Their study, in the journal Occupational and Environmental Medicine, suggested a decade of shifts aged the brain by more than six years.
There was some recovery after people stopped working antisocial shifts, but it took five years to return to normal.
Experts say the findings could be important in dementia, as many patients have disrupted sleep.
The body’s internal clock is designed for us to be active in the day and asleep at night.
The damaging effects on the body of working against the body clock, from breast cancer to obesity, are well know
Now a team at the University of Swansea and the University of Toulouse has shown an impact on the mind as well.
Three thousand people in France performed tests of memory, speed of thought and wider cognitive ability.
The brain naturally declines as we age, but the researchers said working antisocial shifts accelerated the process.
Those with more than 10 years of shift work under their belts had the same results as someone six and a half years older.
The good news is that when people in the study quit shift work, their brains did recover. Even if it took five years.