Look into the childhoods of many super high achievers, from Howard Schultz to Madonna to Eleanor Roosevelt, and you'll notice a common theme: They weren't very happy. In fact, a great many are downright tragic. 

Madonna lost her mother to cancer at age five. Schultz grew up in a tough housing project. Roosevelt's dad drank himself to death. At first this might look like just random anecdotes, but science suggests there is something more to this observation. 

One classic study of 400 high achievers who had at least two biographies written about them (for positive reasons) found that an incredible 75 percent had experienced a difficult childhood.

Psychologists believe the huge over-representation of those who experienced tough times as children among over achievers is likely because of the skills a difficult childhood can teach. 

No one would wish trauma or abuse on any child, but those who do weather these storms tend to learn extreme resilience, an outsize capacity to handle stress and a dismissive attitude to negative feedback. 

And if you're looking for a contemporary example of how this works, look no further than Elon Musk.

How Elon Musk became Elon Musk

In a recent interview with the UK's Sunday Times, Tosca Musk, the younger sister of the Tesla and SpaceX founder, opened up about the difficult childhood they shared. 

Much of the conversation focuses on the younger Musk's current work as a filmmaker and entrepreneur, but she also recalls the mental and physical abuse their mother suffered at the hands of their father.

It's a topic her mother, Maye Musk, covered in her book A Woman Makes a Plan. "I remember that Tosca and Kimbal, who were two and four respectively, would cry in the corner, and Elon, who was five, would hit him on the backs of his knees to try to stop him," she wrote. 

When Maye finally worked up the courage to leave her husband, he chased her through the streets with a knife.

Tosca's memories of her younger years with Elon and their brother Kimbal aren't all negative. She says the siblings were close and recalls roughhousing with her brothers and being beaten repeatedly at Dungeons & Dragons by Elon. 

But it's clear from the interview, Maye Musk's book, and previous interviews given by Elon that all three Musk siblings experienced extremely trying times when they were young.

That could explain a lot about how Elon Musk became Elon Musk. "Coping with stress is a lot like exercise: We become stronger with practice," explained clinical psychologist Meg Jay in The Wall Street Journal. 

She cites research showing that just as people grow inured to physical stressors like cold or exercise, becoming tougher and more tolerant of difficult conditions, they can adapt to psychological stress through exposure. 

"They became less overwhelmed by subsequent difficulties and by their own fight-or-flight arousal," Jay continues.

There is a breaking point for everyone of course, but up to that point what doesn't kill you, really can make you stronger. Which might just explain how Musk can handle challenges, such as engineering a reusable rocket or facing down electric car production chaos, that would reduce most of us to quivering jelly.

How to become more resilient without the trauma

That's not to say abuse or tragedy is ever desirable. Whatever immunity to stress Musk may have won from his difficult childhood, he doubtless carries its scars too. Which leads to an inevitable question about this kind of armchair psychologizing: Who cares? 

Say Musk and others who suffer tremendously as kids really do emerge stronger, what does it matter? It's not like anyone would recommend traumatizing kids to boost their resilience.

That's true, but psychologists insist that studying the processes that children use to overcome severe challenges can suggest ways we can all be more resilient. 

First, while you don't want to traumatize yourself for the sake of greater mental toughness, you do want to challenge yourself. 

"It helps to take on long-form projects that feel like challenges rather than threats. Whether taking up crew or judo, studying for an advanced degree or mastering an instrument, hard things that aren't emotional or unexpected help us practice for those that are," Jay writes.

The Musk siblings clearly leaned on each other to survive the difficult moments in their childhood. Psychologists also recommend this resilience-building technique to everyone. Contrary to those old cowboy movies you might have seen, toughness is a team sport. The more people you have to lean on in difficult times, the more resilient you'll be.

Finally, don't underestimate the importance of the inner battle. Research shows that those who emerge stronger from challenges are those who cheer themselves on and never stop trying to make plans to cope. 

"Resist defeat in your own mind," Kay teaches. "Fighting back on the inside is where battling back on the outside begins."

Childhood trauma is an evil to be avoided at all costs. But cases like the Musk's illustrate that, for some, extreme challenges can build extreme resilience. Whatever your age or background you can use knowledge of that process to be a bit mentally tougher yourself.

Inc