What kind of short- and/or long-term harm do you think the participants in this

What kind of short- and/or long-term harm do you think the participants in this study could have experienced?
If you were a researcher conducting a similar study, how would you do it more ethically? Please include details on what you would change about the prison study.
Because parts of this study are considered unethical, do you think that using the results of the study to help researchers understand human behavior is also unethical? Why or why not?