Scientologists claim the 'e-meter' is a religious artifact, but were slapped by the FDA in the 1960s for making false medical claims about the device. Wikimedia Commons

Scientology is once again in the headlines with high-profile devotees like Tom Cruise and John Travolta facing divorce and scandal, respectively. Add to that mixture the fact that Paul Thomas Anderson's movie The Master, thought to be based on the controversial faith, is coming out later this year and you've got the recipe for some anxiety at Celebrity Centres from Los Angeles to Clearwater, Fla.

The Church of Scientology has drawn criticism and opposition from ex-members, activists and even national governments for some of its practices, which include requiring members to pay large sums of money to advance in rank. The church has also been accused of spying, kidnapping, and even causing the deaths of members.

But what is the science in Scientology all about? Certainly not psychiatry, which the church vehemently opposes.

Scientology's alternative to psychiatry involves auditing sessions that often make use of a device known as an electropsychometer or e-meter, which passes a small electrical current through a user. Scientologists, from founder L. Ron Hubbard on, used to claim that the e-meter and auditing can cure or treat various physical and mental illnesses.

But in the 1960s, after the U.S. Food and Drug Administration sued the church for fraudulent medical claims, a federal judge ordered Scientologists to label the e-meter with a warning notice detailing that it does not treat or cure illnesses and to restrict its use to religious counseling.

Today, Scientology refers to the e-meter as a religious artifact and a calibrated device used for measuring extremely low voltages and psyche, the human soul, spirit or mind.

Despite the church's dubious practices, many Scientologists have insisted the religion has had a hugely positive effect on their lives, but these sorts of anecdotes aren't hard enough evidence, social psychologist Carol Travis told Scientific American last October.

Every therapy produces enthusiastic testimonials because of the justification-of-effort effect, Travis said. Anyone who invests time and money and effort in a therapy will say it helped.

To really see if Scientology's methods have an effect, one would need to conduct a clinical trial in which people are randomly assigned to a group that receives Scientology-based therapy, or a group that receives no therapy, or a different method of counseling, Scientific American writer Michael Shermer pointed out.

Scientology views psychiatrists as corrupt and abusive, and has a strict policy against the use of psychoactive drugs. (In 2005, Cruise publicly chastised Brooke Sheilds for taking Paxil to treat post-partum depression.) A Scientology-affiliated group called the Citizen's Commission on Human Rights lobbies against the entire profession, calling it an industry of death. Anti-psychology propoganda, often using violent imagery, can be seen posted on the numerous Scientology-owned properties throughout Hollywood, which is home to the church's most star-studded Celebrity Centre -- where the newly single Cruise is known to spend some time.

Late last week, Katie Holmes filed for divorce from her husband of five years, and multiple news outlets are reporting that the actress ended her marriage in order to save their daughter, Suri, from being forced into Scientology.