How did behavioral medicine develop vs developmental psychology?

Developmental : Psychology said/says that you need to change your thinking to change your behavior. But a guy by the name of aaron beck said that you can change behavior first and that will help change the thinking.

Growth vs behavior : Developmental psychology concerns itself with studying stages of development from prenatal stages through death in organisms human and animal alike. Behavioral medicine concerns itself with the study of human and animal behaviors, and how they can be altered or changed for the betterment of the organism, be it human or animal.

Clinical trials/obs: Behavioral medicine eveloped through clinical trials to determine the effectiveness of different medications in treating clinical disorders. Developmental psychology is concesrned with child development and gathered inforation thruough observing and testing children from infancy through adulthood