Thank you for the links. I will deal with the main points discussed in these articles and explain why Christianity does not fit the requirements of a shared psychiatric disorder like folie à deux.
"Shared psychotic disorder, also known as folie a deux ("the folly of two"), is a rare condition."
Christianity is far from rare. There are Christians all over the world, from all walks of life who have no direct links other than their faith, and nothing else in common.
"The delusions are induced in the secondary case and usually disappear when the people are separated."
This has not occurred with Christians. In fact, the opposite is often true. Even when Christians have been arrested, and put in solitary confinement (sometimes for years) tortured and mistreated, with absolutely NO other Christians or loved ones to talk to, their beliefs do not "disappear." In fact, such Christians often become even more certain of their faith.
"In most cases, the person in whom the delusions are induced is dependent on or submissive to the person with the psychotic disorder."
This is not how the Christian faith works or is shared. (Not when its shared as it should be). Christians see each other as brothers and sisters in Christ, and a true Christian does not demand that another Christian simply submit to their authority in all things. Interestingly enough, Christianity thrives the most in persecution, when those in power are telling Christians NOT to believe and threatening them with torture, imprisonment and even death if they don't renounce their faith.
"The people involved often are reclusive or otherwise isolated from society and have close emotional links with each other."
Christians are far from reclusive or isolated from society, quite the opposite actually. We live in the same world you do and we freely engage with those who do not share our beliefs. There are Christians in all workplaces and public spheres, we do not just hide away. (Which is why there is a site like this for example, and many Christians here who freely engage with those who do not believe as they do.)
Christianity fails to meet the specifications of folie a deux. And this is why you will not find any reputable source that says differently.
It is also why you will not find Christianity listed as a mental disorder in the
DSM-5.
I stand by my position. Christianity is NOT a mental illness.
Then you didn't go to a very good college.
Actually, I did. How do you know otherwise?