About mental diseases and kamma This question is built on top of another questions asked in this site (not all by me).

Based of these premises:

1) Kamma is not the only phenomena/process responsible for the current condition of beings. There are other processes apart from those borned from anthropologic interactions or from any kind of will/intention (e.g. weather conditions, geological events, biological diseases, etc.), which can affect our lives and states.

2) I heard from one user that ghost and other 'paranormal' entities (let's assume for a moment that they exist, and let's just consider what the suttas tell us) can control other's minds. And even if is not "the person itself" the one doing an action, the kamma will be ripen for that person eventually (and I insist, even if that person didn't have the intention of doing an unwholesome deed)

And the question: for those who believe in literal rebirth (i.e. the continuation of certain mind states and kammic seeds from one life to another after the break up of the body), what do you think it happens after biological death to those whose brains begin to malfunction as a product of some biological conditions or fortuitous event, such as a tumour, dementia or a lightning striking on someones head? 
What if those persons begin acting impulsively and heedlessly, even if before those misfortunes they had completely normal -or even wise- behavior? Will they rebirth in hell or something like that?

Thanks in beforehand for your time and patience!
I knew someone who was diagnosed as psychotic for most of her adult life. Psychiatric medicines were semi-effective in her case (so the psychiatrist called her "one of the lucky ones"), so apparently the symptoms were brain-related -- even if etiology is too complicated i.e. physical and environmental.

A couple of comments based on that...

It took years before finding how to get medical treatment, because she was never "an imminent danger to self or others" which is the usual legal requirement for imposing medical treatment. I interpret that as evidence that her intentions toward others were invariably or mostly kindly, even when her thinking was very confused (disordered in form and content). To the extent that "kamma is intention", I think that counts for a lot.

She expected to be reborn; but she didn't say where nor for how long.


MN 57 says something about being reborn as an animal -- given her great sympathy for ("mind of goodwill towards") animals, perhaps that (rebirth in the animal realm) is a possibility.
Conversely her "sins", such as those ever were, were all too human -- perhaps that means a human rebirth.
Perhaps she visited other realms (brahma- and otherwise) "in this life", experienced "paranormal entities" -- to that extent perhaps she developed some equanimity about future experiences.