Language and mathematical problems as precursors of psychotic-like experiences and juvenile mania symptoms

Background. Psychotic-like experiences (PLEs) and juvenile mania in adolescence index risk for severe psychopathology in adulthood. The importance of childhood problems with communication, reading, speech and mathematics for the development of PLEs and juvenile mania is not well understood. Method. Through the Child and Adolescent Twin Study in Sweden, we identified 5812 children. The parents were interviewed about their children's development at age 9 or 12 years. At age 15 or 18 years, children and parents completed questionnaires targeting current PLEs and juvenile mania symptoms. Logistic regressions were used to assess associations between problems with communication, reading, speech and mathematics and PLEs/juvenile mania symptoms. To evaluate the relative importance of genes and environment in these associations, we used bivariate twin analyses based on structural equation models. Results. Children with parent-endorsed childhood problems with communication, reading and mathematics had an increased risk of developing auditory hallucinations and parental-reported juvenile mania symptoms in adolescence. The most consistent finding was that children with childhood problems with communication, reading and mathematics had an increased risk of developing auditory hallucinations [for example, the risk for self-reported auditory hallucinations at age 15 was increased by 96% for children with communication problems: OR (odds ratio) 1.96, 95% confidence interval (CI) 1.33-2.88]. The twin analyses showed that genetic effects accounted for the increased risk of PLEs and juvenile mania symptoms among children with communication problems. Conclusions. Childhood problems with communication, reading and mathematics predict PLEs and juvenile mania symptoms in adolescence. Similar to the case for schizophrenia and bipolar disorder, PLEs and juvenile mania may share genetic aetiological factors.