LAUSR

Abstract Background Early childhood development is considered to be the most critical developmental phase throughout the lifespan. Cognitive and motor dysfunction are hallmark features found along the psychosis spectrum and have also been shown in young people who report subclinical psychotic experiences (PE). Whether such deficits can be detected in infancy is not yet known. The aim of the present research was to examine early childhood developmental skills and their association with PE in childhood and adolescence. Methods Data was taken from the Western Australia Pregnancy Cohort (Raine) Study, a pregnancy cohort study in which 2,868 infants were enrolled. Early childhood development was measured at age 1, 2 and 3 using the Infant Monitoring Questionnaire (IMQ; now the Ages and Stages questionnaire. Outcome of interest: PE was measured at age 10 via parent-report, and at age 14 and 17 via self-report by the participants using the 2 items (‘hearing things’ and ‘seeing things’) from the Child Behaviour Checklist (CBCL)/Youth Self-Report (YSR) thought problems subscale. The PE group included any participant who endorsed either or both of the items at any of the 3 time-points. The PE group was further subdivided into those who endorsed transient PE (one time-point) or recurring PE (2 or more time-points). Random effects logistic regression models were performed to investigate the relationship between early childhood development and later risk. Developmental time specific investigations (at age 1, 2 and 3 years of age separately) were also conducted using logistic regressions. Cumulative risk based on category specific deficits at age 3 was also calculated. This analysis was also applied to compare the PE group vs. controls, the transient PE group vs. controls and the recurring PE group vs. controls. Results In the first 3 years of life, lower scores in communication (adjusted OR = 1.32, 95% CI = 1.01–1.72, p = 0.05) and adaptive (problem-solving) (adjusted OR = 1.26, 95% CI = 1.01–1.59, p = 0.048) skills were found to be predictive of PE in childhood and/or adolescence. For the age specific analysis, adaptive skill deficits specifically at 1 year of age predicted PE (adjusted OR = 1.18, 95% CI = 1.03–1.35, p = 0.017), while at 2 years of age, deficits in communication (adjusted OR = 1.35, 95% CI = 1.18–1.54, p<0.001) and adaptive skills (adjusted OR = 1.25, 95% CI = 1.08–1.45, p<0.005) predicted PE. Importantly, at 3 years of age, deficits in any of the 5 categories (communication, gross motor, fine motor, adaptive and personal social) were predictive of PE. Deficits (lowest 10th percentile) in 1–2 categories at 3 years of age led to an almost a 2-fold increase risk of having a PE (adjusted OR = 1.94, 95% CI = 1.38–2.71, p < 0.001), while deficits in 3–5 categories led to a 3-fold increased risk of having a PE (adjusted OR = 3.02, 95% CI = 1.65–5.50, p = <0.001). When subdividing PE into those with transient and recurring PE, different patterns emerged, in which motor deficits in the first 3 years of life were more associated with the recurring PE group. Discussion The present research suggests that lower scores in early childhood developmental skills in the first 3 years of life are strongly associated with childhood and adolescent PE. Results showed that deviances in communication and problem-solving abilities during the first 3 years of life are particularly associated. At age 3 specifically, deficits in all domains of development are predictive of PE, and the greater the number of category deficits, the greater the risk. Differing patterns of development emerge for the transient PE and recurring PE groups. The findings enlighten the understanding of the neurodevelopmental origins of early onset PE for a proportion of individuals.