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Understanding Substance Use and Impairment in the Workplace

The Canadian Mental Health Association’s (CMHA) Impairment in the Workplace (2019) has been used as a guide in the following section.1

Individuals who use potentially intoxicating and addictive substances may progress along this spectrum. It’s critical to understand that substance use is not the same as having a substance use disorder (commonly known as addiction). Substance use, however, can be both beneficial and problematic.

Although many regularly used intoxicants should be considered (i.e., alcohol, stimulants, hallucinogens), the focus of this report will be on cannabis, and primarily medical cannabis.

What is impairment?

Impairment can arise from a variety of factors, including fatigue, traumatic shock, sleep deprivation, as well as from medical conditions or treatments, all of which have the potential to impair a person’s ability to perform their work.

Potential implications of Impairment

Impairment could potentially have the following implications:

–        Diminished judgement or decision-making|
–        Decreased motor coordination, reaction time or perception

The appearance of impairment (depending on the substance) may include the following observations:

–        Odour of alcohol or drugs
–        Glassy or red eyes
–        Unsteady gait
–        Slurring
–        Poor co-ordination

To ensure that medical cannabis is treated equally with other prescriptions, a clear definition of ‘impairment’ should be established, and all prescription medicine policies should be enforced equally.

Safety-sensitive positions

The Canadian Centre on Substance Use and Addiction defines safety-sensitive positions as:

“Organizations or positions where impaired employee performance could result in a significant incident affecting the health and safety of the individual, other employees, customers or the public, or could cause property damage”.2

A definition of a safety-sensitive position must be included in the organizational impairment policy.

Being ‘fit for duty’

‘Fit for duty’ is defined as an employee’s ability to be able to do their job safely and effectively without impairment. Organizations should define ‘fit for duty’ in their own terms within their policies, which will vary depending on the needs of the workplace, and the role of the employees.

Suspected problematic substance use in the workplace

Problematic substance use in the workplace can raise several concerns such as absenteeism, lower productivity, increased costs, and safety concerns.

The Canadian Centre on Substance Use and Addiction believes that addressing substance use in the workplace through comprehensive, well-developed policies sends the message that substance use and its possible implications are serious concerns. Strong policies also show that the company is committed to preventing impairment in the workplace, stigma, and discrimination, as well as assisting employees in their recovery.3

Accommodations in the workplace

Organizations may be required to prevent and move barriers and must provide accommodations for individuals that have a disability, short of undue hardship. According to the Ontario Human Rights Commission (OHRC), an employee has the right to be accommodated to the point of undue hardship if they are prescribed medication that may cause impairment because of a medical condition.4

The accommodation is made on an individual, case-by-case basis to fit the employee’s needs, with no preferences. If two accommodations that respond equally to the employee’s needs in a dignified manner are available, the employer has the right to choose the one that is less expensive or disruptive to the organization.5

With regards to accommodating medical cannabis, considerations may include:

1. Concerns related to cannabis scents
2. Permitted places of consumption
3. The impact of consumption on clients

[1] CMHA. (2019). Impairment in the workplace: what your organization needs to know. Toronto, ON: CMHA. Retrieved from
[2] Meister, S.R. (2018). A Review of Workplace Substance Use Policies in Canada: Strengths, Gaps and Key Considerations. Ottawa, ON: Canadian Centre on Substance Use and Addiction.
[3] Canadian Centre on Substance Use and Addiction. (2018). A Review of Workplace Substance Use Policies in Canada.
[4] Ontario Human Rights Commission. (2016) Policy on Drug and Alcohol Testing. Section 3: Code Protection.
[5] Ontario Human Rights Commission. (2016). Policy on ableism and discrimination based on disability.

Previous Article
An overview of Cannabis Use in Canada
Nearly 8% of Canadians aged 15 and up report using cannabis daily, and 15% have used cannabis in the previous 12 months.1 Canadians who reported using cannabis over the past 12 months were asked how frequently they used the substance. Over half (54%) reported using cannabis three days per month or less, and 18% reported daily cannabis use. According to a recent survey of Canadians aged 18 and above, most people, including those who are new to cannabis, as well as those who have been using it for a long time, report using it for medical purposes.2 Cannabis for Medical Purposes Of people who reported using cannabis for medical purposes in the past 12 months, the majority (76%) did not have a medical document from a healthcare professional. The most common frequency of use reported was daily (35%). The three main products used were dried flower (54%), cannabis oil for oral use (48%), and edibles (33%). Other products that weren’t used as often included vape pens, topical compounds, and beverages. For people using cannabis for medical purposes: 1.     26% reported consuming higher CBD and lower THC 2.     21% reported consuming higher THC and lower CBD 3.     12% reported consuming equal levels of THC and CBD 4.     15% reported consuming CBD only 5.     14% reported consuming mix of different products 6.     7% indicates they did not know the THC and CBD levels The top five sources to obtain cannabis for medical purposes were: 1.     Legal storefront (44%) 2.     Legal online source (23%) 3.     Health Canada Licensed producer (22%) 4.     A friend (17%) 5.     Growing their own (16%) Common clinical indications for medical cannabis 3 •       Pain and Inflammation -  Chronic musculoskeletal pain - Neuropathic pain - Arthritic inflammation - IBS / IBD •       Sleep, Anxiety, & Seizures - Certain anxiety, PTSD, and sleep disorders - Seizures (Dravet Syndrome) •       Nausea & Vomiting - N&V due to chemotherapy (CINV) - Anorexia due to HIV or other treatments - Appetite stimulant •       Movement & Spasticity - Motor disorders (PD, Huntington’s, Tourette’s) - Spasticity due to MS The above conditions broadly represent the areas where cannabinoids have demonstrated the most efficacy in symptom management. As you can see, many of these conditions come under the 'Pain Triad' arms. See Canada’s opioid overdose crisis and living with chronic pain blog posts for more information. 4 References: [1] Government of Canada. (2021). Canadian Cannabis Survey 2020: Summary. Retrieved from: [2] Deloitte. (2021). Seeding new opportunities: Listening to Canada’s cannabis consumer. 2021 Cannabis Consumer Report. Retrieved from [3] National Academies of Sciences, Engineering, and Medicine, Health and Medicine Division, Board on Population Health and Public Health Practice & Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. (National Academies Press (US), 2017). [4] CMHA. (2019). Impairment in the workplace: what your organization needs to know. Toronto, ON: CMHA. Retrieved from
Next Article
Developing a Workplace Impairment Policy
The Canadian Mental Health Association’s (CMHA) Impairment in the Workplace (2019) has been used as a guide in the following section.1 Include clear definitions for key terms: 1.     Impairment 2.     Safety-sensitive positions 3.     Expectations for being ‘fit for duty’ Develop a clear protocol in the event of impairment in the workplace ·       Ensure that managers and supervisors will address any concerns about an individual's capacity to execute their work safely in a discreet and timely way. ·       Make it clear that employees who are intoxicated at work will be sent home as soon as possible, with transportation arranged. ·       Determine who will oversee documenting any events and who will be contacted. ·       Outline how to deal with the situation when it happens so that you can grasp the facts and analyze any accommodations or other results. ·       Make sure that everyone on staff is aware of the protocol. ·       Think about if the policy applies to all employees or whether there are different protocols for different staff or volunteer positions. Identify duties of employers Duty to inquire When an employer observes changes in an employee's performance, attendance, or behaviour that could suggest problematic substance use or impairment, the employer should first offer help and accommodation before imposing discipline or other consequences. Employers should routinely advise employees who work in safety-sensitive positions about the requirement to disclose whether they are using a substance that could cause on-the-job impairment, according to the Ontario Human Rights Commission.2 Duty to accommodate People who take medications (including cannabis) for a disability or health condition as well as people with substance use disorder have the right to seek accommodation to the point of undue hardship. However, accommodation does not mean permitting cannabis impairment on the job. Identify duties of employees To the best of their abilities, the employee with the disability or health condition must communicate their accommodation needs. Some employees may be hesitant to share personal health information for fear of being stigmatized or discriminated against. Employees should be informed that it is their responsibility to disclose, but that they will not suffer punishment if they do so, and that their employer will cooperate with them to build a plan and keep information confidential. The policy should outline expectations of employees, which may include: 1.     Arrive fit for duty and remain as such for the duration of their shift 2.     When off duty, refuse a request to come into work if unfit for duty 3.     Come forward to management if a colleague is impaired by substances. Drug Testing Drug testing in the workplace in Canada can be controversial, as there are two competing factors to consider: maintaining individuals' human and private rights, while ensuring employee and public safety. Furthermore, because cannabis is lipophilic (fat soluble) and can remain in the body for a long time. Current drug testing methods are insufficient for accurately assessing the degree of cannabis impairment. Employers will have to evaluate their drug testing policies on a regular basis until a reliable method of impairment testing becomes available. 1 Testing situations The different types of testing situations include: (1) pre-employment; (2) reasonable grounds and post-incident testing; (3) random testing; and (4) testing as part of a rehabilitation plan.3 There is some controversy over drug and alcohol testing in the workplace, and discrimination and infringement of rights should be considered. In certain situations, an employer testing for drug and/or alcohol usage in a "safety-sensitive" employment is permissible. How to test for presence of cannabis in the body Point-of-care testing (POCT) of oral fluids and urine are possible, but they do not always correlate with impairment. Furthermore, THC is the cannabinoid tested for, and all cannabis products, including those with a high CBD content, include some THC. Oral fluid POCTs are the most advanced type of tests currently available, and they can indicate recent use. Urine POCTs are considered an inaccurate way of testing, because some people can test positive for THC in their urine for up to two months after their last use. 5 Although oral fluid testing is the most advanced assay available, it is still considered a qualitative test, meaning that even a trace amount of THC (such as that present in non-sedating CBD oil) might cause a 'positive' result. Therefore, the future of drug testing should be quantitative, with a specified threshold that allows an employer to know that if an employee tests positive, then they are truly impaired. Impaired driving Drug-impaired driving has been a criminal offence since 1925. Cannabis-impaired driving can result in injury or death. There is no set amount of time to wait before driving after using cannabis, therefore never drive when impaired, and never get into a car with an impaired driver. Law enforcements are trained to detect drug-impaired driving using:4 ·       Standard Field Sobriety Test (SFST), which is typically administered at the roadside ·       Drug Recognition Expert (DRE) evaluation, which includes a series of tests and a toxicological sample (urine and blood) ·       Oral fluid drug screening equipment ·       Blood samples Currently in force in Canada, the impaired driving laws (Bill C-46) include limits for THC. These limits are as follows:5 ·       2 nanograms (ng) but less than 5 ng of THC: Having at least 2 ng but less than 5 ng of THC per millilitre (ml) of blood within two hours of driving would be a summary conviction criminal offence. ·       5 ng of more of THC: Having 5 ng or more of THC per ml of blood within two hours of driving would be a hybrid offence. Hybrid offences are offences that can be prosecuted either by indictment, in more serious cases, or by summary conviction, in less serious cases. ·       Combined THC and alcohol: Having a blood alcohol concentration (BAC) of 50 milligrams (mg) of alcohol per 100 ml of blood, combined with a THC level greater than 2.5 ng per ml of blood within two hours of driving would also be a hybrid offence. Department of Justice Canada (2018) also notes that: ·       Oral fluid drug screeners can detect some or all of THC, cocaine, and methamphetamine, the three most common impairing drugs found in Canadian drivers. Police can demand an oral fluid sample if the officer has a reasonable suspicion that the driver has drugs in their body based on objectively visible facts, such as: •   red eyes •   muscle tremors •   agitation •   speech patterns If a driver tests positive on an oral fluid screening test, the positive result would confirm the presence of the drug, and combined with other signs of impairment observed by the police at the roadside, would provide grounds for the investigation to proceed further either by making a demand for drug recognition and evaluation (DRE) or a blood sample. Employee Education and Prevention Educational material can provide information on: 1.     All factors to consider with medical cannabis including types of cannabis products, product labelling, listed cannabinoid content, administration factors in cannabis delivery methods, impairment, and effects of cannabis on youth.6 2.     Knowledge of the role and responsibilities, as well as how impairment will be assessed (e.g., fit to work).7 3.     Substance use education and training, including cannabis, prescription drugs, alcohol, and illicit drugs. 7 4.     Availability of current resources and services for an individual and their family. 7 5.     Consequences of disciplinary action if the organization's policy is broken.7 6.     The employer's policy and procedure for accommodating employees.7 7.     How to recognize and report signs and symptoms of impairment in others to their supervisor or employer. 7 Download the sample checklist for developing a workplace impairment policy here. References: [1] CMHA. (2019). Impairment in the workplace: what your organization needs to know. Toronto, ON: CMHA. Retrieved from [2] Ontario Human Rights Commission. (2018). Policy Statement – Cannabis and the Human Rights Code. [3] Ontario Human Right Commission. (2016). Policy on drug and alcohol testing 2016. Toronto: OHRC. Retrieved from [4] Beirness, D.J., & Porath, A.J. (2019). Clearing the smoke on cannabis: Cannabis use and driving. Ottawa: Canadian Center on Substance Use and Addiction. Retrieved from [5] Government of Canada. (2021). Legislative Background: reforms to the Transportation Provisions of the Criminal Code (Bill C-46). Retrieved from [6] Habrel, M. (2018). Blazing the Trail: What the Legalization of Cannabis Means for Canadian Employers. Ottawa: The Conference Board of Canada. [7] Canadian Centre for Occupational Health and Safety. (2018). Workplace strategies: risk of impairment from cannabis, 3rd edition. Retrieved from