Participating in Alzheimer’s Disease 

Clinical Trials and Studies

 FACT SHEET

Alzheimer’s Disease Education & Referral (ADEAR) Center

A Service of the National Institute on Aging

National Institutes of Health

U.S. Department of Health and Human Services

When Margaret was diagnosed with earlystage Alzheimer’s disease at age 68, she 

wanted to do everything possible to combat 

the disease. She talked with her doctor about 

experimental treatments and clinical trials 

she had heard about in the news and worked 

with the doctor to find a trial that was right 

for her. Margaret appreciated being able to 

talk to experts about Alzheimer’s and felt 

she was doing something that might also 

help her children and grandchildren avoid 

the disease.

T his is an exciting time for 

Alzheimer’s disease clinical 

research. Thanks to advances 

in our understanding of this disease 

and powerful new tools for “seeing” 

and diagnosing it in people, scientists 

are making great strides in identifying 

potential new interventions to help 

diagnose, slow, treat, and someday 

prevent the disease entirely.

But Alzheimer’s research can move 

forward only if people are willing to 

volunteer for clinical trials and studies. 

Before any drug or therapy can be used 

in clinical practice, it must be rigorously 

tested to find out whether it is safe and 

effective in humans. Today, at least 

50,000 volunteers, both with and 

without Alzheimer’s, are urgently 

needed to participate in more than 

175 actively enrolling clinical trials 

and studies in the United States. To 

reach that goal, researchers will 

need to screen at least half a million 

potential volunteers.

This fact sheet describes Alzheimer’s 

disease clinical trials and studies, 

explains their scientific design, and

offers key facts and questions to 

consider about volunteering for 

clinical research.

Comparing Alzheimer’s 

Disease Clinical Trials 

and Studies

Clinical research is medical research 

involving people. It includes clinical 

studies, which use long-term observation 

and analysis in large groups to determine how a disease or condition may 

occur and progress, and clinical trials, 

which test possible interventions to 

diagnose, prevent, treat, and someday 

cure a disease. 
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Clinical studies observe people in

normal settings, with less direct 

intervention than in clinical trials. 

Researchers gather baseline information, group volunteers according 

to broad characteristics, and compare 

changes over time. Studies of 

Alzheimer’s disease may help identify

new possibilities for clinical trials. 

The National Institute on Aging 

(NIA), part of the National Institutes 

of Health (NIH), sponsors several 

major ongoing studies, such as:

n Alzheimer’s Disease Neuroimaging Initiative investigators 

study brain images and biomarkers 

in people with normal cognitive 

aging, mild cognitive impairment 

(MCI)—a disorder that may precede 

Alzheimer’s disease, and earlystage Alzheimer’s to develop better 

indicators of the disease and its 

progression. For example, they 

have found that certain changes 

in biomarkers, like proteins or 

enzymes in blood or cerebrospinal 

fluid, may signal early Alzheimer’s 

and have established a method 

and standard for testing these 

biomarkers.

n Alzheimer’s Disease Genetics 

Studies researchers analyze DNA 

from persons with and without the 

disease to identify genes that may 

be Alzheimer’s risk factors. 

Clinical trials test interventions 

such as drugs or devices, as well 

as prevention methods and changes 

in diet or lifestyle. (See examples 

below.) Drug testing is the focus of 

many clinical trials. Currently, more

than 90 drugs are in clinical trials for

Alzheimer’s disease, and more are in 

the pipeline awaiting U.S. Food and 

Drug Administration (FDA) approval 

to enter human testing. 

FDA-approved clinical trials are always

preceded by laboratory analyses in test 

tubes and in tissue culture, followed 

by studies in laboratory animals to 

test for safety and efficacy. If these

show favorable results, the FDA 

gives approval for the treatment or 

intervention to be tested in humans.

Clinical trials advance through four

well-defined phases to test the treatment, find appropriate dosage, and 

monitor side effects in increasing 

numbers of people. If investigators 

find an intervention safe and effective 

after undergoing the first three phases,

the FDA decides whether to approve 

it for clinical use. In Phase IV, the 

FDA continues to monitor the effects 

of a new drug after its approval for

marketing and clinical use. If problems

occur, approval may be withdrawn 

and the drug recalled. After the efficacy 

of a drug for one health condition is

established, Phase IV studies can 

evaluate the activity of the drug in 

other conditions.

Clinical Trials Seek Answers

Through Rigorous Testing

Scientists conducting Alzheimer’s 

disease research test a theory by using 

the classic scientific method. They 

first identify a valid question related 

to Alzheimer’s. The question is posed 

as a hypothesis that is either proven 

or disproven by the clinical trial. 
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For example, research has linked high 

blood cholesterol with Alzheimer’s 

disease. Scientists asked: Will medications that lower cholesterol also have

an effect on Alzheimer’s disease? They 

formed a hypothesis: IF reducing blood 

cholesterol has a beneficial effect on 

Alzheimer’s disease, THEN statins 

(drugs to reduce cholesterol) will 

slow the progression of Alzheimer’s 

disease. To test that hypothesis, NIA 

has funded a number of clinical trials, 

which are ongoing.

Why Placebos Are Important

The “gold standard” for testing 

interventions in people is the 

randomized, placebo-controlled 

clinical trial, because it is designed 

to reduce error or bias. Volunteers 

are randomly assigned—that is, 

selected by chance—to either a test 

group receiving the experimental 

intervention or a control group receiving a placebo, an inactive substance 

resembling the drug tested. 

Comparing results indicates whether 

changes in the test group result from 

the treatment. In many trials, no one— 

not even the research team—knows 

who gets the treatment, the placebo, 

or another intervention. When the 

participant, family members, and staff 

all are “blind” to the treatment, the 

study is called a double-blind, placebocontrolled clinical trial.

Placebo and test groups are equally 

important, as shown in the results of 

numerous clinical trials. For example, 

early research suggested that ginkgo 

biloba, an herbal supplement, might 

be effective in delaying dementia. 

To find out, NIA sponsored a 6-year, 

Phase III clinical trial with more 

than 3,000 participants age 75 and 

older. In 2008, scientists reported 

no significant differences in effect 

on dementia in adults who received 

ginkgo biloba or placebo.

This result was disappointing, 

but scientists gained a wealth of 

information to inform future research. 

For example, researchers learned 

more about subgroups of participants 

who may be at greater risk for 

developing dementia, and ginkgo’s 

possible effects on cardiovascular 

disease, cancer, depression, and other 

age-related conditions. They also 

gained insights on issues related to the 

design and conduct of large dementia 

prevention trials in older adults, such 

as the number of participants needed 

to provide clinically significant measures 

on outcomes like occurrence of 

dementia.

Benefits of Volunteering 

n Help others, including future 

family generations, who may be 

at risk for Alzheimer’s disease

n Receive regular monitoring by 

Alzheimer’s professionals

n Learn more about the disease 

from experts

n Get information about support 

groups and resources
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Participating in a Trial or 

Study

How Can People Find Out About 

Alzheimer’s Disease Trials and 

Studies? 

Information about Alzheimer’s disease 

clinical trials and studies is available 

through a number of sources. First, 

talk to your doctor, who may know 

about local or specific research studies

that may be right for you. NIAsupported Alzheimer’s Disease 

Centers or specialized memory or 

neurological clinics in your community 

may also be conducting trials. You 

might also learn of clinical trials 

through newspapers or other media. 

To search more widely for trials or 

studies, you can also visit websites 

like ClinicalTrials.gov or the NIA 

Alzheimer’s Disease Education and 

Referral (ADEAR) Center clinical 

trials database. See the “For More 

Information” section at the end of 

this fact sheet for resources and 

contact information.

What Happens When a Person 

Joins a Clinical Trial?

First, it is important to learn as much

as you can about the trial. Staff 

members at the research center 

are trained to explain the trial in 

detail and describe possible risks and 

benefits. They clarify participants’ 

rights. Participants and their families 

can have this information repeated 

until they are sure they understand it.

After questions are answered, participants sign an informed consent 

form, which contains key facts about 

the trial. Next, they are screened 

Steps in Clinical Trial 

Participation

1. After initial phone screening, 

interested persons go to the 

study site.

2. Staff members explain the trial 

and gather more information. 

3. The participant or proxy signs 

an informed consent.

4. The participant undergoes a 

screening process that indicates 

whether he or she qualifies for 

the trial.

5. A first visit (called the “baseline”

visit) is scheduled, in which 

cognitive and/or physical tests 

may be administered.

6. Selected participants are 

randomly assigned to distinct 

treatment groups.

7. Participants and family members 

follow the trial protocol and 

report any issues or concerns 

to researchers. 

8. They may visit the research 

site for new cognitive, physical, 

or other evaluations and for 

discussions with staff.

9. Investigators collect information

on effects of the intervention, 

disease progression, and the 

safety and well-being of the 

participant and caregiver. 

10. The participant continues to

see his or her regular physician 

for usual health care.
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by clinical staff to see whether they

meet criteria to participate in 

the trial. Screening examines the 

characteristics people must have 

to participate in a particular trial, 

as well as characteristics that may 

exclude them. The screening may 

involve cognitive and physical tests 

that provide baseline information 

to compare with future changes. If 

participants meet all criteria, they are 

enrolled in the trial. 

Informed Consent

Each participant must sign an 

informed consent agreement, affirming 

that he or she understands the trial 

and is willing to participate. Laws 

and regulations regarding informed 

consent differ across States and 

institutions, but they are all meant 

to ensure participant safety and 

protection, and to prevent unethical 

experimentation on vulnerable 

populations.

Researchers conducting clinical 

Alzheimer’s research must consider 

the declining memory and cognitive 

abilities of people with this disease or 

another dementia and must evaluate 

their ability to understand and 

consent to participate in research. 

If the person with Alzheimer’s is 

deemed unable to provide informed 

consent because of problems with 

memory and confusion, an authorized 

legal representative, or proxy (usually 

a family member), may be able to give

permission for the person to participate, particularly if it is included in 

the patient’s durable power of attorney. 

A durable power of attorney is a legal

agreement designating who will 

handle the patient’s affairs when he 

or she no longer can. NIA’s Legal 

and Financial Planning for People 

with Alzheimer’s Disease Fact Sheet 

(available at www.nia.nih.gov/

Alzheimers/Publications/legaltips.htm) 

provides more information.

Inclusion and Exclusion Criteria

In the experimental protocol (written 

research plan), researchers define the 

inclusion criteria volunteers must 

meet to participate, such as age range,

stage of dementia, racial and/or ethnic 

group, gender, genetic profile, and 

family history. The protocol also 

defines exclusion criteria, such as 

health conditions or medications 

that prevent volunteers from joining

a trial. Many volunteers are needed for

screening to find enough people for a

study. Generally, volunteers can participate in only one trial or study at a

time. It is important to realize that

different trials have different inclusion

and exclusion criteria, so being excluded

from one trial does not necessarily 

mean exclusion from another.

What Happens During a Trial?

Usually, participants are randomly 

assigned to one of the trial groups. 

People in each group represent 

selected combinations of characteristics (such as age, sex, education, 

or cognitive ability). The test group 

receives the experimental drug or 

intervention. Other groups receive a 

different drug, a placebo, or another 

intervention. 
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Participants and family members 

follow strict instructions and keep 

detailed records. Every so often, 

they visit the research site to receive 

more physical and cognitive exams 

and talk with staff. Investigators 

collect information on the effects of 

the test drug or treatment, evaluate 

disease progression, and see how the 

participant and caregiver are doing.

What Volunteers Need To Know 

The following issues are some of the 

key concerns potential participants 

should consider before deciding 

whether joining a trial or study is 

right for them.

Expectations and motivations.

Single clinical trials and studies 

generally do not have miraculous 

results, and participants may not 

directly benefit. 

Uncertainty. Some people have 

problems because they are not 

permitted to know whether they are 

getting experimental treatment or 

a placebo, or may not know results. 

Can you live with these sorts of 

uncertainties?

Finding the right clinical trial 

or study. Volunteers must meet the 

inclusion and exclusion criteria listed

by researchers. Even if a participant 

is not eligible for one trial or study, 

another may be just right. 

Time commitment and location. 

Clinical trials and studies last days 

to years and may require multiple 

visits to study sites, such as private 

research facilities, teaching hospitals, 

Alzheimer’s research centers, or 

doctors’ offices. How much time and 

travel are you willing and able to 

undertake? 

Risk. Researchers make every effort to 

ensure the safety of participants, but 

all clinical trials have some risk. What 

level of risk are you comfortable with?

Rights of Volunteers 

Clinical trial volunteers have important

rights, including the rights to receive 

clear, complete information and to 

withdraw from a trial anytime. 

Right to Clear Information

Understanding what is involved in 

a clinical trial or study can relieve 

anxiety. Potential volunteers have 

the right to a thorough explanation 

and answers to all of their questions. 

Participants and family members 

can have information repeated and 

explained until they understand it. 

Right To Withdraw

Volunteers can withdraw from a 

trial or study anytime they or their 

physician feels it is in their best 

interests. For example, a new health 

condition in a volunteer may require 

medications that are risky if combined 

with experimental treatments.

Clinical Trials and Studies 

Need All Kinds of People

Clinical trials and studies are a 

partnership between researchers and 

volunteer participants, who work 

together to answer questions about 

humans we can answer in no other 

way. Ensuring that those answers 

are correct requires including 

volunteers of all kinds: men and 

women, African Americans, Latinos, 
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Native Americans, Asian Americans, 

whites, people with Alzheimer’s or a 

family history of the disease, people 

with conditions that may lead to 

Alzheimer’s, and those without the 

disease (controls). 

An intervention may work differently 

in one group than in another. Without

adequate representation of a particular group, questions about safety and 

effectiveness of a treatment in that 

group may remain unanswered. In 

addition to diversity, the number of 

people included in research can affect 

results. Changes or effects seen in 

smaller groups may or may not show 

up significantly in larger groups. 

For More Information

To find out more, talk with your 

healthcare provider or contact NIA’s 

ADEAR Center at 1-800-438-4380. 

Or, visit the ADEAR Center clinical 

trials database at www.nia.nih.gov/

Alzheimers/ResearchInformation/

ClinicalTrials. You can sign up for 

e-mail alerts that identify new 

clinical trials added to the database. 

More information about clinical trials 

is available at www.ClinicalTrials.gov.

Alzheimer’s Disease Trials and 

Studies

Alzheimer’s Disease Education 

and Referral (ADEAR) Center

P.O. Box 8250

Silver Spring, MD 20907-8250

1-800-438-4380 (toll-free) 

www.nia.nih.gov/Alzheimers

The National Institute on Aging’s 

ADEAR Center offers information 

and publications for families, 

Questions To Ask About 

Clinical Trials and Studies 

n What is the purpose? 

n What tests and treatments will 

be given? 

n What are the risks? 

n What side effects might occur? 

n What may happen with/without 

this research? 

n Can I continue with treatments 

for Alzheimer’s and other 

conditions as prescribed by my 

regular doctor?

n How will you keep my doctor 

informed about my participation 

in the trial?

n Does the study compare standard 

and experimental treatments? 

n How long will it last? How much 

time will it take?

n Where and when will the testing 

occur? 

n How much flexibility will I have? 

n How will it affect my activities?

n If I withdraw, will this affect my 

normal care?

n Will I learn the results?

n Could I receive a placebo?

n What steps ensure my 

confidentiality?

n Are expenses reimbursed?

n Will I be paid?
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caregivers, and professionals on 

Alzheimer’s disease research, 

diagnosis, treatment, patient care, 

caregiver needs, long-term care, and 

education and training. Staff members 

answer telephone, e-mail, and written 

requests and make referrals to local 

and national resources, including 

clinical trials and studies. The ADEAR 

website offers a searchable database 

of Alzheimer’s clinical trials and 

studies (www.nia.nih.gov/Alzheimers/

ResearchInformation/ClinicalTrials), 

as well as free, online publications in 

English and Spanish; e-mail alert and 

online newsletter subscriptions; the 

Alzheimer’s Disease Library (AD Lib) 

database; and more. 

Alzheimer’s Association

225 North Michigan Avenue, Floor 17

Chicago, IL 60601-7633

1-800-272-3900 (toll-free) 

www.alz.org

The Alzheimer’s Association is a 

national, nonprofit organization with

a network of local chapters that provide

education, support, and referrals to 

local resources and services for people 

diagnosed with Alzheimer’s disease, 

their families, and caregivers. The 

Association also funds Alzheimer’s 

research.

Alzheimer’s Disease Cooperative 

Study (ADCS)

www.adcs.org

The ADCS, funded by the National 

Institute on Aging, is a consortium of 

medical research centers and clinics 

working to develop and test drugs to 

treat Alzheimer’s disease.

General Information About 

Research Participation

ClinicalTrials.gov

www.ClinicalTrials.gov

ClinicalTrials.gov is a comprehensive, 

searchable online registry of federally 

and privately funded clinical trials and 

studies.

U.S. Food and Drug Administration

(FDA)

www.fda.gov/ForConsumers/

ByAudience/ForPatientAdvocates/

ParticipatinginClinicalTrials/

The FDA regulates all U.S. clinical 

trials of drugs and devices and offers 

information and resources for clinical 

trials participants and professionals.

Center for Information and Study

on Clinical Research Participation 

(CISCRP)

www.ciscrp.org

www.smartparticipant.org

CISCRP is an independent, national 

nonprofit organization working 

to promote greater understanding 

and awareness of clinical research 

participation and the role it plays in 

public health.

Project IMPACT (Increase 

Minority Participation and 

Awareness of Clinical Trials)

www.impact.nmanet.org

Project IMPACT, an initiative of the

National Medical Association, seeks

to increase awareness and participation of African Americans and other 

minorities in clinical trials and research.

NIH Publication No. 09-7484 September 2009