Research in the field of “Spirituality and Health” has been growing, with spirituality/religiousness (S/R) being consistently related to both physical and mental health. The objective of this article is to provide an updated review of the current scientific evidence on the relationship between S/R and mental health, highlighting the most important studies. As a secondary objective, the mechanisms that explain this relationship and the interventions that utilize this information in treating mental disorders will be discussed. The findings reveal a large body of evidence across numerous psychiatric disorders. Although solid evidence is now available for depression, suicidality, and substance use, other diagnosis, such as post-traumatic stress disorder, psychosis, and anxiety, have also shown promising results. The effects of S/R on mental health are likely bidirectional, and the manner in which religious beliefs are used to cope with distress (
i.e.
negative and positive), may affect mental health outcomes. Despite these findings, the mechanisms that explain these associations and the role of S/R interventions need further study. Concerning clinical practice, mental health providers should ask patients about S/R that are important in their lives to provide holistic and patient-centered care.