As someone who has recurring episodes of both depression and anxiety, it's quite nice at the moment since I formulated a general theory myself as to why this keeps happening. I believe (I do have a medical background though) that it's due to an inbalance between available bloodsugarsupply to organs,as well as bad nutrition. In proper English: if you live a sedentary lifestyle where most of your energy goes to your brain since it already gets the highest percentage of energy usage (brain 19%), and the other organs won't need as much since youre not doing much physically, the brain has far too much energy available and therefore wastes it on extra 'processing' such as e.g. overthinking and negative 'extra' thoughts.

I currently solved this by trying to: -eat as healthy as possible (better quality of available energy) -doing sports at least twice per week (trying to equalize energy distribution between organs) -intentionally sleeping <8 hours per night and embracing the slight exhaustion throughout the day since the brain doesn't have the extra power to annoy me with unnecessary Bullshit

I hope that whoever reads this and wants to try it out gets as much help out of it as I do.

Pm me if you have questions