Schizophrenia is more common among young, illiterate individuals, according to a population-based study in China.
In fact, illiterate people less than 40 years of age are more than twice as likely to develop schizophrenia as their literate peers, found Xiaoying Zheng of Peking University, China and team.
Schizophrenia is a mental disorder characterized by the breakdown of thought processes along with poor emotional responsiveness. The most common symptoms include auditory hallucinations, paranoid or bizarre delusions, and disorganized speech and thinking.
“Both social selection and social cause processes may have operated in the association,” said the authors.
The findings stem from data on 1,909,205 individuals, aged 18 years or older, from the Second China National Sample Survey on Disability in 2006, of whom 7628 reported a diagnosis of schizophrenia.
Overall, 15.3% of the study population was illiterate, as ascertained through face-to-face interviews.
The prevalence of schizophrenia among illiterate individuals aged was 1.64 percent in the 18-29 age group, 1.51% (ages 30-39), 1.07% (ages 40-49), 0.88% (ages 50-59), and 0.50% (60 years or older). Corresponding rates for literate individuals were 0.22%, 0.37%, 0.39%, 0.42%, and 0.29%.
After accounting for gender, age, marital status, location of residence, and household income, the researchers discovered that illiterate people were far more likely to develop schizophrenia than literate individuals, with a stronger association among those under 40 than among older individuals.
Researchers conducted further analysis that controlled for environment and genetic risk in more than 26,000 sibling groups under the age of 40. They found that illiterate siblings were 2.8 times more likely to develop schizophrenia than literate siblings from the same family.
“The current study found a strong association between illiteracy and schizophrenia among Chinese people less than 40 years old,” conclude Zheng and team in Social Psychiatry and Psychiatric Epidemiology.
“Future studies on the association between social environment and risk of schizophrenia as well as mechanisms underlying the association are necessary,” they said.