Members of NA are encouraged to abstain from using all forms of drugs, including alcohol. The group has the opinion that complete abstinence makes it easier for its members to make the personal changes necessary to sustain their recovery. The exception to this policy is when psychiatric or other medications have been prescribed by a physician and used according to directions. Effectiveness: Does Narcotics Anonymous Work? According to the NA web site, a survey of its members indicated that they had a mean number of 9.1 years clean. The results of the 2007 survey also revealed that 90 percent of the organization's members felt their lives were richer after seeking help from the group. In addition, 83 percent felt a stronger sense of social connections after joining. Controversy and CriticismDifferent groups had their own opinions about the content contained in the book put out by NA, which led to some internal controversy. In 1988, the NA World Conference made a determination that the 5th Edition of the group's text is the only one that is officially approved for distribution and sale.