Disentangling the associations between autistic-like and internalizing traits: a community based twin study

Area of Science:

• Child Psychology
• Neurodevelopmental Disorders
• Psychiatric Comorbidity

Background:

• Internalizing difficulties are common in children with autism spectrum disorder (ASD).
• The specific links and causes of this comorbidity are not well understood.
• Identifying associations between autistic traits and internalizing symptoms is crucial for diagnosis and treatment.

Purpose of the Study:

• To investigate the phenotypic and etiological associations between specific autistic-like traits and internalizing traits in a population-based sample.
• To determine which autistic-like traits (social, communication, repetitive behaviors) are most strongly associated with internalizing difficulties (social anxiety, fears, generalized anxiety, negative affect).
• To explore the genetic and environmental underpinnings of these associations.

Main Methods:

• Analysis of parent-reported data from 7,311 twin pairs at ages 7–8 years.
• Utilized structural equation modeling to examine phenotypic and etiological overlap.
• Assessed three autistic-like traits and four internalizing trait subtypes.

Main Results:

• Modest phenotypic associations (rph = 0.00–0.36) were observed between autistic-like traits and internalizing difficulties.
• Autistic-like communication impairments and repetitive/restricted behaviors showed the strongest phenotypic and genetic correlations with generalized anxiety and negative affect.
• Autistic-like social difficulties demonstrated minimal overlap with internalizing behaviors.

Conclusions:

• Specific autistic-like traits have distinct associations with internalizing difficulties.
• Communication and repetitive behaviors in ASD are phenotypically and genetically linked to generalized anxiety and negative affect.
• Findings may inform the conceptualization and diagnosis of comorbidity in ASD and internalizing disorders.