I'm pretty sure there are instances of demon possession, in which case your boilerplate response would be incorrect.
From memory, I think such possession constitutes one of the grounds for being exonerated for one's actions in the Vinaya. Whether 'demon possession' is literal, or whether it might be referring to mental illness, epileptic fits or something else, I'm not sure.
Either way, if I were you, I'd hold off in responding in such a way until you get confirmation, unless you wish to risk misrepresenting the Dhamma.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
"To argue with a person who has renounced the use of reason is like administering medicine to the dead" - Thomas Paine