Religious and spiritual factors are increasingly being examined in psychiatric research. Religious beliefs and practices have long been linked to hysteria, neurosis, and psychotic delusions. However, recent studies have identified another side of religion that may serve as a psychological and social resource for coping with stress. This paper reviews research on the relationship between religion and/or spirituality and mental health, focusing on depression, suicide, anxiety, psychosis, and substance abuse. The results of an earlier systematic review are discussed, and more recent studies in the United States, Canada, Europe, and other countries are described. While religious beliefs and practices can represent powerful sources of comfort, hope, and meaning, they are often intricately entangled with neurotic and psychotic disorders, sometimes making it difficult to determine whether they are a resource or a liability. The paper concludes that religious involvement is generally related to better coping with stress and less depression, suicide, anxiety, and substance abuse. Clinicians need to be aware of the religious and spiritual activities of their patients and recognize when those beliefs are distorted, limiting, and contribute to pathology rather than alleviate it.Religious and spiritual factors are increasingly being examined in psychiatric research. Religious beliefs and practices have long been linked to hysteria, neurosis, and psychotic delusions. However, recent studies have identified another side of religion that may serve as a psychological and social resource for coping with stress. This paper reviews research on the relationship between religion and/or spirituality and mental health, focusing on depression, suicide, anxiety, psychosis, and substance abuse. The results of an earlier systematic review are discussed, and more recent studies in the United States, Canada, Europe, and other countries are described. While religious beliefs and practices can represent powerful sources of comfort, hope, and meaning, they are often intricately entangled with neurotic and psychotic disorders, sometimes making it difficult to determine whether they are a resource or a liability. The paper concludes that religious involvement is generally related to better coping with stress and less depression, suicide, anxiety, and substance abuse. Clinicians need to be aware of the religious and spiritual activities of their patients and recognize when those beliefs are distorted, limiting, and contribute to pathology rather than alleviate it.