I don't know but am often struck by symptom overlap with Parkinson's / Alzheimer's ( which both can feature hallucinations and paranoia) , which is reinforced by some people responding to dopamine modulating medication, so there may be a mechanism / shared symptom pathway.
This may be more evident during PEM
Bipolar used to be often misdiagnosed as schizophrenia - particularly in females and there has been recent GWAS research into these disorders which have found various genetic associations which would account for symptoms .
There is a heritable aspect to many neuropsychiatric conditions and genetic research tends to explore both this aspect and drug targeting areas .
Given the wide variety of symptoms , these genes are across multiple areas / pathways and there is, perhaps unsurprisingly, an overlap with genetic research for other conditions which have wide symptom ranges.
Given the wide symptom range in ME there may be a genetic overlap with many conditions , which may have some relevance. ( offering hope for shared research and for drug repurposing /development)
I think there may be genetic predisposition for many things , it's a trigger that's needed to activate a process .
As genetic studies become both more commonplace and start to drill down , we might be able to unravel a bit more .
Hopefully Decode ME will be the beginning of something