Delusion is an important symptom in psychiatry practice and can be a sign of a serious mental disease. Many psychiatric disorders include delusions in their clinical presentations. There are different theories about the nature of delusions but one of the most dominant ones is that delusions are beliefs in essence. In this paper, we suggest that this shared doxastic nature of delusions and beliefs, alongside DSM-5's subjective definition, makes it difficult for psychiatrists to distinguish delusions from non-pathological religious beliefs. This difficulty can lead to noticeable consequences.