Case Details
- Citation: [2022] SGHC 170
- Title: Tiong Sze Yin Serene v Chan Herng Nieng
- Court: High Court of the Republic of Singapore (General Division)
- Suit No: Suit No 400 of 2020
- Date of Judgment: 19 July 2022
- Judges: Tan Siong Thye J
- Hearing Dates: 19–22, 26–28 April, 4 July 2022
- Judgment Reserved: Yes
- Plaintiff/Applicant: Tiong Sze Yin Serene
- Defendant/Respondent: Chan Herng Nieng
- Legal Areas: Tort — Negligence; Tort — Rule in Wilkinson v Downton
- Core Claims: Medical negligence (breach of duty of care); psychiatric harm under the rule in Wilkinson v Downton
- Key Factual Themes: Provision of Xanax (alprazolam) by psychiatrist to intimate partner without registering her as a patient; alleged psychiatric harm following discovery of infidelity and subsequent relationship breakdown; alleged intention to cause psychiatric harm
- Statutes Referenced (as indicated in metadata): Companies Act; Derivative Act (company in order to commence the Derivative Act); High Court with three Judges observed the SMC Ethical Code; Penal Code; Poisons Act; SMC Ethical Code; Schedule to the Poisons Act
- Other Statutory References (from extract): Poisons Act (Cap 234, 1999 Rev Ed); Penal Code (Cap 224, 2008 Rev Ed) — s 385 (attempted extortion)
- Drugs/Regulatory Context: Xanax (alprazolam) classified as a poisonous substance under the Schedule to the Poisons Act
- Related Proceedings Mentioned: SMC complaint; defamation suit (Ong Kian Peng Julian v Serene Tiong Sze Yin [2020] SGDC 94); derivative action suit (mentioned in judgment structure)
- Cases Cited (as provided): [2020] SGDC 94; [2020] SGHC 201; [2022] SGHC 170
- Length: 108 pages; 29,326 words
Summary
In Tiong Sze Yin Serene v Chan Herng Nieng [2022] SGHC 170, the High Court (Tan Siong Thye J) addressed claims brought by a former intimate partner against a psychiatrist. The plaintiff alleged that the defendant breached his duty of care by giving her Xanax (alprazolam), a controlled poisonous substance under the Poisons Act, without registering her as his patient. She further pleaded an alternative tortious route under the rule in Wilkinson v Downton, contending that the defendant had made statements about an exclusive long-term relationship and that his conduct caused her psychiatric harm.
The court’s analysis proceeded in two main stages: first, whether the defendant owed and breached a professional duty of care in relation to the provision of Xanax, and second, whether the elements of the Wilkinson rule were made out, including the mental element (intention) and the causative link to the psychiatric consequences. The judgment also reflects the court’s careful approach to credibility, professional standards, and causation in a dispute that arose from a highly personal relationship and subsequent retaliatory allegations.
What Were the Facts of This Case?
The plaintiff, Ms Tiong, met the defendant, Dr Chan, at a social event around 21 December 2016. At that time, Ms Tiong was still married, although her marriage was already in difficulty. She and Dr Chan began an intimate relationship in or around early January 2017. The relationship was generally smooth until April 2018, when it deteriorated rapidly after Ms Tiong discovered WhatsApp messages on Dr Chan’s mobile phone suggesting that Dr Chan had been unfaithful and engaged in sexual relations with other women, sometimes in groups.
After the discovery, Ms Tiong confronted Dr Chan with screenshots of the messages. The relationship then broke down irretrievably. As the defendant sought to end the relationship, Ms Tiong’s response escalated into demands for money and a Cartier watch, and she also sent the screenshots to Dr Chan’s family members. Dr Chan responded by making a police report against Ms Tiong for attempted extortion. The Singapore Police Force later issued Ms Tiong a written warning in lieu of prosecution for attempted extortion under s 385 of the Penal Code.
Against this backdrop, the plaintiff’s civil claim focused on the defendant’s earlier conduct during the relationship. She alleged that Dr Chan, a psychiatrist with more than 17 years’ practice, gave her Xanax tablets to help her cope with anxiety. Xanax (alprazolam) is listed as a poisonous substance under the Schedule to the Poisons Act. Importantly, the plaintiff’s case was that Dr Chan did not register her as his patient when he provided the medication. The evidence indicated that Dr Chan was in a position to procure Xanax from the Singapore General Hospital (SGH) by having a colleague, Associate Professor Lee Tih Shih, prescribe Xanax for him, after which Dr Chan gave the tablets to Ms Tiong.
Ms Tiong also alleged that she suffered side effects and became addicted to Xanax. In addition to the medical negligence claim, she pleaded that Dr Chan had told her he was committed to a long-term and exclusive sexual relationship, and that she later suffered a mental and emotional breakdown when she discovered his sexual relations with other women. The claim under Wilkinson v Downton thus sought to capture psychiatric harm allegedly caused by the defendant’s statements and conduct, framed as intentional infliction of mental distress.
What Were the Key Legal Issues?
The first key issue was whether Dr Chan owed Ms Tiong a duty of care in tort in relation to the provision of Xanax, and if so, whether he breached the applicable professional standard. This required the court to consider the general professional standard expected of a psychiatrist, including the relevance of the Singapore Medical Council’s Ethical Code and Ethical Guidelines, and whether those standards informed the content of the duty of care in a negligence claim.
The second key issue concerned causation and harm. Even if a breach were established, the court had to determine whether the plaintiff’s alleged psychiatric harm and losses were caused by the defendant’s conduct in providing Xanax, rather than by other intervening factors, including the emotional fallout from the relationship breakdown and the plaintiff’s subsequent actions and complaints.
The third issue was whether the plaintiff’s alternative claim under the rule in Wilkinson v Downton was made out. That rule requires, in substance, that the defendant (i) makes a statement or engages in conduct calculated to cause the claimant to suffer physical or mental harm, (ii) does so with the requisite mental element (classically intention to cause harm or recklessness as to causing harm), and (iii) the claimant suffers harm as a result. The court therefore had to assess the “conduct element”, the “mental element”, and the “consequence element” in the context of the parties’ competing narratives.
How Did the Court Analyse the Issues?
On medical negligence, the court began by identifying the applicable law and the professional standard governing a doctor’s conduct. The judgment emphasised that professional standards are not merely abstract ethical ideals; they can inform what a reasonable professional would do in the circumstances. The court examined the applicability of the SMC Ethical Code and Ethical Guidelines and then considered specific guideline provisions (as reflected in the judgment structure, including ECEG Guideline B1.5, B1.1, B1.4, C4, and B3). The analysis focused on whether Dr Chan’s conduct in prescribing and providing Xanax to Ms Tiong without registering her as a patient fell below the required standard.
The court also addressed the practical question of whether the defendant’s conduct amounted to a breach in the relevant sense. The plaintiff’s case was that Dr Chan failed to manage the medication responsibly, including by not treating her within a proper patient-doctor framework and by continuing or prescribing Xanax despite concerns. The judgment structure indicates that the court considered, among other matters, the “continued prescription of Xanax despite” a suicide attempt, and whether that supported a finding of breach. This part of the reasoning illustrates the court’s focus on clinical governance and safety: where a doctor provides a controlled substance, the standard of care includes appropriate assessment, documentation, and risk management.
In addition, the court considered the objectivity of a joint expert, reflecting that expert evidence played a significant role in determining both the professional standard and whether the defendant’s conduct was medically negligent. The judgment also analysed evidence on the frequency and quantity of Xanax given by Dr Chan. These factual findings were important because negligence in medication provision often turns on dosage, monitoring, and the appropriateness of continuing medication in light of the patient’s condition.
Having analysed breach, the court then turned to harm and causation. The plaintiff alleged side effects and addiction, but the court had to determine whether the psychiatric harm she claimed was attributable to the Xanax provision or to other causes. The judgment’s structure suggests that the court carefully assessed the plaintiff’s harm, the timeline of events, and the plausibility of causation. In disputes arising from intimate relationships, courts often confront the challenge of separating emotional distress caused by relationship dynamics from harm caused by medical treatment. The court’s approach reflects that causation must be established on the balance of probabilities, and that the presence of multiple stressors may weaken a direct causal narrative.
On the Wilkinson v Downton claim, the court applied the rule’s elements in a structured way. The judgment indicates that it analysed (1) the conduct element, (2) the mental element, and (3) the consequence element. The plaintiff’s theory relied on statements allegedly made by Dr Chan about exclusivity and long-term commitment, and on the later discovery of his infidelity. The court therefore had to decide whether the defendant’s conduct was of the kind that could be characterised as calculated to cause psychiatric harm, and whether the defendant possessed the requisite intention (or mental state) at the time of the conduct.
Crucially, the court’s reasoning also required an assessment of credibility and reliability. The judgment includes a section on “assessment of the witnesses”, with general observations regarding the plaintiff’s credibility and reliability, and separate observations regarding Dr Chan’s behaviour. These credibility findings likely influenced whether the court accepted the plaintiff’s account of what was said and intended, and whether the court found the mental element necessary for Wilkinson to be satisfied. Where a claim depends on alleged statements and alleged intent, the court’s evaluation of witness demeanour and consistency becomes central.
What Was the Outcome?
The provided extract does not include the court’s final orders. However, the judgment’s structure shows that the court reached conclusions on both the medical negligence claim and the Wilkinson v Downton claim, including specific “Conclusion on medical negligence claim” and “Conclusion on claim under the rule in Wilkinson”. In practice, the outcome would have turned on whether the plaintiff proved breach of duty, causation, and the requisite elements for intentional infliction of psychiatric harm.
For practitioners, the key takeaway is that the court treated the claims as distinct tortious pathways requiring separate proof: professional negligence demanded proof of duty, breach, and causation informed by medical standards; the Wilkinson claim demanded proof of intentional (or sufficiently culpable) conduct calculated to cause psychiatric harm, supported by credible evidence and a causal link to the consequences.
Why Does This Case Matter?
This decision is significant for lawyers and students because it illustrates how Singapore courts approach tort claims against medical professionals in the context of non-traditional doctor-patient relationships. The case raises the question of how far professional ethical standards and clinical governance principles translate into civil liability when a doctor provides medication to someone outside a formal patient registration framework. The court’s engagement with the SMC Ethical Code and Ethical Guidelines demonstrates that ethical guidance can be operationalised in negligence analysis, particularly where controlled substances are involved.
Second, the judgment is useful for understanding the evidential and causation challenges in psychiatric harm claims. Where the claimant’s distress is intertwined with relationship breakdown, allegations of revenge, and parallel complaints, courts must carefully evaluate whether the medical treatment is the legal cause of the harm. This is a recurring difficulty in negligence litigation involving mental injury: the claimant must show not only that harm occurred, but that it was caused by the defendant’s breach rather than by other events.
Third, the case provides a practical illustration of the Wilkinson v Downton rule’s mental element and evidential requirements. Psychiatric harm claims framed as intentional infliction of mental distress are not lightly made out. The court’s structured analysis of the conduct, mental, and consequence elements, together with its credibility assessments, underscores that plaintiffs must present clear evidence of the defendant’s culpable mental state and the causal connection to the psychiatric consequences.
Legislation Referenced
- Poisons Act (Cap 234, 1999 Rev Ed) — including the Schedule listing Xanax (alprazolam) as a poisonous substance
- Penal Code (Cap 224, 2008 Rev Ed) — s 385 (attempted extortion) (as referenced in the factual background)
- Companies Act (as indicated in metadata)
- Derivative Act (as indicated in metadata)
- High Court with three Judges observed the SMC Ethical Code (as indicated in metadata)
- Singapore Medical Council Ethical Code and Ethical Guidelines (as indicated in metadata)
Cases Cited
- [2020] SGDC 94
- [2020] SGHC 201
- [2022] SGHC 170
- Wilkinson v Downton [1897] 2 QB 57
Source Documents
This article analyses [2022] SGHC 170 for legal research and educational purposes. It does not constitute legal advice. Readers should consult the full judgment for the Court's complete reasoning.