alzhub.org
Get help now — free helplines

You can call any of these for free. You do not need a diagnosis, an appointment, or a crisis to call — questions and plain exhaustion are reasons enough.

  • Alzheimer's Association 24/7 Helpline 800-272-3900 24 hours a day, 365 days a year Free, confidential support and information for people with dementia, caregivers, families and the public. Master's-level clinicians. Also Spanish.
  • 988 Suicide & Crisis Lifeline 988 24/7 Call or text 988, or chat at 988lifeline.org. For anyone in emotional distress or a mental-health crisis, including caregivers.
  • Alzheimer's Foundation of America (AFA) Helpline 866-232-8484 9:00 am - 9:00 pm ET, seven days a week Licensed social workers providing support, info and referrals. Also text message and web chat. Text: 646-586-5283

In a medical emergency, call 911. More numbers, and what each line does, on the help page.

Home › Research › What the research found › Every row

Every row of the evidence table

One row per finding: what was tested, which way the result went, and how the study was built. The answer by area, and where the studies disagree, are on the main page.

Every row

Filter

Area All 382 Care, carers and services 140 Medicines 85 Genes (not modifiable) 35 All modifiable factors together 27 Diet and supplements 23 Exercise and activity 21 Sleep, mood and social life 19 Hearing and vision 8 Alcohol, tobacco and cannabis 6 Infection and vaccination 5 Heart and metabolic health 4 Injury, delirium and falls 4 Environment 3 Cognitive activity 2
Question Both Prevention 190 Treatment 192
Direction Any Benefit 144 Harm 105 No effect 38 Mixed 37 No direction reported 58
Design Any meta-analysis 57 randomised trial 44 phase 3 trial 15 systematic review 9 phase 2 trial 10 cohort study 136 phase 1 trial 2 cross-sectional study 31 case-control study 14 modelling study 20 regulatory decision 7 company announcement 1 coverage determination 1 None 35
Clear all

Showing 3 of 382 rows for Depression. One row per study per exposure: a study that tested two different things appears twice, once for each.

Scroll the table sideways to see every column.

Research and outcomes, 3 rows. Every row links to its source.
Exposure Question Direction Outcome measured Design People Effect size, as the source reported it Source
Depression Sleep, mood and social life Prevention Harm
why

The authors read these symptoms as early markers of neurodegeneration rather than causes — which is also how an earlier analysis of this same cohort read its own null result for midlife depression.

 Incident dementia over a mean 22.6 years cohort study 5,811 HR 1.29-1.51 for six specific midlife depressive symptoms Lancet Psychiatry 2026
✓ Peer-reviewed PMID 41412145
Depression Sleep, mood and social life Prevention Harm
why

Direction is for having depression (51% higher risk). Treated depression carried lower risk than untreated (HR 0.7), which is the more interesting half but is an observational comparison of people who did and did not get treatment.

 Incident dementia cohort study 354,313 Depression treatment HR 0.7 (95% CI 0.62-0.77) for incident dementia vs untreated depression Biological Psychiatry 2023
✓ Peer-reviewed PMID 36526487
Depression Sleep, mood and social life Prevention No effect
why

Midlife depressive symptoms did not raise dementia risk (HR 1.21, 95% CI 0.95-1.54), even when chronic. The association closer to diagnosis is read by the authors as depression being a prodromal feature, not a cause.

 Incident dementia over 28 years cohort study 10,189 Depressive symptoms at the 2003 ("late-life") assessment: HR 1.72 (95% CI 1.21-2.44) for dementia; chronic/recurring symptoms in the late phase: HR 1.67 (95% CI 1.11-2.49); early-life (1985) depressive symptoms not significant: HR 1.21 (95% CI 0.95-1.54) JAMA Psychiatry 2017
✓ Peer-reviewed PMID 28514478

How this table was built, and where it is weak →