In an attempt to investigate the relevant functions of genes implicated in psychiatric illness, the study of biological substrates has become of increasing interest. In particular, the application of so-called neuroimaging genetics – a technique based on in vivo brain measures - has illustrated how risk genes can modulate specific neural processes, translating gene effects on brain function and structure in a more meaningful way than the clinical association approach alone [5, 6]. Investigators, in general, have favored the study of effects of risk associated genotypes in the brains of healthy individuals [7–11], to circumvent the potential contamination of signal from non-genetic and/or illness-related factors (e.g. treatment, symptoms, smoking, general health issues) that make it difficult to interpret results in patients alone. On the other hand, studying “healthy volunteers” exclusively runs the risk of identifying a genetic effect in brain that has little or no relationship to the disorder itself.
