Does adolescence really last until 32? Scientists say the brain has five eras

For decades, we have lived with a simple narrative: childhood ends, adolescence begins, and adulthood settles in sometime in our twenties. However, new research suggests that the brain does not follow our cultural timelines (Nature Communications). Adolescence may extend until the age of 32, reshaping what we think we know about growth, maturity, and the in-between years that define modern adulthood.

The research, based on nearly 4,000 brain scans from people aged 90 and below, found that the brain moves through five major phases: childhood (0-9), adolescence (9-32), adulthood (32-66), early ageing (66-83) and late ageing (83+). And at the heart of these phases are four “turning points”, ages nine, 32, 66 and 83, moments where the brain undergoes its most significant shifts.

Why 32 Matters More Than We Thought

The study’s most striking finding is that our brains do not stabilise in our teens or early twenties, as many previously believed. Instead, the most dramatic change comes at 32, when white matter, the brain’s communication network reaches new levels of integrity and connectivity. This is the point at which intelligence, personality, and emotional processing finally plateau. In other words, the turbulence, self-doubt, and shapeshifting identity of your twenties may not be immaturity, they may be biology.

Childhood (0 - 9): The Brain’s Fastest Growth

The early years remain the most explosive period of brain development. Grey and white matter expand rapidly, synapses multiply and disappear at high speed, and the foundations for emotional and cognitive life are laid. By age nine, the first turning point, puberty and early hormonal shifts begin altering the brain’s architecture, paving the way for adolescence.

Adolescence (9 - 32): A Longer, Messier Phase

Traditionally, adolescence was assumed to end between 18 and 20. But the study suggests this phase stretches much longer in Western countries. Puberty may spark adolescence, but the exit point is shaped by culture, environment, and neurobiology making it fluid rather than fixed.

The researchers found that the brain continues reorganizing itself well into the early thirties, with ongoing changes in decision-making, emotional regulation, and identity formation. This prolonged adolescence may also explain why mental health disorders commonly emerge in young adulthood, as the brain remains in a vulnerable, transitional state.

Adulthood (32 - 66): Stability at Last

Once the brain reaches its second major turning point, a long period of stability begins. White matter strengthens, networks become more reliable, and, for the first time since childhood, the brain’s developmental trajectory slows. Intelligence and personality plateau, forming the version of us that tends to remain consistent through midlife.

Early Ageing (66 - 83): Quiet Decline

In this phase, brain regions begin functioning more independently. Connectivity subtly decreases, and factors like dementia and high blood pressure can accelerate decline. Still, the shift is gentler than previously assumed, more reorganization than deterioration.

Late Ageing (83+): The Final Turn

Although data is limited, the findings suggest a continued weakening of connectivity, marking the brain’s last major structural shift. It’s a phase defined more by reduced integration than abrupt decline.

Why This Matters

The biggest implication of the study is psychological: our cultural expectations of when we should “have it all figured out” don not match the brain’s timeline. What we call immaturity, indecision, or drifting may be part of a 20-year neurological transition. The modern pressure to map out careers, stability, and identity by our mid-twenties sits at odds with a brain still rewiring itself.

By reframing adolescence as a longer, more complex phase, the research challenges the shame often attached to late bloomers, career changes in our thirties, or the emotional instability of young adulthood. It also highlights a period of vulnerability and opportunity that policymakers, educators, and mental health professionals may need to recognize.  If the brain does not settle until 32, then perhaps life does not have to either.