Yes, but sometimes it is more intentional than others
While none of my characters are directly based off of my self, many of them share my non-binary gender identity. They struggle with similar mental health issues, like anxiety triggered by crowds or touch. Occasionally, they even like the same things as me, like Star Wars and vegetable gardens.
Of course, there are instances where I write characters that are opposite of me and have almost nothing in common. Sometimes I need to escape my world and truely become someone else while I am writing.
Yet more often than not, it’s hard to fully filter myself from my creations, and when the ones with bits and pieces of me sewn through are more authentic, why bother filtering?
Authenticity is important. Representation is important. My experience with mental health and gender may not quite be like someone else’s, but that is kind of the point, isn’t it?
People do read for entertainment, but they also read for education. Ideally, both happen at the same time. If my book can keep people entertained, make them feel things, keep them turning pages and teach them a little something at the same time, then it was success.