One of my DC has adhd as well as autism and we started medicating 2 years ago. I wish we had done it sooner. It was only when his specialist school provision called an emergency annual review, to say they couldn't do any more as he just couldn't focus on anything. Within 2 days school said the difference was incredible.
It's not a miracle, we don't medicate at weekends or holidays. The side effects are he doesn't eat at all during the day (absolutely nothing) and as a consequence he lost a lot of weight and is now very slim. It works at school for him to calm down and concentrate but he knows it changes him and doesn't like how it makes him feel.
We have major problems with defiance too. In fact I am looking at the moment at the differences between ODD (oppositional defiance disorder ) and PDA (pathalogical demand avoidance). My son meets many of the criteria for PDA. There are some good strategies to help with this behaviour, have a google there are plenty of articles, some of the strategies may really help you.
Going back to your question (sorry), you have to have a hard skin, and that is not easy. I don't like having to justify why my son does something, I worry it sounds like an excuse, but sometimes it is necessary. People will judge, you can try an educate them, some will be willing to listen, others wont. Personally in public, I try and stay calm, ignore others and just focus of him using a calm slow voice, do not engage in argumentative chat.
My son tells me he cannot think about what he says, it just comes out his mouth, his actions are automatic, he cannot think about what he is doing, he just does it. He is not being naughty, his brain is wired differently, he is not choosing to be like this.
My neighbours are very good and understanding, they joke they all have their own issues and everyone is very tolerant. I don't know what your relationship with your neighbour is like, but you could try talking to them, let them know your son has ADHD and how difficult it is for him and how it impacts his behaviour.
I really do empathise, it is unbelievably tough a lot of the time.
I hope some of that helps. 