Can a defendant challenge the credibility of a witness on the Page 17?

"[T]he mental illness or emotional instability of a witness can be relevant on the issue of credibility, and a witness may be cross-examined on that subject, if such illness affects the witness's ability to perceive, recall or describe the events in question." (People v. Gurule (2002) 28 Cal.4th 557, 591-592.) A defendant may challenge the credibility of a declarant on the

Page 17

same bases as the credibility of a witness. (People v. Blacksher (2011) 52 Cal.4th 769, 806 (Blacksher).) The trial court has "broad discretion" to determine whether to admit such evidence. (People v. Herring (1993) 20 Cal.App.4th 1066, 1072.) "On appeal, a trial court's decision to admit or not admit evidence . . . is reviewed only for abuse of discretion." (People v. Williams (1997) 16 Cal.4th 153, 196-197.)