For 20 years I’ve sat in my therapy room and listened to people. I’ve heard hundreds of stories from childhood that have led to lives of pain and limitation. Some are what you’d expect – abuse, trauma and deprivation – but many are much more mundane. Can a bad first day at school really lead to a fear of failure? Can a single moment of rejection lead to serial relationship disasters? It certainly seems so.

Yet for every childhood sufferer of trauma who still bears the scars as an adult, there’s an adult for whom trauma has led to a life of meaning and achievement. Until its sad demise I worked as a therapist with Kids Company, a charity that helped vulnerable young people. As a consequence, I’ve often seen young people dragging themselves out of a routine of deprivation to pursue a better life with a resilience that left me breathless.

I’ve often seen young people dragging themselves out of deprivation towards a better life

While in my Harley Street practice, I sometimes see clients who’ve lived a life of privilege who remain stuck in a gilded prison that only their thoughts have created. It doesn’t seem to be what happens to us that defines us anywhere near as much, or as often, as the meaning we give it. If what we make of life is the result of our interpretations, how can we guide ourselves and our children towards a positive understanding of an event rather than a negative one? How can we choose an interpretation that causes us to open up to the world and its possibilities rather than shut ourselves off?

If we take one of our cells and put it in a Petri dish with a source of nutrient, it will move towards the nutrient. If you replace the nutrient with a toxin, the cell will move away. In other words, the cell moves towards an opportunity for growth, or it recognises and responds to a need for protection.

As a collection of a trillion cells, I suggest we do the same thing. Freud described this as the pleasure principle – that we all move towards pleasure and away from pain. From day one on this planet your brain has been interpreting your experiences, using them to predict the way the world works and what is going to happen to you moment to moment.

Your brain is constantly shuttling backwards into the past to look for relationships between what’s happening to you now and what happened before. It then uses the connections it finds to predict what is likely to happen to you next. What this means is that decisions we make as children, whether it’s about the meanings of our parents shouting at us; or splitting up; or seeming to favour a sibling; or feeling stupid in front of our friends or rejected by them; or humiliated by a teacher, any of these can be the beginning of a chain of interpretations or misinterpretations that lead us unnecessarily into being in a state of protection. In a world where you’re primed for attack, everyone is a possible attacker and threat is contained in every opportunity.

I’m not suggesting that our protection response is wrong. It has played a key role in our survival as a species. Wanting to protect our children is one of the most powerful instincts we have. However, that very strength can cause us to teach our children to fear unnecessarily and even guide them into limiting beliefs about themselves that hold them back their whole life.

What is crucial is to distinguish unnecessary protection from actual threats. It’s about how to let go of the limitations you experience and realise that the more you are able to be in growth, the more opportunities you’re likely to have to thrive.

Grow! by Trevor Silvester is published by Coronet at £14.99. To order a copy for £12.74, visit bookshop.theguardian.com