A Ph.D. in I/O can look a lot more like a Ph.D. in Statistics and a lot less like an (Applied) Psych Ph.D....depending on the program. It is a far far different animal than even a research-heavy Clinical/Counseling Psychology Ph.D. The type of classes and thrust of the program will have a thread of psychology in it, but the learning and application of knowledge will be quite different.
In a typical I/O position you have business clients and not patients. Your work is much more about analyzing the type of jobs/employees a company utilizes, and not helping them through a divorce or substance abuse issue. I'd encourage you to talk to people in the I/O field because it is quite diverse, but there is very little, if any, overlap into Clinical/Counseling Psychology.