I believe that mental health issues have always been around to some degree. However, in today's society people in general are more sensitive to it. In the past the person would have been told to just "suck it up" and "deal with it". Not so anymore.
Social media allows for more people to be more aware of issues and, as such, social media also gives everyone a voice and in today's society people often times use social media to gain attention and/or are compelled to share everything about their life.