Professor Mearns said an emerging counselling service was being developed in three west of Scotland secondaries but one youngster had told him: "If it's not confidential, forget it."
Guidance staff often made referrals to the counsellor who ran around eight meetings a day with pupils. That still left waiting lists in each school.
Professor Mearns stressed that counselling services had to be "in the school but not of the school".
Annie Baikie, an Aberdeen children and adolescent psychotherapist, said: "Confidentiality is important but child protection is paramount."