It is the branch of science that deals with the study of the effects of the drugs or medications which affect the mind and behavior and are used to treat mental disorders. This firequiresuire continuous study in order to understand all the clinically relevant principles of pharmacokinetic (the hat body does with the medications) and pharmacodynamics (what drugs do to the body). These pharmacodynamic and pharmacokinetic studies of the drug include the major parameters like protein binding, half-life, Polymorphic genes, and drug-to-drug interaction.