Psychology studies human behavior, that is what I was taught since I was in high school, but for it to be considered and taken into account as a science it has to meet several requirements, one of them is that for a branch of knowledge to be considered a science the first thing it must have is a clear epistemology.
Epistemology in this case is very clear, since psychology aims to deepen the knowledge oriented to human behavior, however we must ask ourselves another question:
Does psychology apply the scientific method?
It depends on the perspective of study, since for example if it is experimental psychology if it applies the scientific method, since when studying the different variables that make the fundamental basis of psychology we will realize that it needs to apply the scientific method, since on the way new questions arise, and that the associated knowledge can be infinite.
The theory of relativity has helped us to understand that there is no absolute truth, and that everything depends on a lot of variables, so the context of analysis of each person will take a correct interpretation of each way, that is to say, for those who think that psychology is a discipline, they may be right, and for those who think it is a science, they may also be right.
The important thing is not to have limitations of thought, and it is also important to define the variables, the context and the environment in which the study and deepening of psychology can be performed.