Neuroimaging studies of normal brain maturation demonstrate a continuous increase in parietal thickness reaching peak values around age 12, followed by a steady decrease over subsequent decades (32). In terms of neurodevelopmental abnormalities, our results may be cautiously interpreted as evidence for a relationship between the expression of OCD and disturbances in factors influencing radial cortical expansion, which influences gray matter thickness rather than factors influencing the tangential expansion that determines the overall surface area (33). In this context, our results could indicate an altered cortical maturation in OCD resulting in a thinner parietal cortex in early childhood, persisting into adulthood, although further confirmatory work using longitudinal samples is needed.
