A book is needed for the mind to develop complex and amazing thoughts. Biographies in particular help us frame where we are in the world, and help ground us in our purpose and beliefs. The reading of books and biographies in specific help keep the society learning from its past, and help it evolve into something greater.
I do not believe biographies have mental health implications for those who read them. This seems like such an odd suggestion to me. I suppose it is possible, but I would assume the affects would be mild. Reading a biography isn't likely to make you go crazy but it may improve your ability to perceive things from other points of view. I suppose one could argue that this is indeed a mental health implication as it will help you in social aspects of your life.
Biographies do not have mental health implications for those who read them. Biographies help us to understand where the person went and where they are going in life. I think they are fun to read and help us understand our culture and the people that surround us and the people in the past.
I think overall people just get enjoyment from reading a biography of a person they are interested about, I don't see any negative or positive mental health implications coming from that, it's often just interesting to read about some ones life and the actions that they took to become well known enough to get someone to write a biography about them.
No, I do not believe that biographies have mental health implication for those that read them. I think that they are an informative way for one person to understand the life and times of another. Biographies may evoke strong emotion depending on who is reading them, but I do not think they have any mental implications.