There's a YouTube channel named 'Living well with schizophrenia' in which the protagonist is talking about her own story and suffering with this mental disorder. Recently she announced she'd started her ketogenic diet and so far so good, she's symptom free and slowly tapering off her medication.
Ketosis is an interesting topic. There's also emerging research suggesting that it can play a role in the development of cysts for those who have APKD (Polycystic kidney disease). [1]
[1] https://www.cell.com/cell-reports-medicine/fulltext/S2666-37...
Previous discussion:
https://news.ycombinator.com/item?id=20421989 Chronic Schizophrenia Put into Remission with Ketogenic Diet (psychologytoday.com)
July 12, 2019 (14 comments)
Keto is also being studied for bipolar. Many anecdotes available on YouTube and elsewhere. It appears mental illnesses have in origin metabolic / mitochondrial dysfunction, through a combination of environmental and genetic factors.
They were using keto for epilepsy as far back as the 1920s.
https://en.wikipedia.org/wiki/Ketogenic_diet
Then drugs came out and everyone ran for the quick fix.