mental health issues.

Early studies on right-handed War veterans found those who were less strongly right handed were more likely to suffer from PTSD. Dr Carolyn Choudhary, who carried out research in a civilian population found that left-handers were more likely than right-handers to have PTSD, and believes that this may be linked to the fact that the right side of the brain (dominant in left-handers) may also be in control of the fear response. ‘PTSD is a disorder which is mainly physiologically driven by the fear response. There seems to be an association between left-handed people and PTSD, left handed but we don’t yet know exactly what the links are.’

Lefties are not any more likely to become alcoholics than right handed people, according to a large study of 25,000 people from 12 countries which was published in the British Journal of Health Psychology, although they did tend to drink more.

Attention Deficit Hyperactivity Disorder and other disorders linked to brain development like dyslexia and dyspraxia, are more left-handed people, according to a 2010 study published in Pediatrics. However, Dr Peter Congdon is not convinced, suggesting that ADHD is caused by many things and ‘nothing is black and white.’ True ADHD is not found in greater numbers of left handed children, even though attention deficit may be prevalent because of frustration experienced by many left handed children in the classroom. Failures to teach proper ‘left handed’ writing in schools sows the seeds for many future problems, he says. ‘If left handed children are taught to read, write and spell at an early age, using the correct techniques, they do as well as right handed children when they reach adolescence. Unfortunately, many teachers do not how to teach left-handed children.’