Wildfires and the Mind: How Smoke and Disaster Shape Brain, Body, and Behavior—Especially for People Living With Mental Illness

Why wildfires are different

Wildfire smoke is a complex mix of fine particles (PM₂.₅), gases, metals, and organic compounds that can travel deep into the lungs and enter the bloodstream, reaching the brain. Recent Stanford‑affiliated and NIH‑supported research shows wildfire PM₂.₅ is particularly harmful compared with PM₂.₅ from other sources, with stronger links to neurological disease and overall health burdens.

What happens in the body (and brain)

Biological pathways thought to drive mental and cognitive effects include:

Systemic and neuro‑inflammation: inhaled particles trigger cytokines that can cross the blood–brain barrier.
Direct neural routes: particles may reach the brain via olfactory nerves and through vagal reflexes.
Stress‑axis activation: smoke and disaster stressors stimulate the HPA axis, disrupting sleep, mood, and cognition.
A 2025 EPA risk assessment summarizes these mechanisms and links smoke exposure to neurological morbidity and mental health symptoms.

Short‑term impacts you can measure

During large smoke events, emergency departments see surges in mental‑health visits:

In California’s 2020 fires, each +10 μg/m³ of wildfire‑specific PM₂.₅ was associated with higher ED visits for all mental health conditions (≈+17%), depression (≈+15%), and other mood‑affective disorders (≈+29%) in the week following exposure. Risks were greatest for children, young adults, women, Black and Hispanic patients, and Medicaid enrollees.

Acute smoke exposure has also been tied to hours‑to‑days declines in cognition, consistent with neuroinflammatory effects.

Longer‑term risks

Large cohort data link long‑term wildfire PM₂.₅ to incident dementia, with stronger associations than for non‑wildfire PM₂.₅—suggesting a unique neurotoxic profile of wildfire smoke.

Beyond smoke, disaster exposure itself (evacuation, loss, displacement) raises risks of PTSD, depression, anxiety, and insomnia. Studies from the Fort McMurray wildfires found substantial rates of PTSD and major depression persisting one to five years later.

Why this matters for people with existing mental illness

Individuals managing conditions such as depression, bipolar disorder, schizophrenia, PTSD, or anxiety may be more vulnerable due to:

Physiological sensitivity to air‑pollution stressors (higher hospitalization/ED responsiveness observed for severe mental illness in air‑pollution studies).
Medication and access issues during evacuations (interrupted care, heat/smoke interactions).
Heightened stress reactivity and sleep disruption, which can worsen symptoms or trigger relapse. Evidence syntheses in psychiatric and environmental‑health literature underscore increased hospitalizations with pollution and consistent post‑wildfire elevations of PTSD/depression.

Special populations & equity

Children and adolescents: higher ED visit risks during smoke and notable post‑fire mental‑health burdens.
Pregnancy: Stanford‑affiliated work links smoke episodes to increased preterm birth risk, even when overall air quality meets “good/moderate” standards.
Older adults: elevated dementia risk with wildfire PM₂.₅ exposure.
Low‑income and marginalized communities: bear disproportionate exposure and health burdens during smoke waves.

Practical steps for clinicians, patients, and communities

Reduce exposure

Track AQI and wildfire smoke forecasts; when PM₂.₅ rises, stay indoors, close windows, and run HEPA air purifiers; use well‑fitted N95 respirators if you must go outside. (Prescribed burns—when used judiciously—can reduce the intensity of future megafires and smoke.)

Protect mental health

Plan medication continuity (90‑day supplies; backup contacts), pre‑plan evacuation with treatment notes and crisis lines.
Maintain sleep routines, light physical activity indoors, and tele‑mental health access during smoke days.
After fires, monitor for PTSD, depression, anxiety, and insomnia; screen early and offer stepped‑care supports (including brief digital interventions shown feasible in wildfire‑affected communities).

Policy & systems

Expand clean‑air shelters, HEPA programs for high‑risk households, and community mental‑health surge capacity during smoke seasons—as recommended by recent Stanford policy briefs and reviews.

References

Stanford Annual Review of Resource Economics (2023): comprehensive review of wildfire smoke health effects.
JAMA Neurology (2024/2025): long‑term wildfire PM₂.₅ exposure linked to incident dementia (Kaiser Permanente Southern California cohort).
Harvard/Stanford‑affiliated summary of JAMA Network Open (2025): wildfire PM₂.₅ linked to surges in mental‑health ED visits, with largest effects in youth and marginalized groups.
EPA Risk Assessment (2025): mechanisms for neurological and mental‑health effects from wildfire smoke (vagal, olfactory, inflammatory, gut‑brain).
Scoping/narrative reviews & disaster cohorts: elevated PTSD, depression, anxiety, and insomnia after wildfires (Fort McMurray studies; multi‑study reviews).