A study published in the Journal of Social Neuroscience has found that religious experiences are like being on drugs.
The study monitored brain activity of 19 devout Mormons when they were exposed to prayer, scripture reading and religious quotations.
There was activity in the areas of the brain central to reward, which is similar to when people take drugs.
These 'reward' feelings included: "A profound sense of elevated mood (euphoria), noetic insight, ineffability, and a sense of integration within oneself and with others."
Activity in the nucleus accumbens was also recorded which is associated with addiction.
You can read the full study here.