So, the sectarian movements raised from the 20th century a specific profile. Indeed, at the beginning, they only were groups of people with a doctrine religious marginal, in relation to an “official” religion. However, nowadays, the word “sect” is derogatory and defines a religious group with a more or less malicious behavior : the guru manipulates his followers and deprives them from their freedom and properties. Moreover, most of the time, the main goal of a sect is to extort money from people with problems.
Ethymologically, the word “sect” comes from the Latin “sequi” which means “follow” (but some people think “sect” is from the latin “secare”, so “cut” in english). Furthermore, in Greek, this word is equivalent to “hairesis”, which means “heresy” : a doctrine against the ideas transmitted by a religion. Knowing that to the catholics, a heresy has got a pejorative connotation : it's a dissident doctrine. In this way, according to the time, those groups are considered otherwise. And indeed, nowadays, we usually call them “sects”.
Then, from the sociological point of view, the sect brought people together by a same religious or philosophical ideal, those people are generally dropouts and who feel forced by a mission.
Furthermore, in the 19th and 20th centuries, sociologists and theologists as Max Weber or Ernst Troelstch gave their own definitions of the word “sect” : an extremist religious group, hard-nosed with their members and opposed to the society.
But of course, the sects do not define themselves as the previous definitions that we gave. Indeed, they present themselves as a new religion or association which wants to “teach” love, science, or otherwise their own beliefs. According to them, their members can get thanks to their help, a personal development and reach happiness.
Therefore, we can become aware that the word “sect” is more or less ambivalent, because it was described in the history as a religious group which broke away from a “certified” religion, and nowadays, it has a pejorative connotation : it's a group who disagrees with the society, and it aims at attracting people in order to manipulate them. But indeed, there is no really unbiased.
Finally, you have to know that the sects are numerous and varied throughout their doctrines, their members, and their organisation. Nevertheless, we can notice two large types of sects : pantheist and monotheistic.
The monotheistic ones are usually the least dangerous. This type of sect recruits in the popular class. Moreover, the members do an intense proselytism, frequently dressed with a “recognizable” uniform. Be careful : they can be persuasive in a very easy way.. The best example is the Jehovah's Witnesses.
The pantheist ones are more subtle. Indeed, behind their “cool”, tolerant and open looks, hide a totalitarian system. Unlike the monotheistic sects, they recruit in the comfortable class, usually through psychoterapies, or also yoga classes, formations of personal development, etc..
Now that the definition of the word “sect” is more clear, we are going to give you some criterions which will allow you to recognize a sectarian movement (but don't forget that all the differents groups from a “certificate” religion are not necessarily sectarian) :
▬ presence of a “guru”, a person who has got the absolute power, a spiritual leader
▬ social rupture, especially with your relatives
▬ mental manipulation, the person becomes psychologically fragile
▬ financial demand
▬ pression and threats
▬ antisocial speech