In Ballard v. Superior Court (1966) 64 Cal.2d 159, the Supreme Court held that a trial court has discretion to order the complaining witness in a case involving sex violations to submit to a psychiatric examination "if the circumstances indicate a necessity for an examination. Such necessity would generally arise only if little or no corroboration supported the charge and if the defense raised the issue of the effect of the complaining witness' mental or emotional condition upon her veracity." ( Id., at pp. 176-177.)