There have been a number of cases in the recent past which talk about people being found who have been confined to their homes, some for sexual purposes by their own family members, for many many years. Each other such a case is found, there is always a great amount of surprise, as to how such a thing can happen.
In yet another case, a woman was locked up in a house for over 20 years, and this was only recently discovered when police arrived for a raid, and found the lady calling for help (link to article):
Police in Brazil said they had freed a 45-year-old woman who had been locked in a house for 20 years with no communication with the outside world.
Police in the state of Parana yesterday said that the woman was locked in the home by her partner, a 60-year-old man, in the city of Mariluz, 550 kilometers (340 miles) from the state capital Curitiba.
In the complaint, "the assistant told the police that a person was kept imprisoned for 20 years and was going through health problems, since she was banned from medical supervision," said Viana.