Quote:DSM-5 definition of mental disorder
A mental disorder is a syndrome characterized by clinically significant disturbance in an individual's cognition, emotion regulation, or behavior that reflects a dysfunction in the psychological, biological, or development processes underlying mental functioning. Mental disorders are usually associated with significant distress or disability in social, occupational, or other important activities. An expectable or culturally approved response to a common stressor or loss, such as the death of a loved one, is not a mental disorder. Socially deviant behavior (e.g. political, religious, or sexual) and conflicts that are primarily between the individual and society are not mental disorders unless the deviance or conflict results from a dysfunction in the individual, as described above.
If we're talking about medical definitions of insanity, it is normal to say that insanity impairs one's ability to function well in society. So in the above definition, the word "dysfunction" is key. And the idea that to be a disorder, a condition is usually "associated with significant distress or disability in social, occupational, or other important activities."
In other words, insanity means you're troubled. It doesn't mean you believe something which we far superior atheists think is silly.
I think, for example, that somebody who is into QAnon isn't necessarily insane. Misinformed, yes, but not insane. But if it gets to the point where his QAnon obsession makes him lose his job and his family, and he moves to a trailer in the desert and starts shooting at police, then he may well be insane. It has become self-harm.
So I think that if someone faithfully practiced the Catholic mass, even to the point where he believes in the whole bread=body thing, it doesn't necessarily mean he's insane. In fact some people get a lot of comfort from this -- if their religion makes them feel that they are integrated with the Logos of the universe and blessed by grace, it could give them a source of happiness that isn't available to you or me. I'm not saying we should believe whatever makes us happy -- only that we can't judge other people's sanity based on how far their beliefs deviate from our own.
The last time I was in Florence I went to a church to see frescoes by Maso di Banco. I was sorry to find that they were in a chapel which was closed to tourists, and only open to people who actually wanted to do what the church was there for -- pray. As I was rudely peering around the gate, a very well-dressed and entirely sane-looking man came in, crossed himself, knelt down, and prayed for about five minutes. It occurred to me that he had a source of comfort and happiness which will never be available to me. Of course I don't know anything else about him, but I see no reason to believe that his metaphysical or supernatural beliefs made him insane.
