Aspects of the invention provide methods of screening for a mental disease selected from schizophrenia, psychosis and phencyclidine abuse and addiction in a subject or a subject population, diagnosing schizophrenia, psychosis and phencyclidine abuse and addiction in a subject by determining the magnitude of expression of at least one gene and providing tools for selection of a treatment and a list of therapeutic agents for the treatment of schizophrenia, psychosis and phencyclidine abuse or addiction based on said screening and diagnosis of a human or a nonhuman animal.
