Integrating Ultimate and Proximate Explanations of Neurodivergence: Evolutionary Trade-Offs, Compensation, and Clinical Expression.

Elevated rates of major depressive disorder and anxiety disorders in neurodivergent populations are often interpreted as evidence that autism, attention-deficit/hyperactivity disorder, and affective disorders share intrinsic neurobiological pathology. Evolutionary psychiatry offers a different interpretation: neurodivergent trait profiles may reflect evolutionarily shaped cognitive variation whose consequences depend on ecological and social fit. Recent evolutionary psychiatry work has extended this perspective by interpreting the concomitance of neurodivergence with depression and anxiety through evolutionary trade-off, mismatch, and evolved affective defense systems. Here, this ultimate-level account is integrated with the pathogenetic triad, an operationalized cross-level framework that adds an individual-level account of how traits, adaptive capacity, burden, and environmental demands shape clinical expression. This synthesis suggests one pathway by which depression and anxiety may arise in neurodivergent individuals: chronic mismatch may increase compensatory demands and repeatedly activate evolved affective and defensive systems, particularly when regulatory buffering is limited or burden is high. The resulting framework helps reconcile neurodiversity and medical models by distinguishing natural neurodivergent trait variation from the mechanisms through which it becomes clinically impairing. Evolutionary psychiatry helps explain why neurodivergent traits persist and why mismatch may generate vulnerability; the pathogenetic triad helps specify how, when, and for whom such vulnerability becomes clinically expressed.