Several studies suggest significant relationships between migration and autism spectrum disorder (ASD) but there are discrepant results. Given that no studies to date have included a pathological control group, the specificity of the results in ASD can be questioned.

To compare the migration experience (premigration, migratory trip, postmigration) in ASD and non-ASD pathological control groups, and study the relationships between migration and autism severity.

Parents’ and grandparents’ migrant status was compared in 30 prepubertal boys with ASD and 30 prepubertal boys without ASD but with language disorders, using a questionnaire including Human Development Index (HDI)/Inequality-adjusted Human Development Index (IHDI) of native countries. Autism severity was assessed using the Child Autism Rating Scale, Autism Diagnostic Observation Schedule and Autism Diagnostic Interview-Revised scales.

The parents’ and grandparents’ migrant status frequency did not differ between ASD and control groups and was not associated with autism severity. The HDI/IHDI values of native countries were significantly lower for parents and grandparents of children with ASD compared with the controls, especially for paternal grandparents. Furthermore, HDI/IDHI levels from the paternal line (father and especially paternal grandparents) were significantly negatively correlated with autism severity, particularly for social interaction impairments.

In this study, parents’ and/or grandparents’ migrant status did not discriminate ASD and pathological control groups and did not contribute either to autism severity. However, the HDI/IHDI results suggest that social adversity-related stress experienced in native countries, especially by paternal grandparents, is potentially a traumatic experience that may play a role in ASD development. A ‘premigration theory of autism’ is then proposed.

Several studies have reported anxiety disorders in children with high intellectual potential (HIP). However, there are discrepant results possibly as a result of methodological biases (different/absent definitions of HIP, small sample sizes, non-validated/adapted/specific tools for assessing anxiety and a single observational source).

To examine more thoroughly the relationships between HIP and anxiety in large samples of children using clear definitions of HIP, different observational sources and specific assessments of anxiety.

Children with HIP (n = 211, total IQ ≥130) were compared with children without HIP (n = 397, total IQ <130) for anxiety using different observational sources (child psychiatric diagnosis, parental evaluation and child's self-evaluation). Intellectual functioning was assessed using the Wechsler Intelligence Scale.

There were significantly more children with HIP who had anxiety disorders than children without HIP based on the child psychiatric diagnosis. Moreover, based on the child's self-evaluation, children with a high Verbal Comprehension Index (VCI ≥130) were significantly more anxious than children with a VCI <130, whereas children with a high Perceptual Reasoning Index (PRI ≥130) were significantly less anxious than children with a PRI <130. Finally, there was no significant relationship between levels of intellectual functioning and anxiety according to parental observation.

The results highlight the importance of using multiple observational sources and conducting analyses on different dimensions of intellectual functioning (such as VCI and PRI), rather than only on the composite total IQ score. High verbal potential might be a factor of vulnerability for anxiety, whereas high perceptual reasoning might be a protective factor. Further studies are necessary to understand better the mechanisms underlying these results.