The generation of “virtual twins” of patients (Avatars) through integration of multiscale data gained from both the clinical profile of the patient and - omics tools, could create an appropriate environment for stratification of patients in fitting cohorts of “virtual populations”. Physiologically based pharmacokinetic & pharmacodynamic (PB/PK/PD) models as in silico clinical trial tools can estimate the PK/PD profiles in specific populations. In this work we discuss examples of how patient Avatars could be exploited in the context of in silico clinical trials and help in identifying novel biomarkers for personalized diagnosis. The PB/PK/PD models, neuroimaging and - omics data, may be fused together to further advance current decision making processes in clinical practice.