IQ trajectories in autistic children through preadolescence

Area of Science:

• Neuroscience
• Developmental Psychology
• Child Psychiatry

Background:

• Longitudinal study of intellectual development in autistic individuals.
• Followed 373 autistic children from early childhood to preadolescence.
• Utilized data from the Autism Phenome Project cohort.

Purpose of the Study:

• Identify distinct intellectual quotient (IQ) trajectory subgroups in autistic youth.
• Analyze developmental courses and predictors of trajectory membership.
• Understand the long-term intellectual development patterns in autism.

Main Methods:

• Multivariate latent class growth analysis to identify IQ trajectory subgroups.
• Linear mixed effects models for group differences and developmental courses.
• Multinomial logistic regression to assess predictors of trajectory membership.

Main Results:

• Three distinct IQ trajectories identified: persistent intellectual disability (45%), substantial IQ increases (39%), and persistently high IQ (16%).
• No significant differences in autism severity or communication scores by preadolescence.
• Early communication gains and reduced externalizing behaviors predicted better IQ trajectories.

Conclusions:

• Autistic youth exhibit stable IQ developmental trajectories from early childhood to preadolescence.
• Prognostic factors for trajectory membership may inform targeted interventions.
• Focus on improving adaptive communication and managing externalizing symptoms is crucial.