"In the vast majority of cases, people kill themselves due to abnormal brain chemistry."
Correlation is not causation.
If every belief we disagree with can be put down to chemical imbalance, it says nothing for reason, or for free will. It is trivialising and demeaning to to those involved to simply sweep aside any idea of perhaps changing the society we live in, and correcting its failure to provide habitats suitable for human existence. No, just keep on with the same shit, keep creating the same problems and then blame it all on a chemical imbalance. How patronising.