                district court's sound discretion, and this court will not disturb the district
                court's custody decision absent a clear abuse of that discretion.     Castle v.

                Simmons, 120 Nev. 98, 101, 86 P.3d 1042, 1045 (2004); Wallace v. Wallace,
                112 Nev. 1015, 1019, 922 P.2d 541, 543 (1996).
                            We agree with appellant that a custody modification must be
                based on the child's best interest and not to punish a parent for
                misconduct. See Dagher v. Dagher, 103 Nev. 26, 28, 731 P.2d 1329, 1330
                (1987); see also Sims v. Sims,      109 Nev. 1146, 865 P.2d 328 (1993).
                Nevertheless, it is clear from the record that the district court thoroughly
                considered each of appellant's arguments and declined to modify custody
                because a modification was not in the child's best interest. The district
                court specifically found that the child had been thriving under the parties'
                joint custody agreement and that appellant had not established that
                respondent's mental health condition affected his ability to parent. The
                court further found that respondent had rebutted the domestic violence
                presumption against joint custody. NRS 125C.230(1). It is the duty of the
                trier of fact, not an appellate court, to weigh the credibility of witnesses.
                Castle, 120 Nev. at 103, 86 P.3d at 1046.
                            As for the substance abuse issue, the district court found that
                respondent did have alcohol problems, but declined to modify custody on
                this basis and instead ordered respondent to refrain from using alcohol or
                drugs during or within 24 hours before his custodial time. Therefore, the
                district court did address respondent's substance abuse issue as it affected
                the child's best interest. We conclude, based on the totality of the record,




SUPREME COURT
        OF
     NEVADA1


(0) 1947A
                that the district court did not abuse its discretion in denying appellant's
                motion to modify custody. Id. at 101, 86 P.3d at 1045. Accordingly, we
                            ORDER the judgment of the district court AFFIRMED.'




                                                             Hardesty

                                                               b.ot
                                                             Parraguirre


                                                                                           J.
                                                             Cherry



                cc: Hon. Kenneth E. Pollock, District Judge
                     Robert E. Gaston, Settlement Judge
                     Dickerson Law Group
                     Sterling Law, LLC
                     Eighth District Court Clerk




                       'In light of our disposition, we deny as moot respondent's request for
                a status check.



SUPREME COURT
        OF
     NEVADA


(0) 1947A
