The following excerpt is from Catholic Children’s Aid Society of Metropolitan Toronto v. M.M., 1981 CanLII 1975 (ON CJ):
 The record in this case is not yet complete but, with the above considerations in the background, I have examined the 83 documents that were tendered with a view to responding to counsel’s submissions on the possibility of a probative value beyond the limitations under section 36 of the Ontario Evidence Act. Realizing that counsel may wish to make further submissions when the record is complete, I am prepared to make some comments now with the hope of responding to numerous questions raised in argument: (1) The 83 documents tendered contain opinions, impressions and diagnoses written by 28 different doctors and 11 different nurses. This is a good argument on the grounds of necessity for considering a reasonable alternative to the calling of all 39 witnesses in court. (2) In so far as the opinions, impressions and diagnoses spanning 28 doctors, 11 nurses, 7 agencies and approximately 4 years, are consistent, there is an accumulative effect that provides an operative element of trustworthiness. At some point, a tactical onus of proof may shift to the patient to promote the notion that all of the opinions, impressions and diagnoses grew from a common root of misconceptions. (3) The professionals working in the seven agencies here are unlikely to be motivated to mislead (except, perhaps, with regard to the documents relating to involuntary admission which contain a self-serving feature that invites caution) and this is an operative element of trustworthiness. (4) Writings containing opinions, impressions or diagnoses where the author of the writings cannot be identified by name are unreliable and should be given no weight. (5) As opinions and impressions move from fairly straightforward observations such as the “blue toes” in Ares v. Venner into the more esoteric realm of psychiatry, the readiness to attach significant weight should be more restrained. (6) Having particular regard to the imperfect state of the science of psychiatry, I do not think opinions, impressions, or diagnoses of a psychiatric nature generally lend themselves well to proof through the filing of hospital records. (7) Where the source of a “history” (or parts of it) is clearly the patient herself, there is an operative element of trustworthiness when the history is tendered by the opposing party. But wherever the source is not clarified, the history is unreliable. (See Setak below).