Brain discovery suggests source of lifelong behavioral issues. Improper removal of faulty brain cells during neurodevelopment may cause lifelong behavioral issues, new research suggests. The finding also could have important implications for a wide range of neurodegenerative diseases, such as Alzheimer's and Parkinson's. Source 3b.
Sometimes we see psychopaths and sociopaths as choosing to be this way but a lot of the times they are just wired differently or have a chemical upset within their bodies that makes them this way. In other words its natural for them while it may seem abnormal for us.