Pharmacodynamics is the study of the biochemical and physiological effects of drugs on the body or on microorganisms or parasites within or on the body and the mechanisms of drug action and the relationship between drug concentration and effect. Pharmacodynamics is often summarized as the study of what a drug does to the body, whereas pharmacokinetics is the study of what the body does to a drug. Pharmacodynamics is sometimes abbreviated as "PD", and when referred to in conjunction with pharmacokinetics can be referred to as "PKPD".

Understanding the pharmacodynamic principles of antipsychotic medications can be very helpful in guiding clinicians in certain key aspects of psychopharmacologic practice, including medication selection, dosing, and management of adverse events. Presenting the clinically salient aspects of antipsychotic pharmacodynamics involves understanding the concept of how these agents differentially affect the dopamine system, and the range of binding actions on other monoamine receptors besides the family of dopamine receptors. Understanding the pharmacology or drug disposition of atypical antipsychotic agents - including their absorption, distribution, metabolism, and elimination - is essential, as these characteristics impact dosing, drug-drug interactions, withdrawal effects, and eventually the efficacy and safety of these medications. Side effects can complicate and undermine antipsychotic treatment in various ways by causing or worsening symptoms associated with schizophrenia, including negative, positive, and cognitive symptoms as well as agitation.