When insanity is presented as a defense in a civil case, is the trial judge free to consider all possibly relevant evidence?

When insanity is presented as a defense, "the trial judge should be free in his admission of all possibly relevant evidence." United States v. Hartfield, 513 F.3d 254, 260 (9th Cir. 1975). . . . Possibly relevant evidence includes evidence of the defendant's mental condition over a period of time. "(S)ince conditions of mental disease are more or less continuous, '(i)t is therefore proper, in order to ascertain * * * (the existence of mental disease) at a certain time, to consider its existence at a prior or subsequent time.' " United States v. Alden, 476 F.2d 378, 383 (7th Cir. 1973), quoting II Wigmore on Evidence 233, at 25 (3d ed. 1940).