Change in Receptive Vocabulary from Childhood to Adulthood: Associated Mental Health, Education and Employment Outcomes

Background: Population-based studies have found that early language delays are associated with poorer long-term outcomes in adolescence and adulthood. Few studies have explored the influence of change in language ability over time on adult outcomes. Aim: To examine the educational, vocational and mental health outcomes for adults accounting for different vocabulary developmental profiles over a 16-year period. Methods & Procedures: A total of 1914 participants of the Mater-University of Queensland Study of Pregnancy (MUSP) were categorized into four groups based on their vocabulary skills at 5 and 21 years: (1) persistently good (n = 1679), (2) persistently poor (n = 33), (3) improved (n = 160), and (4) deteriorated (n = 42). The associations between vocabulary group and educational, vocational, and mental health outcomes at 21 years were investigated. Outcomes & Results: Adults with deteriorated and persistently poor vocabulary skills were less likely to have completed secondary school; with the improved, deteriorated and persistently poor groups being less likely to be engaged in education, employment or training at the 21-year follow-up, compared with the persistently good group. Adults with deteriorated performance were at an increased risk of affective disorders, as well as substance and alcohol abuse/misuse. Conclusions & Implications: These findings provide evidence that impaired vocabulary skills in adulthood, regardless of whether the deficit was acquired early or later, are associated with adverse outcomes. Clinicians and educators need to be aware of these adversities and ensure they are supporting children and adolescents in whom language difficulties exist or emerge so as to prevent poor long-term outcomes from occurring.