Evidence that infant and early childhood developmental impairments are associated with hallucinatory experiences: Results from a large, population-based cohort study

Background: Cognitive and motor dysfunction are hallmark features of the psychosis continuum, and have been detected during late childhood and adolescence in youth who report psychotic experiences (PE). However, previous investigations have not explored infancy and early childhood development. It remains unclear whether such deficits emerge much earlier in life, and whether they are associated with psychotic, specifically hallucinatory, experiences (HE).

Methods: This study included data from Gen2 participants of The Raine Study (n = 1101), a population-based longitudinal cohort study in Western Australia. Five areas of childhood development comprising: communication; fine motor; gross motor; adaptive (problem-solving); and personal-social skills, were assessed serially at ages 1, 2 and 3 years. Information on HE, depression and anxiety at ages 10, 14 and 17 years was obtained. HE were further subdivided into those with transient or recurrent experiences. Mixed effects logistic regression models and cumulative risk analyses based on multiple domain delays were performed.

Results: Early poorer development in multiple areas was noted from ages 1, 2 and 3 years among youth who reported HE. Early developmental delays significantly increased the risk for later HE. This association was particularly marked in the recurrent HE group, with over 40% having early developmental delays in multiple domains. There was no significant association between early childhood development and later anxiety/depression apart from lower gross motor scores at age 3.

Conclusions: The findings suggest that early pan-developmental deficits are associated with later HE, with the effect strongest for young people who report recurrent HE throughout childhood and adolescence.