I know the part where they tell you you are the worst mother in the world and that you are supposed to take care of your children hurts. My son tried that on me again recently too.
The truth is that the only reason they say it is to try and guilt you into doing what they want you to do. Once you see through that, the manipulation doesn't work anymore.
As far as the mental problems, I am convinced that drugs will bring it out. How can you mess with your brain's wiring all the time and it not have an effect? There are so many people diagnosed with bipolar now and look how many people use drugs. I suspect rather than self-medicating, the drugs are causing the problems.
I have two sons. The one tells me I am the worst mother in the world and the other tells me I am the best mother in the world and better than any of his friends mothers. I know I gave both my children a lot of love, raised them the very best I knew how and yet they turned out so differently.
You have two other sons who turned out just fine. Let that be your consolation. Stay strong. You, your husband and your other sons deserve it.