Climate change study links warming temperatures to increased suicide risk

Scientists have warned that the rise in global climate temperatures could put our physical health at risk, such as the spread of certain infectious diseases or food shortages.

Now a new study sheds light on the possible implications of climate change for mental health

The study, published in the journal Nature Climate Change on Monday, suggests that when there are abnormally hot temperatures in a month there is also a tendency to have higher suicide rates for this month compared to the suicide rate in the month at normal average temperatures.

Then, using the data to make predictions, the study suggests that suicide rates in the United States and Mexico could increase with each 1 degree Cels "We take a specific place and we take a specific month, and we are comparing the colder versions of this month to warmer versions of this month, and we ask, "Are the suicide rates different during this month?" We are indeed seeing that They are, "said Marshall Burke, an badistant professor in the Department of Earth Sciences at Stanford University and senior author of the study.

" We find a very consistent relationship between the temperature increases, "adds Burke, adding that the results of the study do not suggest that temperature is the only – or most important – factor badociated with suicide.

"Suicide is a very complex phenomenon. This is not yet well understood, and there are many other risk factors beyond the climate that are important for the risk of suicide, "he said.

Suicide was the tenth leading cause of death in the United States. 45,000 people in 2016, according to the Centers for Disease Control and Prevention.

Globally, nearly 800,000 people die by suicide each year, and 78% of suicides worldwide occur in low- and middle-income countries, according to the World

An increase of 1 degree Celsius related to the Increase in suicide rate

The study included data on suicide rates in the United States between 1968 and 2004 from the CDC's National Vital Statistics System, as well as monthly suicide rates. Mexico between 1990 and 2010 of the National Institute of Statistics and Geography.

The researchers compared these data with temperature and precipitation data in US counties from a climate mapping tool called PRISM. They used data on temperature and rainfall in Mexican municipalities from a temperature tracking tool from the University of Delaware.

The researchers badyzed the relationship between temperature and suicide using these monthly data.

They isolated the correlation between temperature and suicide of all the seasonal factors that could influence the data.

The researchers found that an increase of 1 degree Celsius in mean monthly temperature correlated with an increase in the monthly suicide rate of 0.68% in the United States between 1968 and 2004, and 2, 1% in Mexico between 1990 and 2010.

The researchers then used their findings to estimate that, by 2050, climate change could be linked to a total of 14,020 US suicides and 7,460 suicides in excess in Mexico. They then followed the protocol of the coupled model intercomparison project to make these projections.

Next, the researchers examined whether the monthly temperature was also correlated with depressive message patterns on social media containing certain key words such as "depressed", "lonely" or "suicidal". Burke says:

Researchers collected and badyzed more than 622 million Twitter updates in the United States between May 2014 and July 2015. They compared these Twitter messages with their monthly temperature data.

They found that a 1 degree Celsius increase in monthly average temperature increased the likelihood of a Twitter message expressing depressive language of 0.79% in an badysis and 0.36% in another.

The study had some limitations, including that the results showed an badociation only between abnormal temperature increases and suicide rates. More research is needed to determine why this link exists.

One hypothesis suggests that "as economic conditions worsen that could also worsen mental health," Burke said.

He adds that another hypothesis points to the human physiological response to hot.

"Studies suggest that some components of brain chemistry, particularly certain neurotransmitters, are important for both mental health and regulation of the body's internal temperature," says Burke

. a plausible biological link between temperature, thermal regulation and how the brain regulates its own emotion. "For us, a physiological explanation like this fits our data better because we find such a remarkably consistent relationship between all socio-economic groups in the United States," he said. "But we need a lot more research to explore this hypothesis."

"As we face a planet that is warming, we must understand the impact"

Dr. Jonathan Patz, professor and director of the Global Health Institute at the University of Wisconsin-Madison, who did not participate in the new study, pointed to a separate study showing how students live at higher temperatures in Due to the lack of air conditioning during a heat wave they did less well on cognitive tests compared to their peers who lived in air conditioned spaces during a heat wave.

This small study, in which Patz was not involved, included 44 university students who were followed for 12 consecutive days in the summer. of 2016. The study was published this month in the journal PLOS Medicine

"This suggests a biological effect of heat on brain function, even in young, healthy individuals," says Patz. Admissions to Milwaukee found a relationship between warmer temperatures and "intentional self-harm," he added, referring to a study he conducted, which was published in Climatic Change magazine in 2012.

Combined with Nature Climate Change's new findings, "these studies all highlight the likelihood of negative effects on mental health from climate change," he said. According to Dr. Mona Sarfaty, Executive Director of the Medical Society Climate and Health Consortium and Director of the Climate and Health Program at the Center for Climate Change Communication at George Mason University, the rates Americans increased by almost 30% between 1999 and 2016;

"This announcement preceded this research paper," she said of the new study.

She added that the CDC report "does not imagine the possibility that temperature can be a factor"

Yet, "to date, the focus has been clearly on health mental health after the effects of extreme weather events. "People who experience devastating storms are at risk of losing their homes, livelihoods, and even their personal relationships." These experiences can also lead to drug addiction. long-term implications for individuals and families, "she said." The effects on mental health are also significant in children and people with pre-existing mental disorders. "

Previous studies on suicide and temperature did not have the same "rigor" and "attention" as the new study.the many other contributions to suicide, said Dr. Robin Cooper, clinical professor Assistant at the University of California at San Francisco and a founding member of the Climate Psychiatry Alliance, who was not involved in the study.

"A surprising discovery, what I think needs more attention, is that these increases are perceived across socio-economic groups," said Cooper, adding that the projection of The study of future increases in suicide rates is also alarming.

the impact of temperature increases on mental well-being and suicide in particular, and this study is a very important contribution to scientific understanding, "she said." We need to use this information to develop health policies to protect and limit the impact of temperature increases on our communities. "