Background Children born preterm present higher rates of ADHD symptoms and autistic traits than the general population. Entorhinal cortical abnormalities have been related to cognitive deficits in the preterm population, and to psychiatric and neurodevelopmental disorders in the general population.

Aim To assess whether ADHD symptoms and relational problems are associated with changes in entorhinal cortical thickness in very low birth weight (VLBW) adolescents.

Design/methods Fifty VLBW (birth weight ≤1500 g) and 57 term control adolescents were assessed at 14–15 years of age with: ADHD Rating Scale IV (mother report), Strengths and Difficulties Questionnaire (SDQ mother report), Child Behaviour Check List (CBCL mother report) and Autism Spectrum Screening Questionnaire (ASSQ). Entorhinal cortical thickness (mm) was obtained using an automated MRI segmentation technique (Freesurfer). Associations were analysed by linear regression, adjusted for age, gender and socioeconomic status, and corrected for multiple comparisons (Benjamini-Hochberg procedure).

Results VLBW adolescents had higher ADHD and ASSQ scores than controls. On MRI, they had thinner entorhinal cortex compared to controls. Thinner entorhinal cortex was associated with higher ASSQ scores (Left: B=-0.946 (-1.517 to -0.374), p = 0.002; Right: B=-0.759 (-1.308 to -0.210), p = 0.008), and higher SDQ Peer Problems Scale scores (Right: B=-0.254 (-0.459 to -0.050), p = 0.016).

Conclusion Relational problems were associated with entorhinal cortical thinning in adolescents born preterm with VLBW, while associations were not found for ADHD symptoms. The different association in the two symptom groups with the entorhinal cortex might help to identify deviant neural structures and their relation to specific mental disorders.