They don't have a test as such. They diagnosed based on our reported behaviour changes (a couple of which are apparently real give aways). And they do other medical tests to rule our other potential causes (they did bloods & checked organs). They've given her antidepressants & a drug that boosts blood flow to the brain. I don't want to jinx it as obviously still early (only 4 tablets) but she seems lot brighter today, and last night for first time in weeks she slept in one of her beds (as opposed to the kitchen floor)