Do you believe Middle Child Syndrome exists?

Hello. Middle child here, and I was wondering, do any of you believe Middle Child Syndrome exists? Pretty much what is means is that the middle child is neglected more than their siblings and are more likely to be depressed and have anxiety and self-esteem issues.
I see a lot of people just brush this aside and believe it doesn’t real or that it doesn’t matter. What about you? What are your thoughts on it?