Subject you want

There are many subjects that people study. Some people study common subjects like math, science, and language. Some people study unusual subjects like psychology or zoology. However I want to study about psychology which is unusual and not common. There are two main reasons I want to learn about psychology.
First, to know about one person's mind is very difficult, but when I study psychology, I can know about one's mind very well. Psychology is a mental state what people think in their mind and prevent people from fighting.
Second, psychology can cure a mental disease. Almost all people cure mental disease by psychology. They have a disease in their mind. So the cure of that is psychology. Many physical disease can be caused by mental things. So when I learn about psychology, I can cure some beginning mental disease.
In conclusion, I want to learn about psychology because I can know about one person's mind and psychology can cure a mental disease. I wish people study many subjects.