Can puzzles really help prevent dementia?
You've probably seen the headlines: "Do crosswords every day and never get Alzheimer's!" The reality is messier — but more interesting. Here's what the research actually shows, minus the hype.
The honest answer: it's promising, not proven
No one can say "puzzles prevent dementia" with certainty. But there's real evidence that regular mental activity — including puzzles — is associated with slower cognitive decline and better brain health. The key word is associated. Correlation isn't causation, and researchers are still untangling what's really happening.
That said, the findings are genuinely encouraging. Here's what stands out.
What the research actually found
9–11% lower dementia risk
A 10-year study of 10,000+ adults (published in JAMA Network Open) found that people who regularly did puzzles, games, or chess were 9–11% less likely to develop dementia than those who didn't.
2.5 years of delayed decline
Research from the Einstein Aging Study found that crossword puzzlers showed memory decline starting about 2.5 years later than non-puzzlers — even among those who eventually developed dementia.
Better scores across cognitive domains
A study of 19,000 adults (University of Exeter / King's College London) found that frequent puzzle solvers performed better on tests of memory, attention, and reasoning — with sharper scores the more often they played.
The Duke study: crosswords vs. brain games
One of the most interesting recent trials came from Duke and Columbia Universities, published in the New England Journal of Medicine. Researchers compared crossword puzzles against a commercial "brain training" app (Lumosity) in people with mild cognitive impairment.
The takeaway isn't "crosswords are magic." It's that simple, engaging mental activity may be as powerful (or more) than expensive, gamified alternatives — and way more accessible.
Why does this work? (Probably)
The leading theory is cognitive reserve. Think of it like a buffer: the more you exercise your brain, the more capacity you build to handle damage before symptoms appear. Puzzles seem to strengthen neural pathways and possibly even promote new connections.
Working memory workout
Holding rules, patterns, and constraints in mind while solving — that's a real mental rep. Games like NumberGlyph and MemoryGlyph train exactly this.
Attention practice
Short, focused tasks help you practice staying on one thing. In a world of constant distraction, that's valuable.
Pattern recognition
Spotting patterns, eliminating possibilities, updating your mental model — these are executive functions that matter for everyday life.
What puzzles won't do
Time to manage expectations. No puzzle will:
- Cure or reverse Alzheimer's or dementia
- Guarantee you'll never develop cognitive issues
- Replace other important factors (exercise, sleep, social connection, blood pressure management)
The National Academy of Medicine's 162-page report on cognitive aging emphasises that physical activity and blood pressure control have the strongest evidence. Mental activity is "encouraging but inconclusive" — which is honest, not dismissive.
The real win: a habit you'll actually keep
Here's what I keep coming back to: the best brain exercise is the one you'll actually do. Consistently. For years.
That's why I built NumberGlyph and MemoryGlyph to be small and calm. One puzzle. One to three minutes. No streaks to stress about, no gamified pressure. Just a quick daily rep.
Try it yourself
Start with one game. See if you like it. Come back tomorrow.
Sources
Texas A&M (2024) — Study on games, puzzles, and cognitive function in adults with mild cognitive impairment. Read →
Duke University / NEJM Evidence — Crossword puzzles vs. computerised brain games in mild cognitive impairment. Read →
Alzheimer's Drug Discovery Foundation — Overview of puzzle research and cognitive reserve. Read →
Alzheimer's Society (UK) — Study of 19,000 adults on word and number puzzles. Read →
PMC / Einstein Aging Study — Crossword puzzles and memory decline in persons who develop dementia. Read →
Note: This is general information, not medical advice. If you're concerned about memory or cognitive changes, please talk to a doctor. The evidence for brain training is encouraging but still evolving.