Ninety workers in a Fort McMurray health study evacuated during the 2016 wildfire. About 102 days later, 15 of them had scores indicating moderate or severe anxiety or depression.
The evacuation did not end when people returned home.
One year after the wildfire, insomnia was the most common probable diagnosis in another survey of current and former residents who had been evacuated. It affected 28.5% of respondents. Probable post-traumatic stress disorder affected 15.4%. Major depressive disorder affected 15%. Generalized anxiety disorder affected 14.2%. More than one in three had at least one probable diagnosis.
Then came the children.
A study of 3,070 students in grades 7 through 12 found rates of probable PTSD at 37%, probable depression at 31% and probable anxiety at 27%. Students directly affected by the fire had more severe symptoms and lower scores for self-esteem, quality of life and resilience. A later study followed survey results from 9,376 Fort McMurray students between 2017 and 2019. Their mental health did not steadily recover. Symptoms and rates of probable PTSD, depression, anxiety, drug use and alcohol use worsened over those three years.
These findings sit inside a new Public Health Agency of Canada review of climate change and mental health research. Its authors examined 72 Canadian studies published between 1990 and 2024. The record they assembled shows that the psychological effects of wildfire, flood, extreme heat and gradual environmental change can persist long after the immediate danger has passed.
It also shows how little of Canada has been studied.
Five Years After Fort McMurray
The review divides mental-health effects into three periods: short term, up to two months; intermediate, more than two months but less than a year; and long term, one year or more.
Long-term effects appeared in 46 studies. Anxiety was the most frequently reported long-term outcome, appearing in 25. Adverse mental-health effects appeared in 22, depression in 19 and PTSD in 13.
Fort McMurray supplied the clearest chronology.
Six months after the wildfire, a survey of 486 residents found a 12.8% one-month prevalence of likely PTSD. Respondents with likely PTSD were more likely to be living in a different home, to have a history of anxiety, to report inadequate support and to have received counselling. Complete home loss and property loss in general were not significant predictors in that study.
At 18 months, researchers surveyed 197 employees from two Fort McMurray school districts. Likely major depressive disorder affected 18%, likely generalized anxiety disorder affected 16% and PTSD affected 10%. Nineteen per cent of the staff members had lost their homes.
Five years after the fire, 186 residents answered another survey. Among that group, 46% had depression, 44% had anxiety, 41% had likely PTSD and 40% had low resilience. One-third used antidepressants. Forty per cent had received mental-health counselling in the previous year. The survey sample was not a cross-section of the city: 86% of respondents were women, 95% were employed and 72% were in a relationship.
That distinction matters. The numbers describe the people surveyed. They do not establish the prevalence of those conditions across Fort McMurray.
The review’s authors make the same point on a national scale.
The Climate Change Mental Health Evidence Narrows
Of the 72 studies in the review, 30 were conducted in Alberta. That is 42% of the studies the authors included. Many centred on the Fort McMurray wildfire.
Only three of those 30 Alberta studies used population-based research. Others examined particular groups or followed earlier samples. Several Fort McMurray papers reused the same datasets, including overlapping groups of students and clinical populations.
The result is a dense cluster of evidence around one community and thin coverage elsewhere. Quebec accounted for another 15 studies. Saskatchewan and Manitoba had no studies capturing mental-health effects, despite their exposure to flooding, extreme heat and ecosystem change. The review also flags flooding, sea-level rise and coastal erosion as Atlantic vulnerabilities requiring study.
Even within the studies that exist, the measures do not line up neatly. Reported depression ranged from 5.2% to 53.7%. Anxiety ranged from 12.5% to 63%. PTSD ranged from 10.2% to 60%. Those spans combine different populations, levels of exposure, survey instruments and time periods. Few studies were population-based, and most were cross-sectional.
The review was designed to map associations, not prove that a climate event caused a particular diagnosis. The authors say longitudinal and quasi-experimental research would be needed to isolate those effects more reliably.
This does not erase what the studies recorded. It defines its limits.
What Happens Between the Event and the Diagnosis
The review did not treat fire, water or heat as the whole mechanism. It traced the conditions that followed them.
After wildfires, the recurring factors included evacuation, relocation, unemployment, inadequate support, media exposure and witnessing buildings burn. After floods, the record included property damage, unemployment, elevated anxiety and the accumulation of other traumas. Across the literature, the most common exposure factors were evacuation, destruction of a home, disruption of livelihoods and cultural activities, social and welfare problems, and re-traumatization.
The consequences also varied by population.
Seventeen studies examined adolescents or youth. They documented climate anxiety and despair, along with PTSD, depression, substance misuse and suicidal thinking after wildfires. Fourteen studies examined people with pre-existing mental-health conditions. The review found they faced heightened risks of worsening depression, anxiety and PTSD after different climate events.
Sixteen studies included Indigenous communities. Their evidence was mostly qualitative. Participants described changes in food security, local knowledge, landscapes, safe travel and cultural activities such as hunting and spending time on the land. The review connects those disruptions to livelihoods and cultural identity, but notes that quantitative information on mental-health outcomes was scarce.
That imbalance is its own finding. Canada has accumulated detailed survey results from repeated disasters in Fort McMurray. It has far less measured evidence for communities experiencing slow changes to land, food and cultural continuity.
The Missing Intervention Record
The review found more evidence describing harm than testing what reduces it.
Its authors call for research on early intervention and support in disaster-affected communities. They identify immediate psychological first aid, long-term resilience strategies, accessible counselling, community-based trauma care and culturally safe spaces as areas requiring attention. They also call for targeted work involving immigrants and refugees, visible minorities, people with chronic illness and people with disabilities, groups largely missing from the existing literature.
The evidence base has grown quickly. Only one included study was published before 2000. Forty-one appeared between 2019 and 2024.
The number of papers grew faster than the map. A national literature can contain 72 studies and still depend heavily on one city, one disaster and, in some cases, the same respondents.
Fort McMurray shows why the research matters. More than three years after the 2016 evacuation, student surveys were still recording worsening symptoms. Five years after the fire, adults were still reporting depression, anxiety, PTSD, medication use and counselling.
The rest of the map remains unfinished.
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Source Documents
Lawrason, S. V. C., Khan, S. U., Farrow, A., Lavigne-Robichaud, M., Ellis, C., Amankwah, N., Edjoc, R., & Semchishen, S. N. (2026). Understanding the impact of climate change on mental health from a Canadian perspective: A scoping review. Health Promotion and Chronic Disease Prevention in Canada: Research, Policy and Practice, 46(7/8), 247-275. https://doi.org/10.24095/hpcdp.46.7/8.01