Four or five years ago I wrote a novel, JUBILEE, in which a girl, Jessamy Winter, was abducted and then reappeared, safe, some years later. At the time I had some doubts, believing this might be unlikely, but it was important for the story I was writing that Jessamy turned up again. Research I carried out back then indicated that abducted children did sometimes reappear (Natascha Kampusch, for instance). 

Today I have just read the amazing story of the three young women in Cleveland kidnapped as teenagers, who have finally managed to free themselves. How wonderful for their families.