Computer modeling of interactions between and among cortico and subcortical areas of the human brain, for example in a normal and a pathological state resembling schizophrenia which pathological state has inputs representing the effects of a drug(s), for the purpose of using the outputs to predict the effect of drugs in psychiatric and cognitive diseases on one or more clinical scales. Diseases that can be modeled include psychiatric disorders, such as schizophrenia, bipolar disorder, major depression, ADHD, autism, obsessive-compulsive disorder, substance abuse and cognitive deficits therein and neurological disorders such as Alzheimer's disease, Mild Cognitive impairment, Parkinson's disease, stroke, vascular dementia, Huntington's disease, epilepsy and Down syndrome. The computer model preferably uses the biological state of interactions between and among cortico and subcortical areas of the human brain, to define the biological processes related to the biological state of the generic synapse model, the striatum, Locus Coeruleus, Dorsal raphe, hippocampus, amygdala and cortex, as well as certain mathematical relationships related to interactions among biological variables associated with the biological processes.