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Towards responsible use of cognitive-
enhancing drugs by the healthy
Society must respond to the growing demand for cognitive enhancement. That response must start by
rejecting the idea that ‘enhancement’ is a dirty word, argue
Henry Greely and colleagues
.
T
oday, on university campuses around
the world, students are striking deals to
buy and sell prescription drugs such as
Adderall and Ritalin — not to get high, but to
get higher grades, to provide an edge over their
fellow students or to increase in some meas-
urable way their capacity for learning. These
transactions are crimes in the United States,
punishable by prison.
Many people see such penalties as appro-
priate, and consider the use of such drugs to
be cheating, unnatural or dangerous. Yet one
survey
1
estimated that almost 7% of students in
US universities have used prescription stimu-
lants in this way, and that on some campuses,
up to 25% of students had used them in the
past year. These students are early adopters of
a trend that is likely to grow, and indications
suggest that they’re not alone
2
.
In this article, we propose actions that will
help society accept the benefits of enhance-
ment, given appropriate research and evolved
regulation. Prescription drugs are regulated as
such not for their enhancing properties but pri-
marily for considerations of safety and potential
abuse. Still, cognitive enhancement has much
to offer individuals and society, and a proper
societal response will involve making enhance-
ments available while managing their risks.
Paths to enhancement
Many of the medications used to treat psychi-
atric and neurological conditions also improve
the performance of the healthy. The drugs most
commonly used for cognitive enhancement at
present are stimulants, namely Ritalin (methy-
phenidate) and Adderall (mixed amphetamine
salts), and are prescribed mainly for the treat-
ment of attention deficit hyperactivity disorder
(ADHD). Because of their effects on the cat-
echolamine system, these drugs increase exec-
utive functions in patients and most healthy
normal people, improving their abilities to
focus their attention, manipulate information
in working memory and flexibly control their
responses
3
. These drugs are widely used thera-
peutically. With rates of ADHD in the range of
4–7% among US college students using DSM
criteria
4
, and stimulant medication the stand-
ard therapy, there are plenty of these drugs on
campus to divert to enhancement use.
A newer drug, modafinil (Provigil), has also
shown enhancement potential. Modafinil is
approved for the treatment of fatigue caused by
narcolepsy, sleep apnoea and shift-work sleep
disorder. It is currently prescribed off label for a
wide range of neuropsychiatric and other medi-
cal conditions involving fatigue
5
as well as for
healthy people who need to stay alert and awake
when sleep deprived, such as physicians on night
call
6
. In addition, laboratory studies have shown
that modafinil enhances aspects of executive
function in rested healthy adults, particularly
inhibitory control
7
. Unlike Adderall and Rita-
lin, however, modafinil prescriptions are not
common, and the drug is consequently rare on
the college black market. But anecdotal evidence
and a readers’ survey both suggest that adults
sometimes obtain modafinil from their physi-
cians or online for enhancement purposes
2
.
A modest degree of memory enhancement
is possible with the ADHD medications just
mentioned as well as with medications devel-
oped for the treatment of Alzheimer’s disease
such as Aricept (donepezil), which raise levels
of acetylcholine in the brain
8
. Several other
compounds with different pharmacological
actions are in early clinical trials, having shown
positive effects on memory in healthy research
subjects (see, for example, ref. 9). It is too early
to know whether any of these new drugs will
be proven safe and effective, but if one is it will
surely be sought by healthy middle-aged and
elderly people contending with normal age-
related memory decline, as well as by people
of all ages preparing for academic or licensure
examinations.
Favouring innovation
Human ingenuity has given us means of enhanc-
ing our brains through inventions such as writ-
ten language, printing and the Internet. Most
authors of this Commentary are teachers and
strive to enhance the minds of their students,
both by adding substantive information and by
showing them new and better ways to process
that information. And we are all aware of the
abilities to enhance our brains with adequate
exercise, nutrition and sleep. The drugs just
reviewed, along with newer technologies such
as brain stimulation and prosthetic brain chips,
should be viewed in the same general category
as education, good health habits, and informa-
tion technology — ways that our uniquely inno-
vative species tries to improve itself.
Of course, no two enhancements are equiva-
lent in every way, and some of the differences
have moral relevance. For example, the ben-
efits of education require some effort at self-
improvement whereas the benefits of sleep do
not. Enhancing by nutrition involves changing
what we ingest and is therefore invasive in a way
C. GALLAGHER/SPL
Adderall is one of several drugs
increasingly used to enhance
cognitive function.
702
Advance Online Publication|doi:10.1038/456702a|Published online 7 December 2008
COMMENTARY
that reading is not. The opportunity to benefit
from Internet access is less equitably distributed
than the opportunity to benefit from exercise.
Cognitive-enhancing drugs require relatively
little effort, are invasive and for the time being
are not equitably distributed, but none of these
provides reasonable grounds for prohibition.
Drugs may seem distinctive among enhance-
ments in that they bring about their effects by
altering brain function, but in reality so does any
intervention that enhances cognition. Recent
research has identified beneficial neural changes
engendered by exercise
10
, nutrition
11
and sleep
12
,
as well as instruction
13
and reading
14
. In short,
cognitive-enhancing drugs seem morally equiv-
alent to other, more familiar, enhancements.
Many people have doubts about the moral
status of enhancement drugs for reasons rang-
ing from the pragmatic to the philosophical,
including concerns about short-circuiting
personal agency and undermining the value of
human effort
15
. Kass
16
, for example, has written
of the subtle but, in his view, important differ-
ences between human enhancement through
biotechnology and through more traditional
means. Such arguments have been persuasively
rejected (for example, ref. 17). Three arguments
against the use of cognitive enhancement by
the healthy quickly bubble to the surface in
most discussions: that it is cheating, that it is
unnatural and that it amounts to drug abuse.
In the context of sports, pharmacological
performance enhancement is
indeed cheating. But, of course,
it is cheating because it is
against the rules. Any good set
of rules would need to distin-
guish today’s allowed cognitive
enhancements, from private
tutors to double espressos, from the newer
methods, if they are to be banned.
As for an appeal to the ‘natural’, the lives of
almost all living humans are deeply unnatural;
our homes, our clothes and our food — to say
nothing of the medical care we enjoy — bear
little relation to our species’ ‘natural’ state.
Given the many cognitive-enhancing tools we
accept already, from writing to laptop comput-
ers, why draw the line here and say, thus far but
no further?
As for enhancers’ status as drugs, drug abuse
is a major social ill, and both medicinal and
recreational drugs are regulated because of
possible harms to the individual and society.
But drugs are regulated on a scale that subjec-
tively judges the potential for harm from the
very dangerous (heroin) to the relatively harm-
less (caffeine). Given such regulation, the mere
fact that cognitive enhancers are drugs is no
reason to outlaw them.
Based on our considerations, we call for a
presumption that mentally competent adults
should be able to engage in cognitive enhance-
ment using drugs.
Substantive concerns and policy goals
All technologies have risks as well as benefits.
Although we reject the arguments against
enhancement just reviewed, we recognize at
least three substantive ethical concerns.
The first concern is safety. Cognitive enhance-
ments affect the most complex and important
human organ, and the risk of unintended side
effects is therefore both high and consequen-
tial. Although regulations governing medicinal
drugs ensure that they are safe and effective for
their therapeutic indications, there is no equiv-
alent vetting for unregulated ‘off label’ uses,
including enhancement uses. Furthermore,
acceptable safety in this context depends on
the potential benefit. For example, a drug that
restored good cognitive functioning to people
with severe dementia but caused serious adverse
medical events might be deemed safe enough to
prescribe, but these risks would be unacceptable
for healthy individuals seeking enhancement.
Enhancement in children raises additional
issues related to the long-term effects on the
developing brain. Moreover, the possibility of
raising cognitive abilities beyond their spe-
cies-typical upper bound may engender new
classes of side effects. Persistence of unwanted
recollections, for example, has clearly negative
effects on the psyche
18
.
An evidence-based approach
is required to evaluate the
risks and benefits of cogni-
tive enhancement. At a mini-
mum, an adequate policy
should include mechanisms
for the assessment of both risks and benefits for
enhancement uses of drugs and devices, with
special attention to long-term effects on devel-
opment and to the possibility of new types of
side effects unique to enhancement. But such
considerations should not lead to an insist-
ence on higher thresholds than those applied to
medications.
We call for an evidence-based approach to
the evaluation of the risks and benefits of cog-
nitive enhancement.
The second concern is freedom, specifically
freedom from coercion to enhance. Forcible
medication is generally reserved for rare cases in
which individuals are deemed threats to them-
selves or others. In contrast, cognitive enhance-
ment in the form of education is required for
almost all children at some substantial cost to
their liberty, and employers are generally free to
require employees to have certain educational
credentials or to obtain them. Should schools
and employers be allowed to require pharma-
ceutical enhancement as well? And if we answer
‘no’ to this question, could coercion occur indi-
rectly, by the need to compete with enhanced
classmates and colleagues?
Questions of coercion and autonomy are
particularly acute for military personnel and
for children. Soldiers in the United States
and elsewhere have long been offered stimu-
lant medications including amphetamine
and modafinil to enhance alertness, and in
the United States are legally required to take
medications if ordered to for the sake of their
military performance
19
. For similar reasons,
namely the safety of the individual in question
and others who depend on that individual in
dangerous situations, one could imagine other
occupations for which enhancement might be
justifiably required. A hypothetical example is
an extremely safe drug that enabled surgeons
to save more patients. Would it be wrong to
require this drug for risky operations?
Appropriate policy should prohibit coercion
except in specific circumstances for specific
occupations, justified by substantial gains in
safety. It should also discourage indirect coer-
cion. Employers, schools or governments
should not generally require the use of cog-
nitive enhancements. If particular enhance-
ments are shown to be sufficiently safe and
effective, this position might be revisited for
those interventions.
Children once again represent a special case
as they cannot make their own decisions. Com-
parisons between estimates of ADHD preva-
lence and prescription numbers have led some
to suspect that children in certain school dis-
tricts are taking enhancing drugs at the behest
of achievement-oriented parents, or teachers
seeking more orderly classrooms
20
. Govern-
ments may be willing to let competent adults
take certain risks for the sake of enhancement
while restricting the ability to take such risky
decisions on behalf of children.
The third concern is fairness. Consider an
examination that only a certain percentage
can pass. It would seem unfair to allow some,
but not all, students to use cognitive enhance-
ments, akin to allowing some students taking a
maths test to use a calculator while others must
go without. (Mitigating such unfairness may
raise issues of indirect coercion, as discussed
above.) Of course, in some ways, this kind of
unfairness already exists. Differences in edu-
cation, including private tutoring, preparatory
courses and other enriching experiences give
some students an advantage over others.
Whether the cognitive enhancement is
substantially unfair may depend on its avail-
ability, and on the nature of its effects. Does it
actually improve learning or does it just tem-
porarily boost exam performance? In the latter
“We should welcome
new methods of
improving our brain
function.”
703
NATURE|Advance Online Publication|doi:10.1038/456702a|Published online 7 December 2008
OPINION
case it would prevent a valid measure of the
competency of the examinee and would
therefore be unfair. But if it were to enhance
long-term learning, we may be more willing
to accept enhancement. After all, unlike ath-
letic competitions, in many cases cognitive
enhancements are not zero-sum games. Cog-
nitive enhancement, unlike enhancement for
sports competitions, could lead to substantive
improvements in the world.
Fairness in cognitive enhancements has a
dimension beyond the individual. If cognitive
enhancements are costly, they may become the
province of the rich, adding to the educational
advantages they already enjoy. One could miti-
gate this inequity by giving every exam-taker
free access to cognitive enhancements, as some
schools provide computers during exam week
to all students. This would help level the play-
ing field.
Policy governing the use of cognitive
enhancement in competitive situations should
avoid exacerbating socioeconomic inequali-
ties, and should take into account the validity
of enhanced test performance. In developing
policy for this purpose, problems of enforce-
ment must also be considered. In spite of strin-
gent regulation, athletes continue to use, and be
caught using, banned performance-enhancing
drugs.
We call for enforceable policies concern-
ing the use of cognitive-enhancing drugs to
support fairness, protect individuals from
coercion and minimize enhancement-related
socioeconomic disparities.
Maximum benefit, minimum harm
The new methods of cognitive enhance-
ment are ‘disruptive technologies’
that could have a profound
effect on human life in the
twenty-first century. A
laissez-faire approach
to these methods will
leave us at the mercy
of powerful market
forces that are bound
to be unleashed by the
promise of increased
productivity and competi-
tive advantage. The concerns
about safety, freedom and fair-
ness, just reviewed, may well
seem less important than the
attractions of enhancement,
for sellers and users alike.
Motivated by some of the same considera-
tions, Fukuyama
21
has proposed the formation
of new laws and regulatory structures to protect
against the harms of unrestrained biotechno-
logical enhancement. In contrast, we suggest a
policy that is neither laissez-faire nor prima-
rily legislative. We propose to use a variety of
scientific, professional, educational and social
resources, in addition to legislation, to shape
a rational, evidence-based policy informed
by a wide array of relevant experts and stake-
holders. Specifically, we propose four types of
policy mechanism.
The first mechanism is an accelerated
programme of research to build a knowledge
base concerning the usage, benefits and asso-
ciated risks of cognitive enhancements. Good
policy is based on good information, and there
is currently much we do not know about the
short- and long-term benefits and risks of the
cognitive-enhancement drugs currently being
used, and about who is using them and why. For
example, what are the patterns of use outside of
the United States and outside of college commu-
nities? What are the risks of dependence when
used for cognitive enhancement? What special
risks arise with the enhancement of children’s
cognition? How big are the effects of currently
available enhancers? Do they change ‘cogni-
tive style’, as well as increasing how quickly
and accurately we think? And given that most
research so far has focused on simple laboratory
tasks, how do they affect cognition in the real
world? Do they increase the total knowledge
and understanding that students take with
them from a course? How do they affect various
aspects of occupational performance?
We call for a programme of research into the
use and impacts of cognitive-enhancing drugs
by healthy individuals.
The second mechanism is the participa-
tion of relevant professional organizations
in formulating guidelines for their
members in relation to cognitive
enhancement. Many dif-
ferent professions have a
role in dispensing, using
or working with peo-
ple who use cognitive
enhancers. By creating
policy at the level of
professional societies,
it will be informed by
the expertise of these
professionals, and their
commitment to the goals of
their profession.
One group to which this
recommendation applies is
physicians, particularly in
primary care, paediatrics and
psychiatry, who are most likely to be asked for
cognitive enhancers. These physicians are some-
times asked to prescribe for enhancement by
patients who exaggerate or fabricate symptoms
of ADHD, but they also receive frank requests,
as when a patient says “I know I don’t meet diag-
nostic criteria for ADHD, but I sometimes have
trouble concentrating and staying organized,
and it would help me to have some Ritalin on
hand for days when I really need to be on top of
things at work.” Physicians who view medicine
as devoted to healing will view such prescribing
as inappropriate, whereas those who view medi-
cine more broadly as helping patients live better
or achieve their goals would be open to consid-
ering such a request
22
. There is certainly a prec-
edent for this broader view in certain branches
of medicine, including plastic surgery, derma-
tology, sports medicine and fertility medicine.
Because physicians are the gatekeepers to
medications discussed here, society looks to
them for guidance on the use of these medica-
tions and devices, and guidelines from other
professional groups will need to take into
account the gatekeepers’ policies. For this rea-
son, the responsibilities that physicians bear for
the consequences of their decisions are particu-
larly sensitive, being effectively decisions for all
of us. It would therefore be helpful if physicians
as a profession gave serious consideration to
the ethics of appropriate prescribing of cogni-
tive enhancers, and consulted widely as to how
to strike the balance of limits for patient benefit
and protection in a liberal democracy. Exam-
ples of such limits in other areas of enhancement
medicine include the psychological screening of
candidates for cosmetic surgery or tubal ligation,
and upper bounds on maternal age or number
of embryos transferred in fertility treatments.
These examples of limits may not be specified by
law, but rather by professional standards.
Other professional groups to which this
recommendation applies include educators
and human-resource professionals. In differ-
ent ways, each of these professions has respon-
sibility for fostering and evaluating cognitive
performance and for advising individuals who
are seeking to improve their performance, and
some responsibility also for protecting the
interests of those in their charge. In contrast
to physicians, these professionals have direct
conflicts of interest that must be addressed in
whatever guidelines they recommend: liberal
use of cognitive enhancers would be expected
to encourage classroom order and raise stand-
ardized measures of student achievement, both
of which are in the interests of schools; it would
also be expected to promote workplace produc-
tivity, which is in the interests of employers.
Educators, academic admissions officers and
credentials evaluators are normally responsible
for ensuring the validity and integrity of their
examinations, and should be tasked with for-
mulating policies concerning enhancement by
test-takers. Laws pertaining to testing accom-
modations for people with disabilities provide
SPL
The prescription drug Ritalin is
illegally traded among students.
704
NATURE|Advance Online Publication|doi:10.1038/456702a|Published online 7 December 2008
OPINION