Being a member of an organised religion has been found to have many mental and physical health benefits but at the same time many bouts of severe mental illness feature religious delusions. A year long study of 48 young adults with schizophrenia and bipolar disorder in the U.S. looked at the way people interpreted their mental illness in the light of their religious beliefs to see how this affected their mental health. The researchers found that those people who saw their mental illness as part of God's plan or as an opportunity for spiritual growth had better mental health than those people who saw their illness as a punishment from God or who felt that God was unable to help them in their distress.
Phillips III, Russell E. and Stein, Catherine H. - God's will, God's punishment, or God's limitations ? Religious coping strategies reported by young adults living with serious mental illness Journal of Clinical Psychology June 2007, 63(6), 529-540