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In people with mild cognitive impairment, cholinesterase inhibitors do not prevent dementia

Cooper C, Li R, Lyketsos C, Livingston G. Treatment for mild cognitive impairment: systematic review. Br J Psychiatry. 2013;203:255-64.

Review question

In people with mild cognitive impairment, can treatment prevent dementia or improve cognitive function (e.g., thinking, learning, and remembering)?


Mild cognitive impairment includes problems with thinking, memory, language, and judgment that are noticeable but don’t much affect daily living. Dementia is cognitive impairment that is serious enough to interfere with daily living.

How the review was done

The researchers did a systematic review, searching for studies that were published up to January 2013. They found 42 randomized controlled trials with 7803 patients.

The key features of the studies were as follows:

  • All people had mild cognitive impairment.
  • Treatments included cholinesterase inhibitors (e.g., donepezil, galantamine, or rivastigmine), nonsteroidal anti-inflammatory drugs (triflusal and rofecoxib), ginkgo biloba, vitamin E, B vitamins, omega-3 polyunsaturated fatty acids, exercise, group psychological therapy (e.g., memory training, relaxation, education), and computer-assisted cognitive training (e.g., matching sentences with pictures on computers).
  • Treatments were usually compared with placebo.
  • Outcomes were cognitive function and dementia.

What the researchers found

A summary of the main study outcomes is shown below. Results for the main outcomes of studies are usually more reliable than for other outcomes.

Treatments for preventing dementia

  • Cholinesterase inhibitors, vitamin E, or gingko biloba did not prevent dementia.
  • People taking rofecoxib were more likely to get dementia than those taking placebo.
  • No studies looked at whether other treatments prevented dementia.

Treatments for improving cognitive function

  • Cholinesterase inhibitors improved cognitive function by a small amount in 1 study but not in 2 other studies.
  • Ginkgo biloba and 6 weeks of group psychological therapy each improved cognitive function, but the evidence was inconsistent or of low quality.
  • Triflusal and B vitamins did not improve cognitive function.
  • Moderate-intensity exercise did not improve cognitive function more than low-intensity exercise.
  • Omega-3 polyunsaturated fatty acids, 6 months of group psychological therapy, and computer-assisted cognitive training were tested in only a small number of people.


In people with mild cognitive impairment, cholinesterase inhibitors do not prevent dementia. There isn’t enough evidence to know if other treatments affect dementia or cognitive function.

Treatments vs control (placebo, usual care, or no treatment) for mild cognitive impairment


Effect on cognitive function

Effect on dementia

Cholinesterase inhibitors

Small improvement in 1 trial. No effect in 2 trials.

No effect in 4 trials.

Nonsteroidal anti-inflammatory drugs

No effect with triflusal in 1 trial.

Rofecoxib increased risk in 1 trial.

Ginkgo biloba

Improved in 1 trial.

No effect in 1 trial.

Vitamin E

Not studied.

No effect in 1 trial.

B vitamins

No effect in 1 trial.

Not studied.

6 weeks of group psychological therapy

Improved in 1 trial.

Not studied.

Moderate-intensity exercise*

No effect in 1 trial.

Not studied.

*Compared with low-intensity exercise.


Cognitive function
Mental processes, including thinking, learning and remembering.
Cognitive impairment
Trouble remembering, learning new things, concentrating, or making decisions that affect everyday life.
A harmless, inactive, and simulated treatment.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

Related Web Resources

  • Alzheimer's Disease: Do Ginkgo products help?

    Informed Health Online
    Gingko supplements (240 mg per day) may help reduce symptoms of Alzheimer's disease and enable you to perform daily tasks better. Be aware that gingko could interact with other medications, so talk to your doctor before taking any supplements.
  • Worried about dementia? Here are 5 ways to cut your risk

    Dementia affects millions of people around the world, and there is no current treatment. There are a few ways to lower your risk. Eat a well-balanced diet, exercise, stay social, and limit alcohol and smoking.
  • Memory loss and dementia
    Dementia causes loss of mental ability, mood changes, and trouble with daily activities. Risk factors for heart disease could increase your risk of dementia like smoking, high cholesterol, drinking alcohol, or being overweight.
DISCLAIMER These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (

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