I mostly emphasize the potential for positive effects of religion on the individual (1). After all, if religion made life more difficult, why would it crop up in virtually every society? Yet, religious people often shoot themselves in the foot with their choice of damaging practices.
Examples of voluntary self harm abound (2):
Each of these examples involve voluntary pain, discomfort, or risk that might be explained as ways of expressing, and increasing, commitment to the religion. Whether they should be classified as “sick” depends on whether one asks an insider or an outsider.
Religious rituals may be costly to the individual without damaging their way of life. Yet, some religious are extremely damaging. Members of an end-of-the-world cult are liable to quit their jobs and give away all of their property.
Some religions damage an entire society and these are categorized as “sick” (3).
The cattle cult of the South African Xhosa is a case in point where religious sacrifice of the cattle herd induced mass starvation in the mid-19th Century.
A young girl called Nongqawuse reported that she encountered three spirits who told her that all of the Xhosa cattle must be killed and all of their crops destroyed. Xhosa warriors would then return from the dead and expel the white invaders. The ancestors would bring cattle herds and huge fields of ripe corn would instantly appear. Chief Sarhili ordered that the spirits must be obeyed. Mass starvation followed. Some 50,000 Xhosa died from famine in 1867. The cattle cult soon disappeared. The tribe recovered, of course, the most famous contemporary member being Nelson Mandela.
The Shakers were not so fortunate. This religion made the mistake of banning sex so that they had to rely upon proselytism to keep going. It is reduced to a handful of members and will likely die with them.
The fact that religions can sometimes be very bad news for their followers does not mean that stable surviving religions are dysfunctional. The cattle cult is gone and the Shakers are almost finished and the same is true of other truly sick religions.
Sick religions often emerge in times of great change or unusual social conflict. They do not last, however. Natural selection lays them low.
Very damaging religions get weeded out by natural selection acting on their members who lead shorter lives and leave fewer descendants to carry on their damaging belief systems.
On the other hand, established religions exact ritual costs that are great enough to unite the members but not so great as to reduce their survival and fertility.
1. Barber, N. (2012). Why atheism will replace religion: The triumph of earthly pleasures over pie in the sky. E-book, available at: http://www.amazon.com/Atheism-Will-Replace-Religion-ebook/dp/B00886ZSJ6/
2. Sosis, R. (2004). The adaptive value of religious ritual. American Scientist, 92, 166-172.
3. Edgerton, R. B. (1992). Sick societies. New York: Free Press.