It is pretty much like orginal conversion to Jesus Christ as Saviour and Lord. The Bible teaches:
Mt 10:34 Think not that I am come to send peace on earth: I came not to send peace, but a sword.
35 For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law.
36 And a manís foes shall be they of his own household.
37 He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me.
38 And he that taketh not his cross, and followeth after me, is not worthy of me.
Leaving a cult is traumatic in most cases. If the whole family does not leave, the family will be split and the exiting members shunned. Shunning is a good indication that the group is cultish no matter how biblical their preaching may be.
Then there is the psychological tearing of the fabric of the former cult member's belief system. This process is graphically and beautifully illustrated in the series of videos on this page. A former Mormon's quest for truth.