See [
www.culteducation.com]
Psychiatrist Robert Jay Lifton, who wrote the definitive book about thought reform (often called "brainwashing") also wrote a paper about cult formation. Lifton defined a cult as having the following three characteristics:
1. A charismatic leader, who increasingly becomes an object of worship as the general principles that may have originally sustained the group lose power.
2. A process [is in use] call[ed] coercive persuasion or thought reform.
3. Economic, sexual, and other exploitation of group members by the leader and the ruling coterie.
Some groups once seen as "cults" often move more into the mainstream, becoming generally respected sects or religions.
There are certainly examples of groups that were once perhaps thought of as "cults" that have evolved into relatively mainstream sects or religions. Such examples as the Seventh Day Adventists once led by Ellen White, or the Mormons, also known as the Church of Jesus Christ of the Latter Day Saints.
But it is also important to note that some groups, which may have once been labeled as "cults" continue to be controversial due to their unsafe or destructive practices. Two examples of groups that continue to be problematic and often destructive are the former Russellites, now known as "Jehovah's Witnesses," that once prohibited organ transplants and still expects its members to refuse blood transfusions, which has resulted in numerous deaths. And the Christian Scientists founded by Mary Baker Eddy who often reject medical treatment, again resulting in the loss of life. Some groups may say they have renounced unsafe or destructive practices, only to be exposed later as guilty of the same extremes and abuses.