As someone prescribed a medication that affects the mind, I remember this book haunting me for some time after reading it in grade school. Skimming it again tod

As someone prescribed a medication that affects the mind, I remember this book haunting me for some time after reading it in grade school. Skimming it again today, that same fear returns. Dementia and/or Parkinsons will eventually take my mind from me. After having two grandparents pass away in the last year, I've come to terms with that part. But when? Will it be worse for me?