Actually, no author of the psychology of religion and spirituality can answer to it. There is no consensus today about the role of religion in spirituality matters, existing authors who argue in favor of a conceptual union of the both concepts as is the case of Kenneth I. Pargament and others that defend an independency between the constructs as Daniel A. Helminiak.
The article "Religion and Spirituality: Unfuzzing the Fuzzy" by Zinnbauer, Pargament and others is the hallmark of the conceptual union of religion and spirituality. It is a contested article.
In spite of this debate between proponents for a overlapping and advocates for a conceptual independency, the generality of authors agree in a blear demarcation line that varies from author to author to the point of contradiction.
The major setting of the debate is the area of psychometry with workings around conceptualisation.
I dare to say that to the present day there is no clear conceptualisation of spirituality, nor agreement in psychometry field, neither a substancial corroboration of metrical tests and other social and clinical research.
The "Handbook of the Psychology of Religion and Spirituality" edited by Raymond F. Paloutzian and Crystal L. Park addresses some core issues but due the psychometrical fragility of this area the generalisation of research to a unifying theoretical framework is not exempt of problems.