Is a witness's drug use relevant to credibility?

^35. To the extent the trial court may have erroneously believed a witness's drug use is always relevant to credibility, "'"[n]o rule of decision is better or more firmly established by authority, nor one resting upon a sounder basis of reason and propriety, than that a ruling or decision, itself correct in law, will not be disturbed on appeal merely because given for the wrong reason. If right upon any theory of the law applicable to the case, it must be sustained regardless of the considerations which may have moved the trial court to its conclusion."' [Citation.]" (People v. Brown (2004) 33 Cal.4th 892, 901.)