Mental Health and Workplace Investigations

If you work in an office with ten or more people, it would not be unusual if someone you work with has recently had some kind of a mental health challenge.

The Canadian Association of Mental Health says, in any given year, twenty percent of people in Canada will personally experience a mental health problem or illness. They also note that, by age 40, about 50 percent of the population will have or have had a mental illness. As you might imagine, COVID has not helped these statistics.

Lost in the numbers is the fact that there is a wide range of mental health challenges, and not every mental health issue is equal: some people manage their condition without any noticeable impact at work, and others may experience a more disruptive impact on their work and personal lives.

Sometimes, mental health issues create or contribute to conflict in the workplace. So, you might be wondering how we, as lawyers and investigators, handle investigations where mental health challenges are present.

Credibility and Mental Health Stigma

It’s important to state we are lawyers, not doctors. We cannot diagnose a mental illness, and it would not be appropriate for us to do so.

We always start from the point of assuming all parties are able to reason clearly and conduct themselves appropriately in a given work setting, while accounting for the stress of taking part in an investigation which can range from mild to acute. Oftentimes, in the course of an investigation, a party may disclose a mental health condition or mental illness, or may appear to have unusual behaviours and/or perceptions. It is important to remember that a mental illness may be a protected ground under the Ontario Human Rights Code as a kind of disability. Individuals with disabilities cannot be discriminated against due to their disability. One way discrimination or prejudice against individuals with mental illness can show up in a workplace investigation is if an investigator too quickly dismisses or disbelieves a person’s evidence based on common assumptions associated with mental illness. It is important for investigators and employers to ensure they are not basing their conclusions about an employee on stereotypes regarding people with mental illness.

Knowledge that a party has a mental illness does not mean that their conduct or their allegations are a result of mental illness. Mental illness may be a factor to be considered but our fact-finding process is still led by basic principles. Ultimately, we assess if their claims are reasonably supported by the evidence provided, their testimony, the testimony of other witnesses and especially more objective evidence like texts, emails, other business records like invoices, photos, video, etc.

To determine the facts, we ask ourselves questions like: “Do the interviewee’s perceptions match up to reality?”. This is primarily based on what their co-workers are saying and on the objective evidence (texts, emails, etc.). We also ask ourselves: “Is a person’s interpretation of events reasonable in a broader sense?” This could be about the likelihood of certain events taking place, the ordering of events, the likelihood of coincidence, societal norms related to context, internal inconsistencies in a person’s narrative, and a host of other big-picture considerations.

A recent arbitration case reaffirmed these fundamental principles for assessing credibility when one party seems to have a distorted narrative of events or a narrative that doesn’t align with reality. In Gate Gourmet Canada Inc. v Teamsters Local Union No. 647, 2023, the arbitrator reviewed a workplace harassment investigation which found that the respondent harassed several female colleagues and was subsequently terminated. He grieved the termination. The arbitrator did not explicitly deal with mental health issues but noted that “the grievor tends to make pronouncements, perhaps seeing things as he wished them to be, but is often proved to be wrong.” The arbitrator also noted that there was concern about the grievor’s “ability to appreciate the impact of his aggressive behaviour on others.” For several reasons, the arbitrator found “the grievor does not emerge from the process as a reliable narrator.”

The arbitrator in this case reiterated that credibility assessments are informed by several factors including the reasonable probability of the incident, clear and straightforward delivery of evidence, and consistency with other witnesses. This arbitration decision also relied upon the seminal case for the test of witness credibility, Faryna v. Chorny, 1951:

“In short, the real test of the truth of the story of the witness in such a case must be its harmony with the preponderance of the probabilities which a practical and informed person would readily recognize as reasonable in that place and in those conditions…Again, a witness may testify to what he sincerely believes to be true, but he may be quite honestly mistaken.”

Disclosure of Mental Illness and Workplace Harassment

Mental illness and particularly someone’s specific knowledge of another coworker’s mental illness is also an important factor to consider when assessing harassment because the definition of workplace harassment considers the standard of a “reasonable person” in the positions of the parties. This means we must assess whether a reasonable person in the position of the complainant would find such conduct to be unwelcome and, if so, whether a reasonable person in the respondent’s position ought to know that to be the case. This can make for an interesting analysis when an employer behaves in a way that may be welcome to most employees but is known to be unwelcome to a worker with a disclosed mental illness. Just as you wouldn’t ask an employee with a broken leg to run up ten flights of stairs, you shouldn’t ask someone who has disclosed their claustrophobia (an anxiety disorder) to work in a tight space.

Another challenging example for employers may be employees with anxiety disorders or post-traumatic stress disorder (PTSD) that could manifest as anxiety around authority figures. This is something commonly reported by some residential school survivors and can make behaviours that appear innocuous from the outside, experienced as deeply hurtful by those with the condition. Knowledge of complex mental health issues can help employers and other employees understand that what may on the surface appear as unreasonable conflict or push-back from an employee may in fact be reasonable and possibly an issue deserving of accommodation.

We recognize that there is significant stigma attached to mental illness and that employees may not wish to disclose their challenges due to shame, fear of job loss, or feelings of inadequacy. If a diagnosis of a mental health issue is shared with us during an investigation, it can sometimes help us understand the problem. For instance, if an employee has a specific trauma or condition that makes a particular type of work or aspect of their job difficult for them, that helps us get to the root of a particular conflict. This is especially important when their employer is already aware of the mental health concern and is not accommodating an employee – which may be a form of workplace harassment or discrimination. If it is not disclosed to the employer, it may not meet the definition of workplace harassment. When mental health issues are disclosed to investigators, this can also help us make helpful recommendations to make the workplace safer and improve relationships.

An employee could also be facing a brand new challenge with mental health brought on by personal life circumstances, such as a divorce, death in the family or other trauma. One day the employee is fine, and the next day there is a noticeable shift in effectiveness at work, attitude, or other problem behaviours. In short, understanding context is always critically important.


The role of mental health in workplace conflict is a difficult issue to address, yet it is often central to our work. We will not offer a diagnosis – our job is to determine whether something alleged to have happened did or did not happen, and if it did, whether or not it constituted a form of harassment. Often, when presenting reports for which recommendations were part of our mandate, we will encourage employers to offer counselling to the employees who are a part of our investigative work to ensure they can talk and work through whatever challenges they may be facing. Employers with Employee Assistance Programs ought to direct employees to these programs whether they are the respondent or the complainant in an investigation.

We would never allow someone’s mental illness or disorder to diminish their ability to defend themselves or tell their story. This is why we give plenty of notice and flexibility when scheduling first interviews with the parties, we let them know in advance that they may have a support person present, and we even offer them the opportunity to put their thoughts in writing instead, or both.

Occasionally we break the interviews up into multiple days and use techniques and strategies to help diminish the effect this difficult experience might have on the person and ensure the feeling of safety in the process. We strive to make our interviewing process trauma-informed and uphold the highest levels of procedural fairness, regardless of who we are interviewing. The respondent always gets a written summary of the allegations against them and any supporting documents we have been provided. The aim is to provide enough detail in a summary that the respondent has a meaningful opportunity to defend themselves and present their side of the story. We are also always careful to explain to respondents that we will not make any conclusions until we have heard all the evidence. Whether a party has a mental illness or not, drawing attention to this basic and essential approach to our work goes a long way to set people at ease.

The most important thing is to listen well, and that involves not just listening but demonstrating that one is absorbing what is being said. We know that how we, as investigators, conduct ourselves in interactions with the parties directly impacts not only their experience and confidence in the investigation, but it also directly impacts the quality of the information we receive and thus the accuracy of our conclusions and ultimately the value of the investigation report. Investigation reports are used by employers to make important workplace and business decisions. Investigators need to get it right for all concerned.

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