I think what you may be referring to, and I believe your choice of words is correct when you say religious "mania". Actually, religiosity can be a symptom of manic depression. Everyone should know, however, that THIS HAS NOTHING TO DO WITH RELIGION, but is a manifestation of the grandiosity that is a symptom of the manic phase of bipolar disorder. If that is the case of the people you know whose religiosity you assume caused their decline, my guess it was a symptom of a real mental disorder - that it was a SYMPTOM not really the cause of the problem.
and, similarly...
could not this "porn addiction" be a similar flaw of a weak mind?
King Prout specifically cited "born-again christianity" as an addiction analogous to porn-addiction.
On the otherhand, your assessment:
"THIS HAS NOTHING TO DO WITH RELIGION, but is a manifestation of the grandiosity that is a symptom of the manic phase of bipolar disorder. If that is the case of the people you know whose religiosity you assume caused their decline, my guess it was a symptom of a real mental disorder - that it was a SYMPTOM not really the cause of the problem."
Spot on.