Workers’ Compensation Update: Work-Related Chronic and Traumatic Mental Stress

Workers’ Compensation Update: Work-Related Chronic and Traumatic Mental Stress

On January 1, 2018, very significant legal changes were made to Ontario’s workers’ compensation system. Adapting to these changes will require amendments to employment policies, workers’ compensation / occupational health and safety training programs, and return to work accommodations. In our view, these changes will also result in an overall increase in WSIB claims and premiums.


On May 17, 2017, the Ontario legislature enacted Bill 127 – Stronger, Healthier Ontario Act (Budget Measures), 2017 (“Bill 127”). While Bill 127 was primarily focused on financial policy, Schedule 33 of the legislation quietly introduced certain fundamental amendments to the Workplace Safety and Insurance Act (the “WSIA”).

Pursuant to Bill 127, the WSIA would, for the first time, extend workers’ compensation coverage to injuries arising as a result of work-related “mental stress”. Section 13 of the WSIA now states:

Mental Stress

13(4) Subject to subsection (5), a worker is entitled to benefits under the insurance plan for chronic or traumatic mental stress arising out of and in the course of the worker’s employment.

Same, exception

13(5) A worker is not entitled to benefits for mental stress caused by decisions or actions of the worker’s employer relating to the worker’s employment, including a decision to change the work to be performed or the working conditions, to discipline the worker or to terminate the employment.

Following the enactment of Bill 127, the WSIB conducted a series of public consultations, beginning in May and ending in July of 2017. Shortly thereafter, the WSIB Board of Directors indicated to industry stakeholders that it would publish two (2) standalone policies pertaining to entitlement for Traumatic Mental Stress (“TMS”) and Chronic Mental Stress (“CMS”) claims under the WSIA.

On January 2, 2018, the WSIB published the following policies:

  1. WSIB Operational Policy Manual 15-03-14Chronic Mental Stress (Accidents on or After January 1, 2018) (“OPM 15-03-14”)
  2. WSIB Operational Policy Manual 15-03-02Traumatic Mental Stress (“OPM 15-03-02)

The details of the foregoing legal changes, and the potential implications for employers of said changes, are discussed in detail below.


On January 2, 2018, the WSIB published its standalone policy on CMS related workplace injuries. For a worker to prove entitlement to WSIB benefits for CMS related injuries under this policy, the following four (4) conditions must be met:

a) The worker must have experienced a “substantial work-related stressor”;

b) The “work-related stressor” must have been the “predominant cause” of an injury to the worker;

c) The injury must have been “appropriately diagnosed”.

a) Substantial Work-Related Stressor (e. “arising out of and in the course of the worker’s employment)

While not strictly defined, OPM 15-03-14 contemplates that a “substantial work-related stressor” must be “excessive in intensity and/or duration in comparison to the normal pressures and tensions experienced by workers in similar circumstances”.

By way of example, OPM 15-03-14 states that workplace harassment is an example of a “substantial work-related stressor” that may entitle an individual to WSIB benefits for CMS related workplace injuries. By contrast, OPM 15-03-14 indicates that an “interpersonal conflict” between a worker, their supervisor(s), co-worker(s), and/or customer(s), will not generally be considered a “substantial work-related stressor”, unless such conflict amounts to workplace harassment (which is defined to include workplace bullying).

OPM 15-03-14 also indicates that entitlement to benefits for CMS related workplace injuries will not be available when CMS is caused by “decisions or actions of the worker’s employer relating to the employment”, when those actions are properly “part of the employment function”. The policy lists the following examples of actions that are typically “part of the employment function”:

  • Termination;
  • Demotion;
  • Transfer;
  • Discipline;
  • Changes in working hours; or
  • Changes in productivity expectations.

Conversely, if the CMS suffered by the employee is the result of employer actions which are not related to the “employment function”, workers may be entitled to claim WSIB benefits.

The policy goes on to clarify that employees in jobs with a high degree of “routine stress” should not be denied benefits simply because all workers in their specific job category or job classification experience a high degree of “routine stress”. According to the policy, jobs with a high degree of routine stress will typically have “one or both of the following characteristics”:

  • responsibility over matters involving life and death, or
  • routine work in extremely dangerous circumstances.

b) The Work-related Stressor must be the Predominant Cause of Injury

According to OPM 15-03-14, this does not mean that the work-related stressor must be the “sole” or “exclusive” cause of the worker’s mental stress injury, but rather that the work-related stressor must be the “primary or main cause” of the mental stress injury “as compared to all of the other individual stressors”. Critically, the “substantial work-related stressor” can still be considered the predominant cause of a work-related mental stress injury, even though it may be cumulatively outweighed by the worker’s other stressors, when combined.

c) “Appropriately Diagnosed”

According to OPM 15-03-14, in order to be “appropriately diagnosed” a worker’s alleged work-related mental stress injury must be:

i. Diagnosed in accordance with the Diagnostic and Statistic Manual of Mental Disorders (“DSM”); and

ii. Diagnosed by a “qualified regulated health care professional”.

OPM 15-03-14 clarifies that the term “qualified regulated health care professional” will include medical professionals who are qualified to provide a DSM diagnosis. Pursuant to the Regulated Health Professionals Act, 1991, the list of health professionals authorized to provide a DSM diagnosis is limited to:

  • Physicians;
  • Nurse Practitioners;
  • Psychologists; and
  • Psychiatrists.

To substantiate entitlement to WSIB benefits under the policy, the worker’s CMS injury diagnosis must be made according to the DSM, and may include conditions such as:

  • An anxiety disorder;
  • A depressive disorder;
  • Acute stress disorder;
  • Posttraumatic stress disorder; or
  • Adjustment disorder.


The WSIB regards a claim for TMS related workplace injury as separate and distinct from a claim for CMS related workplace injury. For a worker to prove entitlement WSIB benefits under this policy, the following four (4) conditions must be met:

a) The worker must have experienced one or more “traumatic events” (multiple events are referred to as “cumulatively traumatic events”);

b) The “traumatic event(s)” must have “arisen out of and in the course of the worker’s employment”;

c) The “traumatic event(s)” must have “caused” the worker to suffer a “mental stress injury”;

d) The “mental stress injury” must have been “appropriately diagnosed”.

a) Traumatic Event

OPM 15-03-02 identifies that a traumatic event may be a result of a criminal act, or a “horrific accident”. Alternatively, a traumatic event may involve “threatened death or serious harm against the worker, a co-worker, a worker’s family member, or others”. The policy identifies that, in most cases, a traumatic event will be “sudden and unexpected”.

b) “Arising out of and in the course of employment”

In all cases, the “traumatic event(s)” must arise out of and occur in the course of a worker’s employment. As per OPM 15-03-02, in order to prove entitlement to benefits, the “traumatic event(s)” must be:

  • Clearly and precisely identifiable; and
  • “objectively traumatic”.

According to the policy, this means that the event(s) can:

  • Be established by the WSIB through information or knowledge of event(s) provided by co-workers, supervisory staff, or others (e. via witness statements or direct testimony); and
  • The event(s) is (are) “generally accepted as being traumatic”.

OPM 15-03-02 goes on to list the following non-exhaustive list of potential work-related “traumatic events”:

  • witnessing a fatality or a horrific accident
  • witnessing or being the object of an armed robbery
  • witnessing or being the object of a hostage-taking
  • being the object of physical violence
  • being the object of death threats
  • being the object of threats of physical violence where the worker believes the threats are serious and harmful to self or others (e.g., bomb threats or confronted with a weapon)
  • being the object of workplace harassment that includes physical violence or threats of physical violence (e.g., the escalation of verbal abuse into traumatic physical abuse), and
  • being the object of workplace harassment that includes being placed in a life-threatening or potentially life-threatening situation (e.g., tampering with safety equipment; causing the worker to do something dangerous).

The policy also clarifies that the worker must have:

  • “suffered or witnessed the work-related traumatic event(s) first hand, or
  • heard the work-related traumatic event(s) first-hand through direct contact with another traumatized individual (g. speaking with victims over the radio, or on the telephone while a traumatic event is occurring.

OPM 15-03-02 notes that, due to the nature of certain occupations, some workers may, over time, be exposed to “multiple traumatic events” which have a “cumulative effect” on the worker. The policy also recognizes that a worker may not “show the effects” of exposure to a traumatic event, or a series of traumatic events immediately.

In this regard, the policy states that the WSIB’s adjudicators will primarily rely upon clinical and other information supporting a worker’s claim that multiple traumatic events led to a work-related traumatic mental stress injury. The WSIB can consider multiple sources of evidence, including evidence of any alleged disruption to the worker’s life.

c) “Caused an injury to the worker”

OPM 15-03-02 identifies that entitlement to benefits for traumatic mental stress requires proof, on a balance of probabilities (i.e. “it is more likely than not”) that the traumatic event(s), or the cumulative effect of a series of traumatic events:

  • Arose out of and in the course of a worker’s employment; and
  • Caused or significantly contributed to, an “appropriately diagnosed” mental stress injury.

d) “Appropriately Diagnosed”

According to the policy, the WSIB will have reference to the DSM, and require an “appropriate diagnosis” to be made by a “qualified regulated health care professional”. The related diagnostic requirements and the list of qualified health care professionals sanctioned to provide diagnoses for the purposes of this policy are identical to those cited in the WSIB’s policy on CMS (above).


On December 14, 2017, the Ontario legislature passed Bill 177, entitled the “Stronger, Fairer Ontario Act (Budget Measures), 2017. Bill 177 is omnibus legislation which, among other things, introduced into law significant transitional rules which govern the application of the new TMS and CMS provisions under the WSIA.

Pursuant to Bill 177, claimants who have not yet filed a mental stress injury claim for an injury that occurred between April 29, 2014 and January 1, 2018 will have until July 1, 2018 to file a claim related to that injury.

Additionally, mental stress claims that were already filed and are pending before the WSIB on January 1, 2018 will be adjudicated pursuant to the new policies, regardless of the date on which the worker’s alleged mental stress occurred.

Bill 177 also states that if a CMS- or TMS-related claim is pending appeal to the Workplace Safety Insurance Appeals Tribunal (“WSIAT”) as of January 1, 2018, it will be referred back to the WSIB where it will be adjudicated pursuant to the new provisions, regardless of the date on which the worker’s mental stress occurred.

Bill 177 goes on to clarify that mental stress claims that have already been denied by the WSIB or the WSIAT cannot be refiled or reconsidered by workers.


As of January 1, 2018, employers will be obligated to report compensable CMS- and TMS-related workplace injuries to the WSIB as and when they occur. We anticipate that employers are likely to face significant new challenges with respect to returning injured workers to work, where possible, after a compensable work-related mental stress injury has occurred.

Furthermore, the WSIB claims adjudication system, which is already significantly backlogged, will likely have to expand to address a potentially substantial increase in the number of CMS- and TMS-related claims. In our view, the recent enactment of the transitional rules under Bill 177 (particularly the fresh six [6] month period within which to file a mental stress claim) will lead to increased WSIB claims, increased employer premiums, and further claims adjudication delays.

On the other hand, because the WSIA limits an employee’s right to sue their employer for compensable injuries that are covered under the WSIA, employers may be able to more easily defend civil actions initiated by employees who seek damages for tortious harassment and intentional infliction of mental stress in the workplace. In that regard, employers may be able to argue that the proper venue for seeking compensation related to those claims is the WSIB, as opposed to the civil tort system.

Going forward, employers are best advised to review their workplace practices and policies, in an effort to eliminate potential causes of work-related mental stress. Employers may have conducted similar reviews following the Bill 168 and Bill 132 amendments to the Occupational Health and Safety Act. Employers will also benefit from proactively training their supervisory and managerial staff regarding these significant changes to the WSIA, including the WSIB’s new policies, as soon as possible.

Co-authored by Tushar Anandasagar and Lucas Hendsbee.

Tushar Anandasagar is an Associate Lawyer at LeClair and Associates P.C. He works in all areas of Labour and Employment law, with a particular focus on Workplace Health and Safety compliance and related issues. For further information or discussion, please contact Tushar by email at

Lucas Hendsbee is a Research Assistant at LeClair and Associates P.C. He provides research and analysis regarding all areas of the law, with a focus on regulatory compliance, policy analysis and emerging legal issues. For further information or discussion, please contact Lucas by email at

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