Contextual “Life‑Sustaining Treatment” under s.89 ADM(C)A 2015: Jurisdiction, Interim Treatment, and Capacity as a Ground of AHD Invalidity

Case: Health Service Executive v MM (A Person Lacking Capacity Not So Found Represented By Her Guardian Ad Litem) and Anor (Approved)
Citation: [2026] IEHC 498  |  Court: High Court  |  Judge: Dignam J  |  Date: 22 July 2026

1. Introduction

This judgment is a leading early interpretation of the Assisted Decision‑Making (Capacity) Act 2015 (“the 2015 Act”) provisions on advance healthcare directives (“AHDs”), particularly the gateway concept of “life‑sustaining treatment” in s.89(2) (High Court jurisdiction) and the operation of s.89(3) (treatment pending determination).

The applicant (the HSE) brought proceedings concerning an adult patient (“Ms. M”) who was involuntarily detained under the Mental Health Act 2001 (“the 2001 Act”) during an acute manic episode. Ms. M had executed an AHD using the Decision Support Service template, stating she refused “any type of psychiatric medication” “in all circumstances,” and ticking the template option that the refusal should apply “even if my life is at risk because of this refusal.”

Although Ms. M was later discharged, the parties urged the Court to deliver judgment on issues with continuing significance. Dignam J elected to determine: (i) whether the application “involves considerations relating to life‑sustaining treatment” (and thus falls within s.89(2)); and (ii) whether lack of capacity at execution can render an AHD invalid, and whether Ms. M lacked such capacity in November 2025.

Key issues addressed

  • Meaning of “life‑sustaining treatment” (undefined in the 2015 Act) and its role in allocating jurisdiction between the Circuit Court (default) and the High Court (s.89(2)).
  • Whether psychiatric medication can be “life‑sustaining” on the facts (thereby engaging s.89(2) and enabling s.89(3) pending determination).
  • Whether lack of capacity at execution is a basis for invalidity, notwithstanding the definition of “valid” by reference to s.85.
  • Approach to interim orders in light of s.89(3) (self‑operating) and uncertainty about whether treatment qualifies as “life‑sustaining.”

2. Summary of the Judgment

  • Life‑sustaining treatment test: Dignam J set out a multi‑factor, context‑dependent approach. Treatment is “life‑sustaining” where it is proposed for the purpose of sustaining life and where withholding it “at that time” creates a real (not vague/notional) proximate risk of death.
  • Rejecting a “tick‑box” shortcut: The Court rejected the HSE’s submission that a directive-maker’s statement that refusal applies even if life is at risk automatically makes any s.89 application one involving life‑sustaining treatment.
  • Psychiatric medication on these facts: The Court held psychiatric medication was life‑sustaining in this particular case, due to the immediate cardiovascular risk profile arising from untreated mania combined with significant comorbidities and family history.
  • Capacity-based invalidity: Lack of capacity at execution is a ground on which an AHD may be declared invalid under s.89, despite the way “valid” is linked to s.85.
  • Outcome: A declaration issued under s.89(2) that the AHD executed on 6 November 2025 was not valid, because Ms. M lacked capacity at that time.

3. Analysis

3.1 Statutory framework and what was novel

The judgment sits at the intersection of:

  • Part 8 of the 2015 Act (AHDs): ss.82–86 (definition, formalities, validity/applicability, effect of refusals) and s.89 (court declarations; High Court carve‑out for life‑sustaining treatment; interim treatment under s.89(3)).
  • Guiding principles in s.8 (presumption of capacity; respect for autonomy and will/preferences; necessity and proportionality of interventions).
  • Code of Practice issued by the Director of the Decision Support Service: the Court treated it as relevant under s.91(14) (must be “taken into account” where relevant).

The novelty lay in the absence of prior written guidance on: (a) the meaning of “life‑sustaining treatment” for s.89(2)/(3); and (b) whether an AHD’s “validity” can be challenged for lack of capacity at execution where s.85(1) does not expressly list that ground.

3.2 Precedents cited and how they influenced the decision

(a) Statutory interpretation approach

  • Heather Hill Management Company CLG v An Bord Pleanála [2022] IESC 43 and A, B and C v Minister for Foreign Affairs and Trade [2023] IESC 10: relied upon for the modern synthesis—language, context, and purpose are always potentially in play, with the text as starting point but not the sole determinant.

(b) Existing AHD jurisprudence and the 2015 Act’s significance

  • The Child and Family Agency v KK [2024] IECA 242: cited for the characterisation of the 2015 Act as a profound shift in the legal regime governing vulnerable persons.
  • Governor of a Prison v XY [2023] IEHC 361: cited as the only other written Irish judgment considering Part 8 (in a different context), and for procedural handling (including in camera considerations).

(c) “Life-sustaining treatment” in earlier case law (contextual contrast)

The guardian ad litem invoked cases where courts proceeded on the basis that interventions such as ventilation, CPR, artificial nutrition/hydration, and cardiovascular supports were “life-sustaining,” including:

  • In the matter of JJ [2022] 3 IR 1
  • Re a Ward of Court (withholding of medical treatment) (No. 2) [1996] 2 IR 79
  • Re SR [2012] 1 IR 305
  • HSE v JM [2018] 1 IR 688
  • In the matter of SM [2025] IEHC 717

Dignam J held these authorities did not determine the statutory meaning in the 2015 Act, because they did not need to interpret the phrase and simply accepted the interventions as life‑sustaining on their facts. The Court thereby preserved conceptual space for treatments outside the “ICU‑type” paradigm to qualify as life‑sustaining where the statutory criteria are met.

(d) Handling expert evidence

  • C.D and B.B [2023] IEHC 204 (Stack J), drawing on Duffy v. McGee [2022] IECA 254, Donegal Investment Group Ltd. v. Danbywiske [2017] IESC 14, and Flynn v. Bus Éireann [2012] IEHC 398: cited for the proposition that even uncontroverted expert evidence need not be accepted; experts must explain reasoning and evidential foundations to enable judicial engagement.

This influenced the Court’s careful calibration of weight: substantial reliance on the treating psychiatrist’s evidence where reasons were articulated and linked to statutory tests, and limited weight to the independent report where factual inaccuracies and thin reasoning appeared.

(e) Capacity assessment in serious medical choices

  • Fitzpatrick v FK [2009] 2 IR 7 and Governor of X Prison v PMcD [2015] IEHC 259 (with reference to X.Y., A Minor v. H.S.E. [2013] 1 I.L.R.M. 305): used to support the notion that the gravity of refusing life‑sustaining treatment raises the evidential weight required to rebut capacity—while recognising the 2015 Act’s presumption of capacity changes the analytical starting point.

(f) Mental Health Act 2001 “treatment” (flagged, not decided)

  • HSE v MX [2012] 1 IR 81 and HSE v VF [2014] 3 IR 305, plus HSE v HH [2024] IEHC 564: discussed to show the uncertainty as to whether involuntary detention under the 2001 Act authorises non-consensual treatment for purely physical conditions unrelated to the mental disorder. Dignam J expressly left this for full argument in an appropriate future case.

3.3 Legal reasoning

(A) “Life‑sustaining treatment” under the 2015 Act: a cautious, context-based test

The Court held that because the Oireachtas did not define “life‑sustaining treatment,” the task is not to create an exhaustive definition but to provide an approach grounded in statutory purpose, structure, constitutional context, and practical medical realities.

Key reasoning steps:

  • No automatic “narrow” or “broad” presumption: autonomy and will/preferences (s.8; Part 8 purpose) counsel caution, but protection of life and the statutory choice of “life‑sustaining” (not merely “life‑saving”) counsel against setting the bar so high that valid life-protecting interim care becomes impossible.
  • Context and circumstances control: whether a treatment is life‑sustaining may vary with the patient’s clinical state and vulnerabilities (the Court adopted the “antibiotics” example to illustrate contingency).
  • Temporal/proximity requirement (“at that time”): anchored in s.89(3), the Court stressed that the risk must arise immediately/proximately/within a very short time if treatment is withheld—not merely at some indeterminate point in the future.
  • Risk need not be certain or “likely” death: the Act refers to life being “at risk” (s.85(3)); requiring certainty or probability would import words not chosen by the Oireachtas.
  • Rejecting the “tick-box” jurisdiction theory: jurisdiction cannot be triggered solely because a directive-maker stated the refusal applies even if life is at risk; otherwise routine disputes could be escalated to the High Court and s.89(3) would routinely neutralise AHD refusals contrary to Part 8’s objectives.

The Court ultimately distilled “life‑sustaining treatment” into a structured set of criteria, including:

  • the treatment must be proposed for the purpose of sustaining life;
  • withholding it must create a real (not vague/notional/general) risk of death;
  • the risk must arise from non‑provision “at that time,” immediately/proximately/within a very short time;
  • the assessment must be approached cautiously given the Circuit Court’s default jurisdiction.

(B) Psychiatric medication as “life‑sustaining” on these facts

A central doctrinal development is that psychiatric medication can qualify as life‑sustaining where evidence establishes a proximate risk of death without it. The Court accepted the treating psychiatrist’s evidence that untreated mania significantly elevates cardiovascular risk and premature death risk, and that this risk was intensified by:

  • the patient’s uncontrolled diabetes, hypertension, and raised cholesterol;
  • a significant family history of heart disease; and
  • clinical indicators (including concerning blood pressure readings and emerging risk of diabetic ketoacidosis in the contemporaneous period).

Crucially, the Court treated this as fact-sensitive, not a categorical rule that psychiatric treatment is generally life‑sustaining. It also rejected, “for completeness,” the proposition that risk of harm from potential retaliation by other patients was the kind of “risk of death” contemplated by the 2015 Act for this jurisdictional gateway.

(C) Interim orders and s.89(3): self-operating permission plus a “mandatory injunction”-type threshold for court-ordered relief

The judgment clarifies that s.89(3) is self‑operating: while awaiting the High Court’s decision in a s.89(2) case, the AHD does not prevent provision of life‑sustaining treatment or acts reasonably believed necessary to prevent serious deterioration.

However, because clinicians may face uncertainty or dispute about whether treatment is truly life‑sustaining, the Court anticipated applications for interlocutory orders in all but the clearest cases. Dignam J held the appropriate interlocutory standard should be analogous to a mandatory interlocutory injunction:

the applicant must show a strong case that the treatment is life-sustaining and that the AHD is invalid and/or inapplicable.

This is a notable attempt to balance (i) the autonomy/bodily integrity interests that AHDs protect with (ii) the right to life and the risk of irreversible harm if courts move too slowly.

(D) Capacity as a ground of AHD invalidity despite s.85’s text

A second major doctrinal holding is interpretive: although s.82 links “valid” to s.85, and s.85(1) lists two invalidity grounds (involuntariness; later inconsistent acts), the Court held this list is not exhaustive. The more fundamental eligibility requirements in s.84(1)—adult status and capacity—are inherent preconditions. Accordingly, an instrument purporting to be an AHD is invalid if made by:

  • a minor; or
  • an adult lacking capacity at execution.

The Court’s reasoning was driven by coherence and safeguarding function: if lack of capacity were not a ground of invalidity under s.89, then (paradoxically) s.89(3) would permit interim life‑protecting treatment where duress is alleged, but not where the maker lacked capacity or was a child—an outcome the Court regarded as untenable within the Act’s structure.

In the alternative, the Court signalled that if it were wrong on interpretation, this would amount to a legislative lacuna justifying recourse to the High Court’s inherent jurisdiction to protect constitutional rights pending determination.

(E) Applying the functional capacity test to an AHD executed in the past

The Court applied:

  • s.8(2) presumption of capacity (burden on the HSE);
  • s.3 functional test (understand, retain, use/weigh, communicate);
  • and the “gravity” lens from Fitzpatrick v FK and Governor of X Prison v PMcD, recognising that refusal of potentially life‑sustaining treatment demands a high degree of understanding (while still keeping the statutory presumption central).

The evidence was mixed: two lay witnesses present at signing considered Ms. M aware of what she was doing, but described her as “erratic,” “heightened,” “a little high,” and more “highly strung” after reducing medication. Family evidence described escalating manic features and a fixed refusal of medication even if life was at risk, accompanied by statements suggesting impaired appreciation of consequences (e.g., likening cessation effects to taking ecstasy). The treating psychiatrist gave a reasoned opinion linking the collateral history to impaired ability to understand and use/weigh relevant information.

Balancing these strands, Dignam J held the presumption of capacity was rebutted and Ms. M lacked capacity on 6 November 2025. The AHD was therefore declared invalid.

3.4 Impact

(1) Forum selection and litigation strategy under s.89

The decision supplies a workable test for whether proceedings “involve considerations relating to life‑sustaining treatment.” This matters because:

  • it determines whether the case belongs in the Circuit Court (s.89(1)) or High Court (s.89(2)); and
  • it determines whether the interim “override” mechanism in s.89(3) is available.

By rejecting an automatic rule based on the directive-maker’s “life at risk” statement, the Court reduces the scope for jurisdictional manipulation and preserves the Circuit Court’s default role.

(2) Clinical risk evidence becomes central to “life‑sustaining” classification

The judgment indicates that “life‑sustaining” will often turn on granular medical evidence of proximate risk, not on the category of treatment. This may expand the range of cases in which psychiatric (and other non‑ICU) interventions can be treated as “life‑sustaining,” but only where the evidential standard on immediacy and real risk is met.

(3) Strengthened capacity scrutiny for AHD execution

Because lack of capacity at execution is confirmed as a basis for invalidity, practitioners and healthcare professionals may place increased emphasis on:

  • contemporaneous documentation of capacity and voluntariness when AHDs are made;
  • the possibility of fluctuating capacity (particularly with episodic conditions); and
  • clear linkage between the refusal and an understanding of consequences.

(4) Interlocutory practice: “strong case” threshold

Although framed as guidance, the “mandatory injunction”-type threshold is likely to influence how hospitals frame evidence at the urgent stage—especially where they seek court comfort in contested s.89(3) scenarios.

(5) Open questions left for future litigation

The judgment explicitly left undecided:

  • the applicability of this AHD (fact-specific, and unnecessary after discharge); and
  • the scope of “treatment” under the Mental Health Act 2001 as regards non-consensual treatment for physical comorbidities unrelated to the mental disorder.

4. Complex Concepts Simplified

  • Validity vs applicability (2015 Act): an AHD may be valid (properly made) but not applicable (e.g., the person still has capacity; the treatment/circumstances are not materially the same). This judgment decided validity only.
  • Functional capacity (s.3): capacity is decision-specific and time-specific; the question is whether the person can understand, retain, use/weigh relevant information, and communicate a choice.
  • “Life‑sustaining” is not “life‑saving”: the Act’s language (“life at risk”) allows for real, proximate risk without requiring certainty that death will follow if treatment is withheld.
  • Why jurisdiction matters: only High Court cases under s.89(2) engage s.89(3), which temporarily prevents the AHD from blocking life‑sustaining treatment while the court decides.

5. Conclusion

Dignam J’s decision in [2026] IEHC 498 establishes two important interpretive guideposts for Part 8 of the 2015 Act: first, a cautious but practical, evidence-led framework for deciding when treatment is “life‑sustaining” for s.89(2)/(3); second, confirmation that lack of capacity at the time of execution is a ground of AHD invalidity notwithstanding s.85’s enumerated invalidity factors. The case also signals an approach to urgent interim applications that aims to respect AHD autonomy while safeguarding life where proximate risk is credibly established.