From Developmental Timing to Clinical Visibility: An Integrative Narrative Review of Sex-Related Neurocognitive...

Area of Science:

• Developmental Neuroscience
• Cognitive Development
• Clinical Psychology

Background:

• Traditional research on sex-related differences in child neurodevelopment often uses a simplistic binary comparison.
• This approach inadequately addresses the interplay of developmental timing, phenotypic expression, and clinical recognition.
• Existing frameworks struggle to explain inconsistent findings and unequal diagnostic rates for conditions like autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD).

Purpose of the Study:

• To propose a novel developmental-visibility framework for understanding sex-related differences in neurocognitive development.
• To integrate insights from developmental neuroscience, cognitive development, gender studies, and clinical research on ASD and ADHD.
• To shift the research focus from *if* sex-related differences exist to *when, how,* and *under what conditions* they become apparent.

Main Methods:

• An integrative narrative review synthesizing existing literature.
• Analysis of sex-related differences across three distinct layers: developmental timing, phenotypic expression, and clinical recognition.
• Case illustrations using autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) to examine clinical recognition.

Main Results:

• Sex-related differences in neurodevelopment are not uniform but vary across developmental timing, phenotypic expression, and clinical recognition.
• The developmental-visibility framework reconciles modest average effects, inconsistent behavioral findings, and disparities in clinical recognition.
• Underrecognized presentations, particularly in ASD and ADHD, highlight the impact of clinical recognition factors like compensatory behaviors.

Conclusions:

• The proposed framework offers a more nuanced understanding of sex-related differences in neurocognitive development.
• It emphasizes the importance of considering developmental trajectories, how differences manifest, and the social/clinical contexts influencing their visibility.
• Future research should explore the conditions under which neurodevelopmental differences become apparent, rather than solely focusing on their existence.