When writing a research about how social media declined interpersonal communication among student, can I write?

[I_I]

about how it affects their personal relationship?
If you could please give me some idea on which area I could focus, it would be greatfully appreciated.

[Jepchamp]

If you find valid research about how this affects personal relationships, then of course you can use it. I just hope you write the paper better than you wrote this question.
I think you have an area on which to focus--you are writing about how social media haev affected interpersonal communication among students. Now you need to go to the library and ask the librarian to help you find journal articles on this topic.

[Alyssa]

Yes you could write about how social media became an impediment to interpersonal communication. You are going to have to give specific examples though. The easiest way would be to use anecdotes( your personal experiences), but I wouldn't suggest that because they lack credibility. For this kind of essay I would always suggest a three part thesis essay : This is so and so because of 1)....2)...and 3).... In your case, you could probably write that : Social media declined interpersonal communication among students because 1) social media are faster and more efficient, 2) social media made interpersonal communication seemed outdated, 3) social media takes away the pressure of interpersonal communication since you are not really facing the person.
With these three in mind, you can then start looking up examples regarding each topic. Another way would be to name one thesis: Social media declined interpersonal communication among student because it it quicker and more efficient. Then you can find three examples backing your claim.