They are a tiny fraction of people who died from DNA issues.
People with personalities also have neurons and wonder of wonders a centural nervous system.
PS: Itβs hard to get good numbers for this stuff as but many things like drug use my pregnant mothers can cause significant developmental issues. But, everyone has several random mutations and mental problems from them seem to be far less common than other issues. Especially when you exclude things getting passed down over time and just look at new mutations.
