What were the long-term effects on the participants of the Stanford Prison Experiment? It has been maintained by Dr. Philip Zimbardo that the experiment has had no long-term harm on the participants. However, one out of the 24 initial participants, who had suffered a breakdown within 36 hours of starting, later went on to become a prison psychologist and has been in the profession for at least 14 years.

While the experiment may not have had any "harm" on the participants, the fact that it had such a huge impact on one participant (as the person himself claims in the experiment documentary), calls into question the fact that how much did the experiment end up altering or affecting the participant's lives. 

So, were long term effects (not just "harm") of the experiment tracked and documented by the team or anybody else? If tracked, has this been published at any point of time?

Secondly, in most of the popular literature and even on the official website, I do not find any discussion of the experiment in terms of long term effects. Are long-term effects of psychological studies on participants' not considered worth recording? Why?
I found this snippet from Quora: Whatever happened to the participants in the Stanford Prison Experiment? 

"They performed extensive follow-ups by bringing all the subjects back individually or in groups over a period of the first year and then for the next ten years they have surveyed them by mail and phone and the consensus is that they did suffer during that week of the experiment, but they learned a great deal about themselves and about human nature that most of them say was quite valuable."

Perhaps within the first decade after the experiment they found constancy in how the participants were affected and felt there was no longer a need for further analysis / recording.