Download This Paper
Preprints with The Lancet is part of SSRN´s First Look, a place where journals identify content of interest prior to publication. Authors have opted in at submission to The Lancet family of journals to post their preprints on Preprints with The Lancet. The usual SSRN checks and a Lancet-specific check for appropriateness and transparency have been applied. Preprints available here are not Lancet publications or necessarily under review with a Lancet journal. These preprints are early stage research papers that have not been peer-reviewed. The findings should not be used for clinical or public health decision making and should not be presented to a lay audience without highlighting that they are preliminary and have not been peer-reviewed. For more information on this collaboration, see the comments published in The Lancet about the trial period, and our decision to make this a permanent offering, or visit The Lancet´s FAQ page, and for any feedback please contact preprints@lancet.com.
Temperature and Mental Health: A Systematic Review and Meta-Analysis
67 Pages Posted: 7 Sep 2021
More...Abstract
Background: The relationship between ambient temperature and mental health outcomes has not been sufficiently synthesised and communicated.
Methods: A systematic search included all original studies on humans until 20/03/2020 examining a relationship between ambient temperatures and mental health outcomes (suicide, hospital attendance for mental disorders, community mental health and emotional wellbeing). Databases WebOfScience, Embase, PsychINFO, and PubMed were searched, alongside a limited search of Google Scholar. The risk of bias for individual studies was assessed using the Newcastle-Ottawa Scale (NOS), while the quality of evidence across studies was assessed using the GRADE approach.
Findings: 123 studies were included in the review, with 19 studies suitable for meta-analysis. Pooled data on suicide rates (7 articles, N=1,805,734) indicate a risk ratio of 1.01 per 1ºC increase in mean temperature (95%CI: 1.00, 1.01), a 1.7% increase (95%CI: 1.1%, 2.3%) in suicide incidence per 1ºC temperature rise (5 articles, N=219,096), and a 6.2% (95%CI: 5.2%, 7.2%) increase for each 2-5ºC temperature rise (3 articles, N=416,976). Hospital attendance for mental disorders was 9.7% higher (95%CI: 7.6%, 11.9%) during heatwaves than non-heatwave periods (3 articles, N=362,086), with a risk ratio of 1.02 (95%CI: 1.01, 1.03) at the 99th temperature percentile compared with the 50th (3 articles, N=532,296). In qualitative synthesis of the literature, higher ambient temperature (including average temperatures, heatwaves and temperature variation) across multiple time windows were positively associated with increases in attempted and completed suicides (78 studies in this category, >3,976,577 suicide events), increased hospital attendance for mental disorders (33 studies, >6,222,993 hospital attendances), and worse outcomes for community mental health and wellbeing (15 studies, >4,875,006 individuals).
Interpretation: Climate change brings increasing ambient temperatures, heatwaves and temperature variation, which are all risk factors for worse mental health outcomes. Health system leaders and policy makers must be adequately prepared. Building resilience to the impacts of increasing temperatures on mental health outcomes in public health and health systems will require equitable and proactive support for those most vulnerable, including individuals with a diagnosable mental disorder, rural populations and those in 'urban heat islands'. Although many LMIC are particularly vulnerable to climate change, only 25 studies were conducted in these regions. More good quality standardised research is required to improve our understanding of the nature, severity, context and modulating factors of these effects.
Funding Statement: RT receives a studentship from the National Institute for Health Research (NIHR) School for Public Health Research (PD-SPH-2015). MBT is partially supported by a donation from Marit Mohn to the Mohn Centre for Children’s Health and Wellbeing. No other external funding contributed to the study or researcher's time.
Declaration of Interests: None to declare.
Keywords: Climate change, ambient temperature, mental health, mental illness, mental wellbeing, suicide
Suggested Citation: Suggested Citation