City living, stress and mental health

November 12, 2012

City living, stress and mental health

An article in the Daily Mail tells us that people who live in the country are happier and people who live in a city think differently which means they are more likely to suffer mental illness because of this. How they gleaned this information when the German researchers admit that they did not assess participants happiness or stress levels prior to the study, is unknown. The researchers also say that why city dwellers had more active brains requires more study and no conclusions can be drawn from that fact. The researchers openly admit that further research must be conducted before any links between city living and mental illness can be ascertained.

The research was conducted by the University of Heidelberg in Germany and McGill University in Canada and the report was published in the peer reviewed scientific journal ‘Nature’. Funding was provided by the German Federal Ministry of Education and Research, the German Research Foundation and the European Community’s Seventh Framework Programme.

The research team compared participants’ brains for patterns of activity when in stressful situations. The group under investigation was split into two, one section being city dwellers and the others lived in the country. The tests were conducted because previous findings appeared to conclude that there was a link between mental health, schizophrenia and anxiety and mood disorders and the environment people lived in. The findings appeared to indicate that if you were living in an urban situation then you were more likely to suffer from one of the conditions.

The method used to test this theory involved the volunteers being subjected to negative verbal messages and then being asked to complete puzzles while their brains were being scanned. The experimentation found that people who lived in cities had greater activity in the regions of the brain that deal with negative aspects of mood and stress.

Where did the story come from?

The Daily Mail, in addition to wrongly stating that the report found that urban dwellers were more susceptible to mental conditions also wrongly stated that the report found that country dwellers were happier. Other forms of media indicated that the report had actually found evidence that city living caused mental illness. None of these statements whether actually said or just implied can be true because of the design of the study. The study cannot prove cause, it can only record facts. At no time did the researchers investigate or try to measure happiness in any of the study group.

Refreshingly some of the media did get the story right. The Guardian not only reported factually on the findings it also commented the because of the study’s design causality cannot be proven.

What kind of research was this?

Increased risk of many psychological disorders including depression, schizophrenia and anxiety disorders in city dwellers have been indicated in previous studies. This small scale cross sectional study challenged that theory. Use of ‘manufactured’ stress, provided by the researchers in the form of negative feedback and working against the clock, and the monitoring of the participants brains allowed researchers to compare different brains when faced with the same stress issues. These findings could then be compared for people who live in the countryside and others who live in an urban setting.

Although previous findings may indicate a link between city living and an increased risk of mental illness the findings are still inconclusive. There is no research showing how city living can even have this effect. The study investigated how people deal with stress and what areas of the brain were affected by the stress. The study had limitations too; at no time could it ever tell us why the results could have an effect on mental health. What it could do was highlight any differences or similarities between participants when subjected to identical stressful situations. These results could then be compared to look for trends or patterns. No conclusions about mental health could be drawn from any findings.

How was the research carried out?

The experimentation was broken down into three distinct areas. The first experiment generated stress by making the participants work on arithmetic problems against the clock whilst giving them negative feedback through headphones in between the tests. The second experiment gave a similar problem solving scenario but gave negative feedback throughout via a video feed. The final control experiment used another set of problems to be solved, but no additional stress increasing feedback was given.

The levels of stress were monitored by measuring levels of the hormone cortisol. The heart rate and blood pressure of the individuals was also recorded. Additionally all participants had their brains monitored using functional magnetic resonance imaging (fMRI). This can detect activity occurring in each area of the brain. The researchers then recorded patterns of brain activity from the participants. These were then compared between people from different environments.

The third control experiment ensured that brain activity was caused by the stress being induced and not just doing the tests.

The experiments had 32 people, 23 people, and 37 people respectively take part and no one had a mental illnesses or a high risk of mental illness.

The Findings

The experiments all indicated the same patterns of brain activity, showing the areas of the brain associated with social stress situations being consistently activated. There is an area of the brain called the amygdala. This area is related to negative emotions and environmental threats. It is also believed to have an association with anxiety disorders, depression and violent behaviour. Amygdala activity was low in rural dwellers but increased subject to the more urban lifestyles lived by the participants until city dwellers were found having the highest activity.

Country dwellers had the highest activity in another area of the brain which is believed to regulate stress and negative moods.

The previously conducted research which took the view that there may be a link between city living and an increased risk of mental illness was supported by the researchers. They concluded that the increased activity in the amygdala, an area of the brain which is related to negative emotions and environmental threats supported earlier epidemiological research findings.

However the researchers also stated that although increased activity in specific brain regions in response to social stress has been recorded, it cannot be linked to psychological disorders. Further research is required to draw further conclusions, they state. They also reiterate that the study was not designed to study the impact of stress on brain activity, it was only to find that activity. The link between city living and increased risk of mental illness remains tenuous.

Conclusion

The design of the study meant that issues such as; ‘why the brain was active in any certain area?’ or ‘what is the likelihood of developing a mental condition?’ were never going to be answered. The researchers never said or implied anything different. However some members of the media chose to link the results to issues that could not be proven.

The study had defined limits, these were clearly understood by the research team. The study could examine the activity of specific brain regions in response to simulated social stress. The data taken could then be compared to find if brain activity was the same or different for individuals raised in or living in cities and those living in the country. No conclusion can be drawn to why these differences in brain activity occurred. Furthermore any links to mental health problems could not be addressed.

Other points which were unknown included the inability to know if people’s brains changed when they moved living area e.g city to country, or country to city. All of the participants were healthy adult Germans. Stress indications may not be the same for poor, less healthy individuals in a war torn third world country. The study was small scale, less than 100 people took part. All results should be treated with caution because with smaller scale studies the uncertainty of finding increases. By ‘manufacturing’ stress leaves the researchers open to challenge. Whether the brain would behave differently if the individual knew that the situation was real is uncertain.

Trying to discover if there really is a link between city living and higher rates of schizophrenia, anxiety and mood disorders is commendable and could help healthcare and patient wellbeing in the future. However, the identification of a link is yet to be established although this research will prove useful as it may show interactions between a stressful situation and neurological processes. This study does not provide sufficient evidence to prove or disprove the theory that ‘living in an urban environment increases your risk of mental illness’.

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