As people we are very social when it comes to talking to other people. This technique is hiding us from that which can make people go crazy and go into deep thinking. This technique thus can be quite effective when it comes to making people talk about things they didn't want to talk about.
I don not believe that this would be efficient in getting information out of a prisoner. For this to work a prisoner would have to be isolated for a very long period of time and normally by then the information they had that was of any valuable is not and has probably changed. I believe that there are more efficient ways that we can interrogate to obtain information.