I have ADHD, autism, and major depression, and meditation has been a fairly powerful tool for me (when I can will myself to use it) when it comes to straightening out my thoughts so my brain isn't a big bowl of stressful spaghetti.

What's worked for me is just allowing the thoughts to race, but not allow myself to interact with them. Eventually, they'll run their course and settle down.

In practice, it kind of looks like this: I'll focus on my breathing, but I won't worry too much about quieting my mind. I only meditate when I'm extremely distraught about something. So naturally, the worries will rise to the surface and try to take over. While I'm focusing on breathing and settling down, the thoughts will come. Money issues, loneliness, responsibilities I'm avoiding, depression, dissatisfaction, etc. I'll allow the thoughts to come into the forefront, and I'll "look" at them. I'll acknowledge them, I'll allow them their space. But I won't let myself to bring them into focus and give them any type of thought. I won't engage with them. I'll just...let them be. Objectively. Once I observe the thought, it'll usually pass by and make room for the next stressful worry to show up.

EVENTUALLY, the majority of the things that are bothering me will have made an appearance. I'll observe each one, and let it pass by. After years of practice, I've learned that the thoughts and worries will run their course and I'll finally have the space to truly focus on my breathing and decompress. After all is said and done, I'm usually left with relatively organized thoughts and I am able to think clearly, without everything swimming around in my head, simultaneously trying to scream at me.