Psychopharmacology is the study of drug-induced changes in mood, sensation, thinking, and behavior. The field of psychopharmacology studies a wide range of substances with various types of psychoactive properties. Common areas of interest are drug prescription and the appropriate use of drugs for psychiatric illness and for neuropsychiatric conditions. Some psychologists interested in psychopharmacology will focus on the behavioral effects of psychoactive or central nervous system medicine, drugs, and other chemicals of interest. Psychopharmacologists need to understand all the clinically pertinent essentials of pharmacokinetics (how the body affects medication) and pharmacodynamics (how medications affect the body). Often psychopharmacology is a combination of methods in psychology and pharmacology to study the interaction of behavior, drugs, and other environmental factors in animals and humans.