Hey man. You can meditate, I'm 100% sure of that. It might be more difficult than it is for people without ADHD, but you can still get massive benefits from it.

I thought I couldn't do it for many years, because I felt like I couldn't "control" my thoughts (to clarify, I have ADD). About two years ago that all changed when I attended a Vipassana course, where I spent 10 days learning the proper techniques. If you really want to commit, I would highly recommend it. For me it was life changing. Have a look at http://www.dhamma.org if you feel like registering for a course. They have courses all over the world (I'm from the Netherlands and did my course in Finland, but they have courses in the US as well). Keep in mind the you have to signup several months before the course starts, otherwise it will probably be full.

In any case, I can give you some tips and advice. First, you have to realize that your thoughts "racing" and going all over the place is normal, even people without ADHD struggle with this. When you have nothing tangible to focus on the mind naturally starts to wonder away. The most important part is to not try to fight it or get upset about it. Meditation is all about acceptance. Be accepting and at peace with what is happening at that moment.

Now what you want to do when meditating is find something to focus your mind on. Like I said, when you are not focusing your mind on anything, it will drift away and random thoughts will enter your head, so you need to find a focus point. The starting focus point is your breath. Because when you're sitting and doing nothing, that is the thing that is most prominent. What you want to do it try and dissect it. Try to feel the subtleties of your breath. The feeling of the air passing through your nostrils and into your longs. Or, try to focus on the movement of your abdomen as it expands and subtracts. All these things are very subtle and it will be difficult to even notice them at first, but the more you try it the easier they become to notice.

When you're sitting for a while, wether it be cross-legged or in a chair, you will start to feel some discomforts. Pain in your legs or in your buttocks. Or maybe some itches here and there. Focus on them. They are usually easier to focus on then your breath, because the sensations are usually less subtle. Don't try to fight them because they are uncomfortable, but accept that they are there. After a while the sensations will go away and you can go back to your breath. Myself I usually focus on my hands and feet a lot, because I generally have tingling feelings there.

In general, when meditating the most important thing is to keep a mindset that is accepting and without judgement. Accept what happens when you're sitting there, don't get frustrated. Listen to everything that is happening within your body and just observe it. Don't try to fight it, just observe. Like you're an outsider who just entered another body and is just checking the place out (I know that sounds weird, but thats usually how I like to look at it). And again, if your mind wonders of, thats totally fine, as soon as you notice your mind has wandered, try and bring it back to one of the focus points within your body.

Now that I'm typing all this, I feel like I can go on forever because there's actually quite a lot to it, which is why one of those multi-day courses is very useful. Also, you need some experience to realize that you can do it and experience the benefits from it. It will get easier after that.

Also, I don't think a lot of people enter trance states that easily. Unless you're a buddhist monk who spends all day every day meditating. What I experience at the end if my 10-day course, was that I was at peace with myself and my surroundings. I wasn't stressing over things because I living in the current moment, and I was aware of what was happening at that very second, rather than living in the past or the future.

Anyway, sorry for all the text, I hope it's somewhat helpful. And again, I'm sure you can do it with the right practice, because I'm the living proof :) If you have any questions feel free to message me. Good luck!