Decision No. 693/20: Vice Chair Endeavours to Provide Adjudicative Framework for Chronic Mental Stress Entitlement

  • July 03, 2021
  • Julie Weller and Tristan Hunter, Mathews Dinsdale

WSIAT Decision No. 693/20 is the first WSIAT decision that provides a framework for adjudicating claims for Chronic Mental Stress (“CMS”) entitlement since coverage was expanded to this form of psychological entitlement as of January 1, 2018. Importantly, The Vice Chair provides an analysis of WSIB Policy No. 15-03-14 (the “CMS Policy”) whether a work-related stressor(s) is ‘substantial’ and whether the stressor(s) was the predominant cause of a worker’s mental stress injury. 

Interestingly, the case was decided by a sole Vice Chair (M. Crystal) and facts before the Vice Chair did not require them to consider each CMS entitlement criteria. The appeal was denied on the basis that the work-related stressors fell within the exclusion criteria outlined in ss. 13(5) of the Workplace Safety and Insurance Act (“WSIA”). The Vice Chair’s decision to provide a framework despite not needing to suggests their recognition that workplace parties have been waiting for further guidance. Although the Vice Chair may have set out to provide clarity, the decision raises new questions as to how the Policy will be applied. 


The accident employer is a community-based provider of home support services. The worker was hired in 2006 as a social worker. The employer considered the worker to be a solid contributor to the employer’s work. In 2017 the employer offered the worker a position as a Care Navigator. The worker understood that the position was part of a pilot project and agreed to take on the new challenge. 

Prior to transitioning into the new role, the worker began to feel apprehensive about the position and asked the employer for a written job description. Upon receiving the description, the worker was shocked to learn that the position was classified as a secondment and not as a permanent position. 

The worker immediately began to worry about their status with the employer, fearing for their job security. Shortly after learning that they were transitioning to a secondment, the worker began to experience insomnia, mood changes, loss of appetite, periods of crying, and general feelings of exhaustion. As the transition to the secondment neared, the worker began to feel depressed and anxious.

The worker had a history of anxiety and depression, for which they had received treatment prior to their employment with the Company. They had also experienced panic attacks. The worker took medication for their psychological conditions and the conditions were well-managed and under control until the incident at issue. As a result of their mounting depression and anxiety, the worker stopped working in January 2018. The worker then sought entitlement to benefits under the WSIA, claiming CMS caused by their employment. 


Ultimately, the Vice Chair held that the worker was not entitled to benefits for CMS on the basis that the work-related stressors were associated with the employer’s administration of the employment relationship. This is the exception to entitlement listed under ss. 13(5) of the WSIA. 

However, instead of limiting their decision to an analysis of how the work-related stressors were non-compensable, the Vice Chair also provided a detailed framework for CMS adjudication and an analysis of whether the identified events satisfied each of the CMS entitlement criteria. 

The Vice Chair provided the following adjudicative framework required for conducting an assessment regarding CMS at paragraph 35:

A worker who sustains an impairment related to chronic mental stress arising out of and in the course of employment is entitled to benefits for the impairment, subject to the following exceptions:

  1. Entitlement will not be in order if the work-related stressor(s) are not substantial;
  2. Entitlement will not be in order if the work-related stressor(s) are not the predominant cause of the impairment; and
  3. Entitlement will not be in order if the impairment is related to good faith actions taken by the employer in carrying out its role in the employment relationship. 

The analysis further included a breakdown of why the worker’s impairment was appropriately diagnosed and how identifiable events arose out of and in the course of employment. Of particular interest, the Vice Chair evaluated whether the worker’s work-related stressors were substantial in nature and whether the worker’s work-related stress met the ‘predominant cause’ test. 

1.     Was the Worker’s Mental Stress Injury Caused by a ‘Substantial’ Work-Related Stressor?

The Vice Chair held that the identifiable events qualified as substantial work-related stressors.

In the CMS Policy, the WSIB states that a work-related stressor will generally be considered substantial if it is excessive in intensity and/or duration in comparison to the normal pressures and tensions experienced by workers in similar circumstances. The Vice Chair concluded that the determination of whether a work-related stressor is substantial requires objective and subjective considerations.

  (i)    Objective Consideration: Average Worker Test

To determine whether the work-related stressor is objectively substantial, the Vice Chair applied the “Average Worker Test” (“AWT”). The AWT requires a decision maker to determine whether a worker of average mental stability would reasonably perceive the workplace events to be mentally stressful. If so, whether such worker would be at risk of suffering a disabling mental reaction to such perception. If the answer to either question is “no”, the psychological damage would not be compensable. 

The Vice Chair stated that the value of the AWT is to ensure that there is an actual injuring process associated with the employment and that the injury was not a function of an “atypical dysfunctional process in the worker’s mind’” (para 56). The Vice Chair stated that the nature of the accident or injuring process must be considered in light of the personal characteristics and vulnerabilities of an average person, rather than of the worker in question. 

(ii)    Subjective Consideration: “Thin Skull Rule”

The Vice Chair noted that the CMS Policy requires the decision maker to maintain the ‘thin skull rule.’  If, through the application of the AWT the decision-maker determines that there is an actual injuring process, then the Vice Chair stated that a substantial work-related stressor has been established. The decision-maker should not, at this point evaluate whether the worker’s stress reaction was excessive compared to the reaction expected from more typically similarly situated workers, who are not subject to a pre-existing condition. In this way, the “thin skill principle” is maintained. 

The Vice Chair’s application of the AWT test demonstrates how this framework is concerning. The Vice Chair held that the evidence before him satisfied the AWT because an average worker could “sustain a stress reaction involving some measure of impairment arising from the work-related stressors… [The stressors]…could, in my view, lead to a stress reaction in other similarly situated workers” (para 63). 

To find that a work-related stressor is substantial because an average worker would have a stress reaction and/or some measure of impairment and to not specify that the average person would experience a disabling mental reaction lowers the threshold of entitlement, suggesting the possibility of awarding widespread compensation for stress that is not predominantly work-related. 

2.     Were the Worker’s Work-Related Stressors the “Predominant Cause” Of the Worker’s Impairment? 

The Vice Chair further determined that the work-related stressors were the predominant cause of the worker’s impairment.  In conducting this analysis, the Vice Chair began by identifying that the predominant cause test is a noted departure from the “significant contribution” test that ordinarily applies in workers’ compensation law. 

Turning to the language set out in subsection 13 (4.1) of the WSIA which states that “the worker is entitled to benefits under the insurance plan as if the mental stress were a personal injury by accident”, the Vice Chair found support for the conclusion that workers who are claiming CMS entitlement shall be treated in the same manner as a worker who sustains any other personal injury. The Vice Chair held that subsection 13(4.1) should be considered an “interpretive lens” for the ‘predominant cause’ test. 

The Vice Chair’s application of subsection 13(4.1) as an interpretive lens to seems to disregard the WSIB’s intention to apply a different standard of causation for CMS entitlement. The Vice Chair held that because the worker was able to perform her job prior to the work-related stressor and was unable to perform her job after, that the stressor made a significant contribution to the worker’s impairment. Taking into consideration the substantial work-related stressor and the direction provided by subsection 13(4.1), the Vice Chair held that the “work-related stressors affecting the worker were the predominant or main cause of the worker’s impairment” (para 74). 

The Vice Chair provided no analysis regarding why the work-related stressor was the predominant or main stressor, which suggests that evidence that meets the ‘significant contribution’ test also meets the ‘predominant cause’ test. If this was their intention, the Vice Chair’s decision is inconsistent with the intent of the legislature and the WSIB’s intent as provided in OPM Document No. 15-03-14. 

i.     Intent of the legislature

Bill 127, Stronger Healthier Ontario Act (Budget Measures), 2017, repealed subsection 13(4) and extended entitlement to chronic mental stress. Bill 127 also added subsection 159(1.2), a section which explicitly allows the WSIB to create policies that provide for different evidentiary requirements when dealing with different types of entitlements. 

The addition of both of these provisions at the same time supports that the legislature did this purposely, intending to allow decision makers to adjudicate CMS claims using a different standard of cause than is traditionally used by the WSIB. Allowing the WSIB to utilize the ‘predominant cause’ test also mirrors the approaches taken by each of the other Canadian jurisdictions that currently allow for entitlement to benefits for CMS, such as British Columbia, Alberta, Saskatchewan and Quebec. [1] 

ii.     Intent of the WSIB 

The draft of Document 15-03-14 provided for consultation purposes included the significant contribution test. After consultation, the WSIB replaced the significant contribution test with the predominant clause test. In its WSIB Chronic Mental Stress Policy Consultation Summary, the WSIB stated that it reviewed, 

the use of these two causation tests and considered the feedback received from all stakeholders. The WSIB determined that the predominant cause test was more appropriate for dealing with the inherent complexity of chronic mental stress claims. Because of the pervasive nature of mental stress, both in and out of the workplace, it can be difficult to assess whether the workplace is a “significant” contributing factor to the injury. The use of the predominant cause test is also consistent with other workers’ compensation boards across Canada that also compensate for chronic mental stress. [2]

The WSIB clearly intended to depart from the significant contribution test. This departure is expressly noted in the policy, which states that the decision maker shall use the predominant cause test, rather than the significant contribution test. 

Where a Vice Chair is concerned that a WSIB policy is not consistent with the law or not applicable, the Vice Chair can refer the policy back to the WSIB for clarification before rendering a decision. The Vice Chair did not utilize this procedure before rendering their decision. 

The misapplication of the significant contribution test runs contrary to and directly opposes the intent of the legislation. It is clear that the intent of the legislation was to allow for decision makers to utilize a different test when determining entitlement to CMS. Foregoing the predominant cause test for the significant contribution test negates the intent of the policy drafters who and the 2017 amendments to the WSIA. 

Potential Consequences of Decision No. 693/20

Entitlement to CMS requires a different adjudication process than physical injuries because of the ubiquitous nature of stress. Utilizing the significant contribution test to allow for benefits related to CMS may lead to an overinclusion of entitlement, capturing individuals whose work-related stressors are not the main contributor to a worker’s impairment. Addressing entitlement issues related to CMS therefore requires a unique approach by the WSIB. An approach that takes into account the fact that while work related stressors may be a significant factor in someone’s life, they may not be the most significant factor leading to impairment. 

The potential implications of a high degree of workers obtaining compensation for non-compensable injuries is undesirable. This places a cost on employers that they cannot in good faith prevent, contradicting one of the principles of our workers’ compensation system, a principle which incentivises employers to create a healthy work environment. The workers’ compensation system is not intended to insure losses that are not attributable to the workplace. Additionally, allowing a system of adjudication for CMS entitlement that results in benefits coverage for stress that is not mainly a result of an injuring process raises equity issues with other classes of disabilities. [3]  

While an adjudicative framework for CMS is welcome, the framework provided needs to be more nuanced and tailored towards the unique nature of CMS than the significant contribution test allows. The significant contribution test is too vague and casts too wide of a net in order to effectively determine when an individual is properly in need of workers’ compensation coverage for CMS. It will be interesting to see whether the WSIAT follows the Vice Chair’s analysis in Decision No. 693/20 and/or whether the WSIB will intervene to provide further guidance to decision makers.


[1] see Liversidge, L.A LL.B. (June 26, 2017). Submission with respect to WSIB draft Operational Policy Paper: Document No. 15-03-14: Traumatic or Chronic Mental Stress (accidents on or After January 1, 2018) retrieved from < Microsoft Word - 20170626 LAL letter to WSIB consultation secretariat re stress FINAL.doc>

[2] see WSIB Chronic Mental Stress Policy Consultation Summary, October 2017, retrieved from <> at p. 4

[3] “Mental Disorders, Mental Disability at Work, and Workers’ Compensation,” William Gnam for the Institute for Work and Health to the Royal Commission on Workers’ Compensation in British Columbia, April 1998

About the authors

Julie Weller and Tristan Hunter are Associate Lawyers at Mathews Dinsdale, a leading workplace law firm which serves employers across Canada. Julie and Tristan advise both unionized and non-unionized employers on a variety of employment issues including workplace safety and insurance, discipline and discharge, and occupational health and safety.

Any article or other information or content expressed or made available in this Section is that of the respective author(s) and not of the OBA.