LEFT-HANDEDNESS AND ASSOCIATED PSYCHOSOCIAL CORRELATES AMONGST SECONDARY SCHOOL STUDENTS IN IBADAN, NIGERIA

Abstract

Background: About ten percent of the world’s population is left-handed (LH), but in many parts of the world, especially in low and middle-income countries such as Nigeria, the use of the left hand is culturally frowned upon and actively discouraged or suppressed. Parents, community elders and teachers often exert significant pressure including punishments to actively dissuade children who are left-handed from using it freely. Ultimately, a significant majority in these cultural settings are converted into using their right hands. However, studies from other parts of the world, have indicated that this forced conversion from left-handedness into right-handedness is often associated with mental health problems especially in children and adolescents. Yet there is a paucity of studies evaluating this association in Nigeria. Aim: To assess the prevalence of psychiatric morbidity and its correlates among LH students compared with right-handed (RH) students.

Methodology: A total of 875 students were screened with the Edinburgh Handedness Inventory. Subsequently, 53 LH students and 53 matched RH students were interviewed with a 3-item questionnaire on sociocultural pressure and the Schedule for Affective Disorder and Schizophrenia for School-Age Children (K-SADS) for the former (LH students only); while only the K-SADS was utilized for the latter group (RH students).

Result: The prevalence of left-handedness among the screened students was 6.05%. The prevalence of any psychiatric disorder was 37.7% for LH as compared to 10% for the RH comparison group. Most LH (73.6%) students reported being persistently discouraged from using the left hand for common tasks. LH students with experience of sociocultural pressures against the use of their dominant left hand were more likely to have a psychiatric diagnosis than those who do not experience such pressures (46.2% v. 14.3% X2=4.453, OR=5.155, p=0.035). Conclusions: Left-handed students had higher rates of psychiatric disorders as compared to RH students, and LH students who reported being pressured had even more elevated risks. Public awareness campaigns should be directed towards educating caregivers, teachers and parents about handedness as a biologically mediated process, as well as the risks of pressurising children to change their handedness (sinistrality).