When is a Religious Belief Delusional?

[chimp3]

RN here. The definition of delusion clinically is a fixed, irrational idea that is not shared by others. 

 "I am Harry Truman!" is an example of a delusion that I witnessed a person experiencing.

 " Jesus is King" is just a belief that millions share. 

I am trying to do mentally ill people a service by not associating their disease process to the bullshit perpetuated by religious people.

There is no restriction on delusions that they cannot be shared with others: (from Marriam-Webster)

Definition of delusion

1 a : something that is falsely or delusively believed or propagated

• under the delusion that they will finish on schedule
  

• delusions of grandeur
  

b psychology : a persistent false psychotic belief regarding the self or persons or objects outside the self that is maintained despite indisputable evidence to the contrary

• the delusion that someone was out to hurt him
  

; also : the abnormal state marked by such beliefs

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Does this apply to religions? At the very least, it applies to beliefs in supernatural deities that affect day-to-day lives of people. Combined with the confabulation (called apologetics) that is typical of religion (and delusions), it is hard to see a way that most religions are NOT delusional.

As I mentioned, antipsychotics help with psychotic delusions. They have no effect on religious beliefs commonly held.