Why was this study done?
While cannabis is often used recreationally, there is growing interest in its use for therapeutic purposes, such as for pain, anxiety, depression and sleep problems. Among working adults who have experienced work-related injuries or illnesses, some may turn to cannabis to ease these types of symptoms arising from their conditions. However, little is known about patterns of cannabis use among this group. Little information also exists on how much guidance health-care providers may give to workers on using cannabis for a work-related condition.
How was the study done?
This study set out to examine the characteristics of injured/ill workers who used cannabis—either because of their work-related conditions or for other reasons—in comparison with injured/ill workers who did not use cannabis, in the months following a work-related injury or illness. The study also compared patterns of use between the workers who used cannabis to treat their work-related condition and those who used for other reasons.
To conduct this study, the research team drew on data from two rounds of the Ontario Life After Work Injury Study (OLAWIS), an IWH-led research project examining the health and labour market outcomes of Ontario workers after they’ve experienced a work-related injury or illness. The sample of 1,196 participants in this study were at least 18 years old and had an accepted lost-time compensation claim with the provincial workers’ compensation system—i.e., the Workplace Safety & Insurance Board (WSIB). Participants were interviewed 18 to 36 months after experiencing a physical injury or illness and were asked about their cannabis use, including whether they had used cannabis in the previous year, and whether it was used to treat their work-related condition. They were also asked about their work status and their health.
What did the researchers find?
The vast majority of workers in the study (72.6 per cent) reported that they hadn’t used cannabis at all in the last year. Over that same time frame, 13.3 per cent said they used cannabis for reasons unrelated to their work-related condition, and 14.1 per cent said they used cannabis to treat their work-related condition.
Compared to other injured/ill workers who used cannabis, the injured/ill workers who used cannabis to treat their work-related conditions were more likely to report:
- using cannabis daily;
- using cannabis that does not make them high;
- having started using cannabis because of their condition;
- using cannabis for a mix of medical or and non-medical purposes, with pain, sleep, and mental health most frequently cited as medical reasons;
- being able to decrease their use of prescription medications and alcohol in the past year as a result of their cannabis use; and
- experiencing beneficial impact of cannabis use on their physical and mental health.
Compared to all other workers in the study, injured/ill workers who used cannabis to treat their work-related condition were more likely to report:
- experiencing financial difficulties and longer WSIB claim durations;
- not working, or not working with the employer where they experienced their injury/illness;
- currently receiving health-care for their condition;
- experiencing quite a bit or extreme pain interference with their work, and greater pain intensity due to their work-related condition; and
- experiencing poor general health, greater psychological distress, and sleep difficulties.
Among those using cannabis for their work-related condition, two-thirds (67.3 per cent) did so without receiving guidance on therapeutic cannabis use from a health-care provider. The one-third who did seek out medical guidance did so from a general practitioner, family physician or specialist. The guidance mostly related to what the benefits, risks and side effects are, and to how often and how much to take.
What are the implications of the study?
Findings from this study demonstrate that workers are turning to cannabis many months following the onset of their original work-related condition, mostly without medical guidance. Workers using cannabis to treat their work-related condition also appear to be struggling the most with recovery, reporting more pain along with greater sleep and mental health difficulties than the other groups. With growing public interest in the use of cannabis for medical purposes, greater access to legal sources of cannabis, and an increasing number of workers’ compensation organizations developing formal policies on medical cannabis, health-care providers will likely continue to encounter workers using cannabis for their work-related conditions. Health-care providers should be aware that their patients may be using cannabis to manage physical and mental symptoms arising from a work-related condition and be prepared to speak candidly with workers about their cannabis use, including potential harms and benefits, as well as issues of workplace impairment.
What are some strengths and weaknesses of the study?
A strength of this study is its novel finding about workers’ use of cannabis for their work-related conditions, a population for which little data exist. Another strength is the large sample of workers included in the study, which was drawn from the entire population of interest (i.e., adult workers who had experienced a work-related injury or illness resulting in lost-time claims to the WSIB).
A weakness of this study is the cross-sectional study design. Because the data were collected at one time point (18 to 36 months post-injury or illness onset), the study cannot shed light on whether problems with recovery led workers to seek cannabis use or whether cannabis use worsened recovery. There is also no data available on cannabis use patterns in the early period after a workers’ injury or illness onset, as this study only had data on cannabis use 18 or 36 months after.