The findings of profound GM loss in illnesses such as schizophrenia raises an interesting debate about whether the cortical GM loss is just a perceived loss resulting from the encroachment of continued white matter growth, a process that normally extends through the 4th decade (F. M. Benes, 1993; F. M. Benes, Turtle, Khan, & Farol, 1994; E. R. Sowell et al., 1999); in fact, myelination may continue over the entire lifespan, with deteriorative processes beginning to outweigh positive changes by the mid-forties. We examined the white matter encroachment explanation in our recent analysis using tensor-based morphometry (TBM), in which we visualized average profiles of white matter growth in COS and healthy controls throughout the brain (Gogtay et al., 2008). We compared 3D maps of local white matter (WM) growth rates in COS patients and healthy children over a 5-year period, based on analyzing longitudinal brain MRIs from 12 COS patients and 12 healthy controls matched for age, gender and scan interval. COS patients showed up to 2.2% slower growth rates per year than healthy controls in WM (p=0.02, all p-values
