Some people have a positive outlook in life, always hopeful and free of worries. Some people are always negative, seeing the worse in every situation. We might think it's because they are who they are, it has to do with this person's personality, character, or the experience they have gone through. It's true, maybe. But the chemical makeups in our brain can also affect the way we think, the perspectives we take, and whether or not we see a glass as half-full or half-empty. In other words, we may or may not have control over how we think.
Have you met such person, or are you that person? When you fly somewhere, you always fear that the plane is gonna crash. Or when your loved one is ridiculously late, you think that they must be in some kind of accident. If the reason or the outcome is unknown, you always think about the negative, you can't help it, you just cannot help it. That is all that you think about in your head.
I used to be like that, for the first 22 years of my life. Even when I was a child, I was lacking the naiveness of people my age. I would be so worry-sick whenever my parents had to go on a business trip. As I got older, things just got much worse. I would even lose sleep at night thinking about all the scenarios that would go wrong. I had heard all kinds of inspirational quotes, but I was incapable of thinking that way.
After being on the right medication and eventually figured out the right amount (after 2 years), I have since become a really positive person. Being optimistic is a default, it's effortless. My personality has also changed. I cannot even relate to the person that I used to be. A friend from high school reunited with me recently and she could tell the changes by just looking at "my expressions". Another thing I find it interesting is the fact that I used to LOVE to watch horror films. But now, it would haunt me for days. It's the only type of movie that I would not watch.
On the other hand, my mom said that she used to be a fearless and sassy young lady. She would walk ahead of my dad when they were venturing into an unknown territory. But after menopause, and after her health has declined because of aging, she has become an introvert, not knowing what to say in a social gathering and mildly pessimistic in almost everything. Only the fact can change her previous feeling and perspective toward uncertainties.