report in which he noted that among 47 inpatients on an alcoholism ward, 7 were left-handed - more than you'd expect based on the approximate 10-per cent prevalence of left-handedness in the general population. Bakan described his observation as 'incidental' but according to Kevin Denny, the idea of an alcoholism-handedness link has proven sticky, with some commentators suggesting the stress of being left-handed in a right-handed world is to blame.
Several studies through the years have attempted to replicate the left-handed-alcoholism link but most have relied on small samples and any way the results have been inconsistent. Denny's contribution is an examination of data from the SHARE survey involving over 25,000 people from 12 countries. Left-handers aren't more prone to risky drinking, Denny finds, but on average they do drink more often.
Denny made his finding after categorising survey participants based on their self-reports as either heavy drinkers (those who drink 'almost everyday' or '5 or 6 days a week') or light drinkers (less than once a month or not at all for last six months). There was no evidence that handedness was related to excessive drinking, but left-handers were significantly less likely to be in the light drinker category than right-handers, suggesting that, on average, a left-hander is more likely than a right-hander to drink at moderate levels.
'There is no evidence that handedness predicts risky drinking,' Denny wrote. 'Hence, the results do not support the idea that excess drinking may be a consequence either of atypical lateralisation of the brain or due to the social stresses that arise from left-handers being a minority group.'
Denny acknowledges his study has limitations - all participants in the SHARE survey are over 50, so it's possible his findings don't generalise to younger people. Related to this, it's possible that some heavy-drinking left-handers died before the age of 50, although their numbers are likely to be small. Another potential shortcoming is that some participants categorised as non-drinkers may have been problem-drinkers in recovery.
Denny, K. (2010). Handedness and drinking behaviour. British Journal of Health Psychology DOI: 10.1348/135910710X515705
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.