Jemima Khan has done an interview with Eva Schloss in the New Statesman. For her, telling and retelling the story has been helpful. Ken Livingstone was the person who asked her to speak and she did. Before then she hadn't spoken to anyone.
My French great aunt wrote several pages about her time in Ravensbruck, near Berlin. As far as I know this was near the end of her life, so in the late 1990's. I was sent a copy, which I read. My French grandmother or my great aunt told me that after liberation and time in Sweden the two sisters spent several days in their parents' flat in Paris. They slept in the bedroom they had shared as children and just talked and talked. So maybe my great aunt was able to process it out of her system more easily in part due to this listening time.
There is a hashtag going on for Bahrain at the moment, #eye4freedom. One tweet states that the person concerned, Jaffar Salman, was not able to speak of his experiences to anyone apart from one fellow prisoner.
In the US a now freed death row inmate, Anthony Graves, has been explaining to Senators what solitary means, putting into words sights he has seen, witnessing to others' pain as well as his own.