Sarah Thomson experienced the reality when a burst artery in her brain wiped out her memories of marriage and 13 years of motherhood.
The 32-year-old went into a coma from which she awoke thinking she was 19.
She had no idea who husband Chris and children Michael, 14, Daniel, five, and four-year-old Amy were. She started to dye her hair all colours and, by her confession, act moodily like a teenager.
The ten days she spent in intensive care last November had destroyed 13 years of her life, making her think it was still 1998. Mrs Thomson thought her favourite band the Spice Girls were together, had no memory of the Millennium and didn’t know Michael Jackson had died.
‘When the children came to see me I just had no idea who they were, I thought they were somebody else’s,’ said Mrs Thomson, who lives in Exeter. ‘I kept calling them the wrong names, and had no idea why they were so pleased to see me.