Hi. I am a chronic overthinker. Nice to meet you!

I wonder if the reason people decide to come to the world this time around with this type of brain is because our broader self/spirit knew that having the ability to hyperfocus, if you can train it like a muscle, eventually gives you the ability to have new, weird ideas, something that from non-physical must seem like an awesome thing. Of course, so long as you're tending to do what most humans do, just bopping along, responding nearly 100% to what you see around you instead of generating your own vibrations, hyperfocus can be pretty tough, because it produces self-reinforcing feedback loops. "The person I'm dating hasn't called me. I'll obsess about that for a while. Now I'm producing a powerful vibration of "Why don't they call?!?" And the LOA is matching that, and they aren't calling." etc.

(Of course this kind of thing happens with everyone, including non-over-thinkers, but it seems from my own experience that overthinking means that you can really, really focus on the thing you don't want, with all the results you'd expect.)

Anyway, here are my main conclusions, for whatever they may be worth to others:

1) Learn to meditate. Especially learn to meditate in the style taught in Zen meditation (see: Full Catastrophe Living or any other mindfulness text for more), or check out this ultimately very similar system: "Most effective meditation technique ever". Meditation has let me get more comfortable observing my thoughts and moods as weather patterns, rather than as real, observable reality I must immediately become profoundly emotionally involved with. "Oh, I am having anxious feelings in my chest after that phone call" vs. "I feel incredibly anxious and I feel catastrophic thinking coming on oh god they probably all hate me".

2) Distraction. If you have a hyperfocus brain, it's really hard to talk yourself into ignoring things. I think of my brain like a nervous dog, in that it is much easier to get the nervous dog to calm down by giving it a specific job to do ("Go into the kitchen and get your ball") than by demanding that it lie down and be silent. I learned this from reading about people who train animals using operant conditioning methods: if the bird you're trying to train keeps trying to land on your head, you don't try to teach the bird "Don't land on my head, jerk!" Instead, you train it to land in a specific place that is okay with you. A very different emotional approach, for me.

So I have gotten a lot of benefit from trying to train myself to not just not think about what is unwanted, but to actively choose to think either of what is wanted, or, if the vibrational difference is too big and I just can't get close to those wanted thoughts yet, to change the subject and think about something else that is very interesting to me. That feels critical to me, to seek out something that is actively engaging. (I read a lot of non-fiction about topics that are interesting, but not grim. Stuff like Bill Bryson is good for this, for me.)

"How do I control my periodic over-thinking?"

Remove your desire, your resistance, to control. The more you try to control the more unnecessary 'baggage' you will attract. Let go of controlling and allow yourself to flow into the vibrational frequency that is representative of your joy.