When chronic stress piles up over years – through trauma, loneliness, poverty or illness – it leaves a physical mark on the body, called ‘allostatic load’. Over time, this wear and tear can shrink brain regions involved in memory and mood, making people more vulnerable to mental illness.

The encouraging news is that resilience isn’t fixed. It can be strengthened at any age. Regular exercise, good sleep, an anti-inflammatory diet, strong social connections and stress-reduction practices like mindfulness or yoga all can protect the brain. So does a sense of purpose and social connection: people who feel their lives have meaning and feel supported and connected tend to fair better under stress, and recover more easily from setbacks.

Lavretsky’s team also highlights two less familiar ideas: ‘eudaimonia’ and human flourishing through meaningful engagement, and wisdom, which includes empathy, self-reflection and emotional balance. Both appear to grow naturally with age and act as buffers against loneliness and overall decline.

Looking ahead, Lavretsky and her colleagues see promise in new technologies, from wearable stress trackers to AI tools that can flag early warning signs of mental health problems. But they’re careful to note that technology should support human connection, not replace it.

Ultimately, the team calls for brain health to become a public health priority – woven into schools, workplaces and healthcare systems – so that resilience is built long before problems begin in order to prevent brain disorders across the lifespan.