If the websites complied, the suit would be withdrawn, he said, adding there was a need for the contents to remain private.
"We are concerned that the test responses are not valid when there has been prior exposure," the attorney said.
If participants had seen the contents before taking part their responses could be of questionable validity, he told Minnesota Public Radio (MPR) News.
The test, known as MMPI, developed at the University of Minnesota to assess personality traits and help diagnose mental disorders, presents participants with more than 500 true-false statements. The test is said to be one of the most-used psychological tests in the US.
Yesterday in Napier, establishing a base in an Emerson St office, Mr Dobson told Hawke's Bay Today he originally downloaded the test from a free-for-use website, but had it removed when he was satisfied the university had established its rights.
MPRNews says one of the websites (www.hypnoticmp3.com) posted an unsigned statement saying: "I appreciate the hundreds of emails from psychologists, students, university personnel and members of the public interested in the test. I will continue to provide a list of my products I believe will help you normalise your score with the MMPI but for now unable to offer the test itself."
Mr Dobson became interested in the subjects years ago while in the town of Glastonbury on his OE and returned to New Zealand to study at Massey and Otago universities, obtaining a BSc (psychology) and a DipSci (psychology) along with other qualifications through other institutions, including a diploma in clinical hypnotherapy.