The association said it was considering proposals to prohibit psychologists from participating in interrogations and to modify its ethics policies, among other changes.

The involvement of psychologists in the interrogation programs has been a source of contention within the profession for years. Another report, issued in April by several critics of the association, came to similar conclusions. But Mr. Hoffman’s report is by far the most detailed look yet into the crucial roles played by behavioral scientists, especially top officials at the American Psychological Association and some of the most prominent figures in the profession, in the interrogation programs. It also shows that the collaboration was much more extensive than was previously known.

A report last December by the Senate Intelligence Committee detailed the brutality of some of the C.I.A.’s interrogation methods, but by focusing on the role of psychologists, Mr. Hoffman’s report provides new details, and can be seen as a companion to the Senate report.

The C.I.A. and the Pentagon both conducted harsh interrogations during the administration of President George W. Bush, although the C.I.A.’s program included more brutal tactics. Some of them, like the simulated drowning technique called waterboarding, are now widely regarded as torture. The agency’s interrogations were done at so-called black site prisons around the world where prisoners were held secretly for years.

The report found that while some prominent psychologists collaborated with C.I.A. officials in ways that aided the agency’s interrogation program, the American Psychological Association and its staff members focused more on working with the Pentagon, with which the association has long had strong ties.

Indeed, the report said that senior officials of the association had “colluded” with senior Defense Department officials to make certain that the association’s ethics rules did not hinder the ability of psychologists to remain involved with the interrogation program.