there's evidence that some of the symptoms are connected to food. One example would be pseudo allergic reaction, where you're reacting to something, but it doesn't show up in a prick test.
Instead you've got a time-frame of like 5 days, where when you ingest something, that something does something in the gut and the whole nervous system then reacts with higher levels of anxiety.
You can trigger this with your dog and cats, feed something that they wouldn't eat normaly, like pea protein or seafood - wait four days, watch their behavior over time.
personal account: I used to think someone is in my room and that someone wants to hurt me, and I'd see shadows at the edges of my view - until I went on carnivore diet. I also used to be depressed with adhd, which has improved a lot after switching to keto.
Nowadays, I pay more attention to what I eat and how I feel the next few days. Some day I had waffles, few days later I thought my coworker was planning on killing my dog. The internal dialogue goes haywire and discards all logic at some point.
There are a few tests, including SIBO and Candida as well as nutrient deficiencies that can cause this. I've never found an official diagnosis with my doctors, so I've been reading up on these topics since 2018 and am currently preparing for an exam as a nutritionist. But even in the materials there's not much about the relationships between all the parts.
The latest thing that worked for me, was taking silicea, usually women take it for nails and hair - seems to help the body to repair tissues, which would match trying to repair the gut lining (if it was broken, which is hard to prove/disprove). I got there because I saw some guy on youtube (3 hrs video), he'd been poisoned with rat-poison, and some of what he said matched some of my symptoms. And he was told to take silicea to help the gut lining - next step would be diversifying the gut microbiome.
Good luck out there, hope it helps.
I've been collecting some pointers and articles on https://github.com/cutestuff/FoodDepressionConundrum
