- Second Injury and Enhancement Fund {SIEF} (severity of preexisting condition)
- Preexisting condition (cannabis use disorder)
The worker suffered an electric shock injury on August 24, 2022, while working as a shift supervisor. The WSIB recognized entitlement for injury to the left upper extremity with sensory deficits and muscle weakness, later expanded to include post-traumatic stress disorder (PTSD) and major depressive disorder (MDD). The employer sought SIEF cost relief, claiming the worker's pre-existing Cannabis Use Disorder impacted and prolonged recovery.
The Vice-Chair allowed the appeal.The worker had a longstanding 10-year history of daily cannabis use prior to the accident. A psychiatric assessment at the Burn Specialty Clinic diagnosed Cannabis Use Disorder post-accident, based on this history. There was no evidence of prior depression, PTSD, or psychological treatment, indicating no pre-accident disability related to the disorder.The SIEF policy allows consideration of prior life experiences or behavioral disorders that predispose a worker to psychological conditions, even if no prior disability existed. The key question was whether the Cannabis Use Disorder made the worker more vulnerable to developing PTSD and MDD or prolonged recovery.The employer submitted medical literature on Cannabis Use Disorder and its association with depression and PTSD. These articles were general and not specific to the worker, limiting their persuasive value. The WSIAT Medical Discussion Papers on PTSD and Depression noted inconclusive evidence on the effects of cannabis, emphasizing the need for more research.The employer obtained a Medical Consultant Review from a psychiatrist who reviewed all case materials and concluded that the workplace accident was the primary cause of the PTSD and MDD, but that Cannabis Use Disorder was a predisposing factor. He opined cannabis use likely played no more than a minor role in the development and severity of the psychological conditions and had a minor impact on prognosis. This aligned with the WSIAT's Medical Discussion Paper on Depression which notes that the causes of depressive disorders are multi-factorial.The Vice-Chair found that the Cannabis Use Disorder was a pre-existing condition that predisposed the worker to developing PTSD and MDD and likely enhanced or prolonged recovery. Applying the SIEF matrix, a minor pre-existing condition combined with a moderate accident severity resulted in 25% cost relief to the employer.