there are so many rules about words on this forum! ever hear of satire?
The rule of this forum is "don't be rude", which includes using derogatory terms for various categories of people.
However my advice was general, not just for this forum. Satire or not, some people will be extremely vexed if you refer to mental illness sufferers as "lunatics", and they might simply disregard what you have to say, even if it is legimate in content.
I am not ordering you to do anything, I am not a mod here. I'm merely giving a piece of advice which I believe you should consider seriously if you're going to treat the subject of mental illness with accuracy and respect.