The butterfly effect – where is the line with causation?

**Trigger warning: This article discusses topics related to death and suicide. Reader discretion is advised.**

This article delves into the complexities surrounding entitlement to compensation in cases involving psychiatric injury, and the challenges that arise when the consequences of a psychiatric injury are wider reaching than initially envisaged. 

Culhana v State of New South Wales

Mr Stockwell was employed as a police officer by the State of New South Wales. In the course of his employment with the State, Mr Stockwell sustained a psychological injury as a result of struggling with recent jobs involving suicide. Liability to pay workers compensation for the psychological claim was accepted by the State.

Two years later, Mr Stockwell was subsequently diagnosed with Barrett’s oesophagus and adenocarcinoma. Liability to pay compensation for this injury was disputed. On 27 November 2022, Mr Stockwell died as a result of metastatic gastroesophageal functional carcinoma. 

1. The New South Wales Personal Injury Commission [1] was asked to determine the following questions: Whether Mr Stockwell’s Barrett’s oesophagus and adenocarcinoma resulted from the psychological injury deemed to have occurred in November 2019; and
2. Whether Mr Stockwell’s death resulted from the psychological injury deemed to have occurred in November 2019 pursuant to section 25(1) of the Workers Compensation Act 1987. 

The Commission confirmed that causation is not always direct and immediate. [2]

Taking into consideration all factual and medical evidence, the Commission ruled that that Mr Stockwell’s death was in fact as a result of his psychological injury sustained at work. Accordingly, the State was liable to pay compensation in respect of the death pursuant to sections 25 and 26 of the Workers Compensation Act 1987. 

His Honour focused his attention on: 

1. Causal chain evaluation: The Court took a common sense evaluation of the causal link between the work-related incident and subsequent injuries or death. Emphasis was made on the fact that mere temporal proximity between incidents does not alone determine compensation entitlement. 
2. Fact-based causation: Determining causation requires thorough examination of factual evidence and expert opinions regarding the link between the injury and subsequent medical conditions.
3. Substantial contribution: There must be evidence that the work injury has materially contributed to the subsequent conditions leading to death, rather than being the sole or primary cause.

Evidence presented in court demonstrated that Mr. Stockwell's PTSD symptoms, exacerbated by his job stress, led to increased stomach acid secretion, causing gastroesophageal reflux disease (GORD) and eventually Barrett’s oesophagus. His coping mechanisms included heavy alcohol and tobacco use, to relieve his symptoms of anxiety and PTSD, further aggravated these conditions.

Key takeaway

The legal principle derived from this case is that an applicant need not prove the injury was the primary cause of subsequent conditions leading to death, but rather that it materially contributed to them.

This decision highlights how workplace psychological injuries can significantly impact physical health, and vice versa, and underscores the need for insurance providers to recognize and address these interconnections.

The approach is consistent with other recent decisions in other jurisdictions involving complex causal chains such as: 

• A worker sustained a penetrating eye injury in the course of their employment and lost his sight in one eye. He developed an adjustment disorder and suicidal ideation, and as a result of that secondary psychiatric condition, deliberately drove his car in a manner intended to end his life. He sustained catastrophic (but not fatal) injuries in the accident, and those catastrophic injuries were found to be compensable by his employer: Bartemucci v Return to Work Corporation of South Australia [2023] SAET 51
• A worker sustained PTSD and depression as a result of witnessing traumatic incidents at work.  The worker subsequently died after ingesting an illicit drug commonly used recreationally. It was unclear whether the death was caused by suicide or by accidental overdose. The Tribunal found that the worker’s death was caused by the worker using the illicit drugs to self-medicate, and that it was either an attempt to die by suicide or he was reckless as to the consequences, and in either case his death was compensable: Muir v Department for Correctional Services [2022] SAET 68

[1] Culhana v State of New South Wales (NSW Police Force) & Ors [2024] NSWPIC 257 (May 17, 2024),

[2] Kooragang Cement Pty Ltd v Bates [461]. 

This article was written by Moashka Audit, Solicitor Insurance & Risk.