这位老人坚信自己是国王，医生认为他患有妄想症。

The old man firmly believes he is a king, and the doctor thinks he is ___delusional.

尽管医生反复解释，他仍然固执地认为自己没病，这种想法太不切实际了。

Despite doctors' repeated explanations, he remained ___delusional about being perfectly healthy.