New research from the University of Cambridge suggests that adolescence extends well into the early 30s, challenging the traditional view that it ends in the late teens or early twenties. The study, published in Nature Communications, analysed brain scans of nearly 4,000 people aged 0 to 90 to map five distinct stages of brain development across the human lifespan.
The researchers identified that adolescence begins around age nine but continues until approximately age 32. During this period, the brain's communication networks become increasingly refined, enabling faster and smoother connections within and across brain regions. This transformation supports the development of stronger cognitive skills but also coincides with a heightened risk of mental health disorders.
From birth to around age nine, the brain undergoes 'network consolidation', where excess synapses are pruned to strengthen active connections. By the end of this first era, cognitive capacity improves, but vulnerability to mental health issues increases. Adulthood then begins around age 32, characterised by stabilised brain architecture and a plateau in intelligence and personality, lasting until about age 65.
After age 65, the brain shows signs of gradual reorganisation, with reduced connectivity and increased compartmentalisation, linked to ageing and conditions like hypertension. The final epoch starts around age 83, marked by a shift from global to local brain connectivity, as people rely more on well-trodden neural pathways.
Lead researcher Dr Alexa Mousley, a Gates Cambridge scholar, said: 'We know the brain's wiring is crucial to our development, but we lack a big picture of how it changes across our lives and why. These eras provide important context for what our brains might be best at, or more vulnerable to, at different stages.' The findings could help explain why some brains develop differently at key points, such as learning difficulties in childhood or dementia in later years.
