2026 ECNP Congress

PS01-1138

Different sex profiles in preschool children screened for autism spectrum disorder in primary care

Ángela Ormandi Santiago — C. Robledo Mateos, V.B. De Vena Díez, C. Fernández-Álvarez, D. Z. Wojcik, Á. Bejarano-Martín, S. Manso De Dios, R. Casado Vara, R. Canal-Bedia · University of Salamanca, Doctoral School of Neurosciences, Salamanca, Spain

2026 ECNP Congress

Introduction

Research on autism spectrum disorder (ASD) has highlighted persistent differences between males and females in prevalence and clinical presentation [1]. These disparities may not reflect true biological (sex-related) differences, but rather biases in detection and diagnostic practices derived from male-centered conceptualizations of ASD [2]. During early childhood, the influence of gender-related socialization is still limited, which allows for a more accurate exploration of sex-related neurodevelopmental profiles. Understanding these early differences is essential to improve the sensitivity of screening and diagnostic procedures [3].

Objectives

To analyze sex-related differences in the psychological and behavioral profiles of preschool children screened for ASD in community-based primary care settings in Spain, and to identify factors contributing to male overrepresentation in ASD diagnoses.

Methods

This retrospective observational study examined clinical records of 606 children (138 girls, 468 boys) aged 13 to 72 months who participated in a community screening program for ASD conducted in pediatric primary care services across several Spanish regions. All participants underwent standardized diagnostic assessments based on DSM-5 criteria [4] and the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2). Adaptive functioning was measured with the Vineland Adaptive Behavior Scales, and cognitive functioning with the Merrill–Palmer-R Scales of Development. Regression analyses were performed to explore predictors of ASD severity, using sex, cognitive, and adaptive scores as independent variables to determine their relative contribution to the clinical presentation.

Results

The male-to-female ratio among children meeting ASD diagnostic criteria was 3.8:1. No statistically significant differences were observed in the severity of core ASD symptoms between boys and girls, either in the 13–36-month or the 37–72-month groups. ASD severity was inversely associated with both adaptive and cognitive functioning (Predicted ASD Severity = 36.39 − 0.25 × Adaptation − 0.10 × Cognition; R² = .273, p < .001). This indicates that lower cognitive and adaptive skills are strong predictors of higher symptom severity across the entire sample. The inclusion of interaction terms with sex did not improve model fit (ΔR² = .003, p = .370). Although diagnostic patterns were largely similar across sexes, girls without an ASD diagnosis showed higher scores in communication and socialization domains than undiagnosed boys.

Conclusions

These preliminary findings suggest that the lower detection rates of ASD in girls are not explained by differences in symptom severity, but may be related to subtler behavioral manifestations and greater early social-communicative competence that reduce the likelihood of referral or diagnosis. Rather than indicating distinct “female phenotypes,” these patterns may reflect variations in how autistic characteristics are expressed and perceived in girls during early development. Improving the sensitivity of screening instruments and clinical criteria to these early sex-related variations is essential for achieving more accurate and equitable ASD identification in preschool populations.

Keywords: autism spectrum disorder, sex differences, early detection, diagnostic criteria, preschool children, screening, primary care

References

  1. Corbett, B.A., Muscatello, R.A., Blain, S.D., Ioannou, S., 2021. Camouflaging in autism: Examining sex-based and compensatory models in social cognition and communication. Autism 25 (6), 1580-1592.
  2. Loomes, R., Hull, L., Mandy, W.P.L., 2017. What is the male-to-female ratio in autism spectrum disorder? A systematic review and meta-analysis. J. Am. Acad. Child Adolesc. Psychiatry 56 (6), 466-474.
  3. Nazari, S., Lombardo, M. V., Ruigrok, A. N., Bullmore, E. T., Baron-Cohen, S., et al., 2023. Large-scale examination of sex differences in early childhood: Neurotypical children and children with autism spectrum disorder or other developmental concerns. Molecular Autism 14 (1), 40.
  4. American Psychiatric Association, 2013. Diagnostic and statistical manual of mental disorders, fifth ed. American Psychiatric Association Publishing, Washington.