It is generally grouped in the larger category of 'mystical experiences', which are often reported by people with instances of mania, schizophrenia and schizotypal behaviors, some anxiety disorders, etc.
It isn't a "mystical experience" OR illness, so why is it often grouped in the larger category? Again, 60-70% of the population report experiences of deja vu, so why are you attempting to specifically link it to mental illness? You aren't saying anythign remotely important or linked to psychology. Basically the only thing you are saying is "nutcases report deja vu", yet you sidestep the fact that 60-70% of the pop reports them. So, with that being said is 60-70% of the population nuts?
Of course not all psychologists ask about deja vu when screening/assessing for mental illnesses (an extremely broad category).
Yet that is not the way you were putting it out there, and I agree it is an extremely broad category which is why suggested you acknowledge this simple fact.
What I am saying is that when looking specifically at bipolar disorder, mania or manic behaviors, schizotypal personalities / schizophrenia, they do often ask if the subject experiences deja vu.
They also ask when the last time the person ate breakfast, or how many hours of sleep they got last night. Again, the question of deja vu is NOT always asked, and if it is asked, it depends on the condition of the patient/client, the test being administered, who is administering the test, treatment etc.