Puzzles can delay symptoms of dementia in the aged, but accelerate them once they begin.
A study suggests that people who do puzzles and crosswords may stave off dementia longer but experience a more rapid decline once the disease sets in.
1,157 people aged over 65 were given a maximum of five points based on how often they engaged in a variety of activities which involved processing information, including listening to the radio or watching TV, reading a book, carrying out a crossword puzzle or jigsaw, or going to a museum.
For each additional point those without a diagnosed cognitive impairment saw a 50% slower decline in their brain function, which was examined through a variety of tests.
But those diagnosed with Alzheimer's saw a 42% faster decline for each point they had accumulated for mental activity.