Cognitive enhancers don't improve cognition, function in people with mild cognitive impairment

September 16, 2013, St. Michael's Hospital

Cognitive enhancers—drugs taken to enhance concentration, memory, alertness and moods—do not improve cognition or function in people with mild cognitive impairment in the long term, according to a new study by researchers at St. Michael's Hospital.

In fact, patients on these medications experienced significantly more nausea, diarrhea, vomiting and headaches, according to the study published today in the Canadian Medical Association Journal.

"Our findings do not support the use of cognitive enhancers for mild cognitive impairment," wrote Dr. Andrea Tricco and Dr. Sharon Straus, who are both scientists in the hospital's Li Ka Shing Knowledge Institute. Dr. Straus is also a geriatrician at the hospital.

Mild cognitive impairment is a condition characterized by without significant limitations in everyday activity. Between 3 and 42 per cent of people are diagnosed with the condition each year, about 4.6 million people worldwide. Each year about 3 to 17 per cent of people with mild cognitive impairment will develop dementia, such as Alzheimer's disease. Given the , it's estimated the number of Canadians with dementia will double to more than 1 million in the next 25 years.

It has been hypothesized that cognitive enhancers may delay the onset of dementia. Families and patients are increasingly requesting these drugs even though their efficacy for patients with mild cognitive impairment has not been established. In Canada, cognitive enhancers can be obtained only with special authorization.

Drs. Tricco and Straus conducted a review of existing evidence to understand the efficacy and safety of cognitive enhancers. They looked at eight that compared one of four cognitive enhancers (donepezil, , galantamine or ) to a placebo among patients diagnosed with mild cognitive impairment.

While they found short-term benefits to using these drugs on one cognition scale, there were no long-term effects after about a year and a half. No other benefits were observed on the second cognition scale or on function, behaviour, and mortality. As well, patients on these medications experienced significantly more nausea, diarrhea, vomiting and headaches. One study also found a higher risk of a heart condition known as bradycardia (slow heartbeat) among patients who received .

"Our results do not support the use of cognitive enhancers for patients with mild cognitive impairment," the authors wrote. "These agents were not associated with any benefit and led to an increase in harms. Patients and their families should consider this information when requesting these medications. Similarly, health care decision-makers may not wish to approve the use of these medications for , because these drugs might not be effective and are likely associated with harm."

This study was funded by the Drug Safety and Effectiveness Network/Canadian Institutes of Health Research.

Another St. Michael's study published in the CMAJ in April found no evidence that drugs, herbal products or vitamin supplements help prevent cognitive decline in healthy older adults. That review, led by Dr. Raza Naqvi, a University of Toronto resident, found some evidence that mental exercises, such as computerized memory training programs, might help.

Explore further: No evidence drugs, vitamins, supplements help prevent cognitive decline in healthy older adults

More information: www.cmaj.ca/lookup/doi/10.1503/cmaj.130451

Related Stories

No evidence drugs, vitamins, supplements help prevent cognitive decline in healthy older adults

April 15, 2013
A review of published research has found no evidence that drugs, herbal products or vitamin supplements help prevent cognitive decline in healthy older adults.

Preventing cognitive decline in healthy seniors

April 15, 2013
Cognitive training exercises—or mental exercise—may help prevent cognitive decline in healthy older adults, while evidence for the benefits of pharmacologic substances and exercise is weak, outlines a review published ...

Diabetic retinopathy severity inversely tied to cognition

July 1, 2013
(HealthDay)—For patients with type 2 diabetes, the severity of diabetic retinopathy (DR) is inversely linked to cognitive impairment, according to a study published online April 30 in Diabetes Care.

Cardiac disease linked to higher risk of mental impairment

January 28, 2013
Cardiac disease is associated with increased risk of mild cognitive impairment such as problems with language, thinking and judgment—particularly among women with heart disease, a Mayo Clinic study shows. Known as nonamnestic ...

Research confirms Mediterranean diet is good for the mind

September 3, 2013
The first systematic review of related research confirms a positive impact on cognitive function, but an inconsistent effect on mild cognitive impairment

Gene is marker only for mild cognitive impairment

February 12, 2013
Defying the widely held belief that a specific gene is the biggest risk factor for Alzheimer's disease, two Cornell developmental psychologists and their colleagues report that people with that gene are more likely to develop ...

Recommended for you

New neuron-like cells allow investigation into synthesis of vital cellular components

January 22, 2018
Neuron-like cells created from a readily available cell line have allowed researchers to investigate how the human brain makes a metabolic building block essential for the survival of all living organisms. A team led by researchers ...

Finding unravels nature of cognitive inflexibility in fragile X syndrome

January 22, 2018
Mice with the genetic defect that causes fragile X syndrome (FXS) learn and remember normally, but show an inability to learn new information that contradicts what they initially learned, shows a new study by a team of neuroscientists. ...

Epilepsy linked to brain volume and thickness differences

January 22, 2018
Epilepsy is associated with thickness and volume differences in the grey matter of several brain regions, according to new research led by UCL and the Keck School of Medicine of USC.

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Mauricio
not rated yet Sep 16, 2013
I rated low because the title insinuates that they reviewed all the cognitive enhancers available. They only evaluated 4 pharmaceutical enhancers. There are dozens at least, many of them are natural substances. And many of them work nicely.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.