I'm a layman but I read the paper. The paper's main points are that people with bipolar show a specific lack of some chemicals that Epstein-Barr Virus infections can cause, it argues that this theory would explain lithium being paradoxically good at treating BD (for some technical reasons it gets into), and further there's ample evidence that mood disorders and autoimmune disorders have a high comorbdity, with the author suggesting that the two are more deeply related.

Woah. So i should treat autoimmune to improve my mood? Like specific diet?

Extremely unspecific advice:

If you use too much toilet paper all the time then something is wrong with your diet and you should try figuring out what the cause is. Once your diet has improved you won't need more than one wipe.

I doubt this will help with bipolar disorder specifically though. This is mostly helpful for people who don't get enough fiber.

... but I love Taco Bell so much it hurts.

A mono vaccine is in development, so the more health problems that can be linked to mono, the better it will be for the vaccine sales.