Psychopharmacology is the branch of scientific deal with the study of the effects drugs have on mood, sensation, thinking, and behavior. It is different from neuropsychopharmacology, which deal with the correlation between drugs induced changes in the function of cells in the nervous system and changes in consciousness and behavior of an individual. It is also the study of the use of medications in treating mental diseases.

The use of drugs to alleviate the symptoms of mental diseased make psychoactive drugs, especially antipsychotics and antidepressants drugs which is among the most widely prescribed drugs today. Much debate surrounds the use of stimulants agents to treat attention that deficit problems and the side effects of antidepressants drugs, especially for children.