Globally, over 301 million people live with anxiety disorders, making it the most common group of mental disorders. According to the World Health Organization, as few as 27 per cent of patients receive any treatment, a situation researchers are currently making significant efforts to remedy.
One such researcher is Randriely Merscher Sobreira de Lima, a postdoctoral fellow in McGill’s Department of Psychiatry. She has set out to better understand the role the environment plays in the progression of anxiety and other mental health concerns.
In a recent paper, published in the journal Brain and Behaviour, Sobreira de Lima and her colleagues explored early-life environmental enrichment and its protective role in one’s emotional development.
Environmental enrichment occurs when the brain is stimulated by social or physical surroundings; for example, spending time in nature. This stimulation helps promote synaptogenesis and neuron plasticity, and has been proven to help protect against the effects of stress caused by early life adversity.
Early-life adversity—such as low birth weights, exposure to violence, and economic hardship—is not only common but a known risk factor for psychopathological developments, including depression, anxiety, and cognitive development disorders.
“This first study […] was to try to mimic the early life stress in an animal model to analyze if exposure to environmental enrichment could improve the development of the animals after stress,” Sobreira de Lima explained in an interview with The Tribune.
In her experiment, rats were randomly separated into two categories. Half of the rats underwent maternal separation on postnatal days 11 and 13 in order to establish early life stress, whereas the other half did not. Following this, each group was further subdivided into two groups, in which half were provided with environmental enrichment, and half were not. In this experiment, environmental enrichment consisted of various toys and objects with differing colours, textures, shapes, and sizes. These rats spent 39 days in their respective environments, after which they were subjected to behavioural tests.
At the end of the study, Sobreira de Lima compared the effects of early life stress and environmental enrichment. The results were shocking.
“Most surprising for me was the lack of effect of this stress exposure,” Sobreira de Lima said.
The environmental enrichment increased explorational behaviours, illustrated through increased time spent exploring habitats—and also reduced anxiety-like behaviours. Nonetheless, there was no consistent effect from maternal deprivation, illustrating the major role personal difference plays in the study of mental health.
“I came from a big family with six siblings adopted, and all of them developed [mental health conditions] related to anxiety,” Sobreira de Lima explained. “So at the beginning, I was really interested to better understand how this stressor or adversity […] could affect individuals through life and how to better manage their symptoms.”
Sobreira de Lima’s work contributes novel insights into effective stress management. Assuming that these correlations hold true for humans, they help to paint a better picture of how to combat anxiety. Therefore, activities such as physical exercise and social interactions in our daily lives are key to managing stress and improving emotional well-being.
This experiment also raised more questions that pertain to Sobreira de Lima’s ongoing work.
“Considering this variation in susceptibility and resilience to mental health disorder after the stress exposure is something really important for humans, […] that’s something that I’m working on right now,” Sobreira de Lima explained.
In her current role at McGill’s Meaney Lab, Sobreira de Lima and her supervisor, Dr. Patrícia Pelufo Silveira, are working to find ways to directly apply their research to humans.
“At McGill, instead of using rats, I’m using mice. And instead of using stress exposure, I’m focusing only on environmental enrichment,” Sobreira de Lima said.
Sobreira de Lima aims to improve preventative measures and refine solutions for people with conditions such as anxiety.
“[I’m] trying to identify […] the molecular basis for resilience so we could focus more on individuals that are resilient or vulnerable to stress exposure,” Sobreira de Lima said.
Moving forward, Sobreira de Lima will work with both mice and humans, allowing her to fully explore the relationship her team has previously determined and more deeply understand stress-related psychopathological disorders.
