Thus Sprach Experts

In the criminal law of Hong Kong, there remain strict and complex rules against hearsay evidence, which involves a person repeating what they have heard from others. Governed by intricate rules and numerous exceptions, the issue of hearsay evidence has routinely drawn the attention of appellate courts in recent years.

In HKSAR v Li Cheung Choi (李長再) [2025] HKCFA 1, the Court of Final Appeal considered what a patient told a psychiatrist after the event, the admissibility of those out-of-court statements, and the doctor’s expert opinion in a murder trial. The appellant strangled his wife with a belt in a taxi in the Tate’s Cairn Tunnel. He did not dispute the killing but admitted to manslaughter by diminished responsibility under section 3(1) of the Homicide Ordinance (Cap 339), on the footing of stimulant psychosis. But he did not give evidence in court. His case depended, in material part, on what he had later told Dr Choi about hallucinations and delusions at the time of the killing. Prosecution psychiatrists, to whom he had given a different history, disagreed.

The trial judge directed the jury that those statements were hearsay if used to prove their truth, but admissible to show the basis of Dr Choi’s opinion, the weight of which was for the jury. The Court of Appeal upheld the conviction and the direction. It nonetheless exceptionally suggested law reform to address a patient-doctor hearsay situation by analogy with mixed statements. That the history given to the expert might be treated as evidence of its truth, subject to a warning on weight.

However, the invitation was rejected by the CFA, which maintained that any new exceptions to the hearsay rules should be undertaken through legislation. There is nothing so unique in the doctor-patient interview, and a jury cannot properly weigh an untested assertion as if it were sworn fact.

That does not empty the expert report. If the statements are received only to show what was said to the expert but not the truth, the hearsay rule is not infringed. It is rare that a psychiatric opinion rests solely on the accused’s unsworn account. Where the opinion is also founded on admitted or independently proved facts, the opinion goes in, and the rest is a matter of weight. The appeal was unanimously dismissed.

What the patient told the doctor is not, without more, proof that it happened. It may still go before the jury as the basis of the opinion. Reform of this corner of hearsay may be necessary, but it will have to come by legislation.