In People v. Pertz, 242 Ill. App. 3d 864, 900, 610 N.E.2d 1321, 1344, 183 Ill. Dec. 77 (1993), the doctor's expert opinion regarding the defendant's honesty during interviews conducted by the doctor was held to be inadmissible because the doctor's testimony would have lent his professional credibility to the defendant's statements, unfairly affecting the credibility of the case. Pertz, 242 Ill. App. 3d at 900, 610 N.E.2d at 1344-45. Thus, the expert witness in Pertz offered testimony regarding a defendant's honesty during the interviews.