GM mapping studies cannot be used yet for diagnostic purposes, but they have provided convincing evidence for the neurobiological specificity in neuropsychiatric illnesses such as COS or bipolar illness, which have partially overlapping clinical presentations. Many of these changes and dynamic trajectories have now been replicated in independent samples of subjects and have even been tracked before illness onset, as they emerge in those at risk for bipolar disorder (Gogtay, Ordonez et al., 2007) and schizophrenia (Pantelis et al., 2007). This early tracking of GM changes is of interest, as it means that imaging has a growing role in evaluating treatments that may resist the spread of pathology in the brain.
