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The Effects of Stress on the Brain (and Why There Was No Lion) at Latitude Festival

22/07/2015 17:51 BST | Updated 22/07/2016 10:59 BST

People always want to know about stress and how it affects their life. There were ample opportunities this week at the Latitude Festival, where Salon London together with the Wellcome Trust organised two events during which I was asked to talk about the effects of stress on the brain. As usual, people had a surprisingly good level of knowledge on these topics, and were prepared to resonate emotionally with the research findings and to bring their own personal experiences into the open through insightful questions. It was great fun and very rewarding.

So, how does stress affect the brain? We seem to forget - certainly the audience was surprised to hear - that the stress response is an automatic survival response, designed to save our lives during life-threatening situations. It's not helpful if you are having a row in the office, you have missed a deadline, or you have a thousand unopened emails in your inbox. It is very helpful, however, if you encounter a lion. Hundreds of years of evolution have not changed our stress response much.

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An Indian lion in the Sasan-Gir National Park in Gujarat. Photo by Carmine Pariante.

I, myself, was stressed. There I was, interviewed by the writer, Helen Bagnall, in front of an audience of all ages lying relaxed on the floor of a big tent, and I did not know if I was going to say something boring, or annoying, or upsetting. This was quite a stressful contemplation.

So, I started by describing my stress response. My breathing was rapid. My heart was racing. My skin was sweating. My pupils were dilated. The adrenaline and the cortisol were raised in my blood. My immune system was activated. Of course, none of these changes were helpful during my public performance: it was all about getting oxygen and sugar to my muscles, increase my vision, and protect me from infections. But they would have been helpful if I had to fight for my life or run to safety - if the tent had been full of lions. And this is what people in the audience really struggled to accept. How it is possible that years of evolution have not really changed our stress response? As far as stress is concerned, are we all still cavemen and cavewomen?

Then came the question: how do all these changes affect the brain? And this is difficult to answer without sounding negative about stress. Actually, everything is all right if the stress response lasts minutes or hours. You have killed the lion, or you have escaped the lion, or you are dead. And your brain would not have changed much as a result (unless you are dead). But what happens when you live in an environment full of lions? And when your stress response never shuts down?

We have shown in our laboratory that stress lasting days or weeks leads to a reduction in the birth of new brain cells (neurogenesis), which on the surface sounds bad, right? But actually, the net effect of this process is that our brain becomes more reactive to stress, so that we can react to each new stressor - to each new lion - sooner and more intensively. If I were a caveman in a high-predator environment, this would save my life. But if there are no lions, it can lead me to depression.

Some studies in clinical samples confirm this. As adults, children exposed to early life trauma (and, indeed, offspring of mothers who were exposed to severe, chronic stress in pregnancy) have an increased stress response, even if they are no longer exposed to stressors later in life; and they are also at increased risk of becoming depressed.

This left the audience baffled. Is this a predisposition that cannot be changed? How can people who have experienced early life trauma look after their mental health and alter this trajectory? Indeed, what can be done to prevent depression in general, or to stop depression at the start?

With the on-stage help of Helen Bagnall and later of Clare Edwards, a coach who specialises in emotional intelligence, we explored the options available in everyday life, and the usual suspects came up: increasing physical exercise, nurturing social support, being mindful and present to your internal and external life, working efficiently and healthily, and limiting information overload ('infobesity' and 'infoxication' are the new enemies; go on an information diet instead, away from your screen). I told a story: a few days earlier I was at a pop up restaurant in Peckham and three people at the table (in their 30s) had all just left social media, as a new life choice.

Mindfulness, unsurprisingly, attracted a lot of attention. Be present to yourself when you are happy and the warmth will remain with you for days; be present to yourself when you are sad and you will manage to understand and elaborate your emotions; and do a reality check if you are not sure of what is going on. And this is when I talked again about the lion.

Because, really, there was no lion. There was no lion in the tent and this made my stress response a little bit useless. But, by acknowledging this, I brought the stress under control. We all encounter problems: difficult, emotional, or sometime tragic problems - with bosses, colleagues, partners, friends or relatives. But there is no lion. Unless of course we are truly exposed to violence, war, or terror, to really life-threatening situations. But for most of us, luckily, there is no lion. It is time to recognise this and appraise reality. We can control our stress response. We no longer need to be cavemen.