Prosecutors declined to comment.
Colorado law defines insanity as the inability to distinguish right from wrong, caused by a diseased or defective mind. The law specifically excludes depravity, "moral obliquity" and passion caused by anger, hatred or other emotions from being considered insanity.
Prosecutors say Holmes, 25, spent months buying guns and thousands of rounds of ammunition, donned police-style body armor and opened fire during a midnight screening of the latest Batman movie.
Last month, prosecutors filed a court document listing aggravating factors they plan to raise in a possible death penalty phase of the trial. The factors included the death of 6-year-old Veronica Moser-Sullivan, the youngest of dead.
Prosecutors also said in the filing that the slayings were "especially heinous, cruel or depraved."