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University of Zurich Zurich Open Repository and Archive Winterthurerstr. 190 CH-8057 Zurich http://www.zora.uzh.ch Year: 2010 Ethics of neuroenhancement: a phantom debate. [Book review of: Bettina Schöne-Seifert, Davinia Talbot, Uwe Opolka and Johann S Ach (eds.), Neuro-Enhancement. Ethik vor neuen Herausforderungen, Paderborn: mentis, 2009] Quednow, B B Quednow, B B (2010). Ethics of neuroenhancement: a phantom debate. [Book review of: Bettina Schöne-Seifert, Davinia Talbot, Uwe Opolka and Johann S Ach (eds.), Neuro-Enhancement. Ethik vor neuen Herausforderungen, Paderborn: mentis, 2009]. BioSocieties, 5(1):153-156. Postprint available at: http://www.zora.uzh.ch Posted at the Zurich Open Repository and Archive, University of Zurich. http://www.zora.uzh.ch Originally published at: BioSocieties 2010, 5(1):153-156.

Ethics of neuroenhancement: a phantom debate. [Book review ...€¦ · enhancement, biological and technical brain implants, and genetic manipulations). I will not engage with the

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Page 1: Ethics of neuroenhancement: a phantom debate. [Book review ...€¦ · enhancement, biological and technical brain implants, and genetic manipulations). I will not engage with the

University of ZurichZurich Open Repository and Archive

Winterthurerstr. 190

CH-8057 Zurich

http://www.zora.uzh.ch

Year: 2010

Ethics of neuroenhancement: a phantom debate. [Book reviewof: Bettina Schöne-Seifert, Davinia Talbot, Uwe Opolka andJohann S Ach (eds.), Neuro-Enhancement. Ethik vor neuen

Herausforderungen, Paderborn: mentis, 2009]

Quednow, B B

Quednow, B B (2010). Ethics of neuroenhancement: a phantom debate. [Book review of: Bettina Schöne-Seifert,Davinia Talbot, Uwe Opolka and Johann S Ach (eds.), Neuro-Enhancement. Ethik vor neuen Herausforderungen,Paderborn: mentis, 2009]. BioSocieties, 5(1):153-156.Postprint available at:http://www.zora.uzh.ch

Posted at the Zurich Open Repository and Archive, University of Zurich.http://www.zora.uzh.ch

Originally published at:BioSocieties 2010, 5(1):153-156.

Quednow, B B (2010). Ethics of neuroenhancement: a phantom debate. [Book review of: Bettina Schöne-Seifert,Davinia Talbot, Uwe Opolka and Johann S Ach (eds.), Neuro-Enhancement. Ethik vor neuen Herausforderungen,Paderborn: mentis, 2009]. BioSocieties, 5(1):153-156.Postprint available at:http://www.zora.uzh.ch

Posted at the Zurich Open Repository and Archive, University of Zurich.http://www.zora.uzh.ch

Originally published at:BioSocieties 2010, 5(1):153-156.

Page 2: Ethics of neuroenhancement: a phantom debate. [Book review ...€¦ · enhancement, biological and technical brain implants, and genetic manipulations). I will not engage with the

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Review of Bettina Schöne-Seifert, Davinia Talbot, Uwe Opolka, and Johann S. Ach

(eds.), Neuro-Enhancement. Ethik vor neuen Herausforderungen, Paderborn: mentis,

2009.

Ethics of neuroenhancement: a phantom debate

Boris B. Quednow

University Hospital of Psychiatry,

Division of Experimental and Clinical Pharmacopsychology,

Lenggstr. 31, CH-8032 Zürich, Switzerland

E-mail: [email protected]

With their book Neuro-Enhancement: Ethik vor neuen Herausforderungen, the editors Bettina

Schöne-Seifert, Davinia Talbot, Uwe Opolka, and Johann S. Ach have delivered a collection

of articles providing a cross-section of the ongoing debate over cognitive and mood

enhancement in Germany. As a pharmacopsychologist working on the neurochemistry of

cognition and emotion I have followed this debate for several years now and I have felt

uneasy about it from the start. What follows might rather be a perspectival response to the

presented volume than a classical book review. But considering the current proliferation of

publications on the ethics of neuroenhancement it seems about time to call into question some

of the pharmacological and epidemiological presumptions on which this emergent body of

literature – including the book at hand – is based.

The volume Neuro-Enhancement was developed from papers presented at a one-week

conference organized by the editors at the Hanse-Wissenschaftskolleg in Delmenhorst,

Germany in 2005. All contributors are established experts in the field of medical ethics, but

they come from different disciplines such as philosophy, political science, and medicine. The

chapters are divided into four thematic sections. The first provides a conceptual framework

distinguishing neuroenhancement of healthy subjects from the medical treatment of patients.

Here, Saskia Nagel and Achim Stephan, for example, draw a normative map of conceivable

enhancement options. And Joel Anderson discusses whether the use of imaginable future

neuroprotheses providing music lovers with super hearing would be ethically legitimate. The

second section illustrates the problems and chances of cognitive enhancement in particular.

For instance, Sabine Müller poses the question whether, from idealist and utilitarian

perspectives respectively, the enhancement of intelligence would be morally obligatory – if it

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became possible. The third section reviews issues of emotional enhancement addressing the

challenge posed by drugs such as Prozac to authenticity. And the final section discusses the

ethical implications of neuroenhancement for society at large. As most of the preceding

contributions, Bernward Gesang’s consideration of the social risks and benefits of different

kinds of enhancement or Petra Schaper-Rinkel’s discussion of the political consequences of

thinkable further developments of neuroimplants connecting people in new ways presuppose

that, as the editors put it, neuroenhancement “will actually turn out to be efficient, agreeable

and therefore, from an individual perspective, attractive.”

From a pharmacological point of view, however, this presupposition is questionable.

In my discussion, I will focus on what the book has to say about the enhancement of cognitive

performance (although similar critiques could be developed with respect to emotional

enhancement, biological and technical brain implants, and genetic manipulations). I will not

engage with the ethical, social, and political consequences of enhancement discussed by the

authors (as one could usually expect from a book review) as I believe that already their

pharmacological and epidemiological premises are unrealistic.

Almost all contributions to the volume Neuro-Enhancement are based on the

assumption that, in the near future, we will have access to compounds that are not only

effective cognitive enhancers, but also safe and well-tolerated and therefore suitable to be

taken by everybody (see, for example, the essays of Schaper-Rinkel and Synofzik). This,

however, is not likely to happen in the foreseeable future. It seems that many medical ethicists

have been led astray by exaggerated promises of neuroscientists who are either collaborators

of the pharmaceutical industry or forced to overstate their own results to get increasingly

competitive research funding. As a matter of fact, we are currently even unable to fully restore

disturbed intellectual functioning in psychiatric or neurological diseases and we still do not

know how to achieve this goal in the future.

Let me briefly sum up where we currently stand with respect to cognitive

enhancement. In the discussed book, two drugs are repeatedly referred to as supposedly

effective cognitive enhancers: methylphenidate (Ritalin©, Concerta©), and modafinil

(Provigil ©, Vigil©). Together with amphetamine and the illegal drug cocaine, these

substances share some neurochemical mechanisms and psychotropic effects which justify

calling all of them stimulants. These drugs are affecting the dopamine and noradrenaline

systems and their main effects are an increase of vigilance, arousal, and motivation. But, as

far as we currently know, they have no direct effect on specific cognitive domains such as

memory or executive functions (de Jongh et al., 2008). Thus, stimulants are rather second-

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order cognitive enhancers. For the sake of clarity, they would better be called vigilance or

motivation enhancers. Interestingly, for all of these substances it has been shown that they

increase cognitive performance only in subjects with low baseline capacities whereas in

subjects with higher baseline performance often deteriorates (Mattay et al., 2000; Mattay et

al., 2003; Mehta et al., 2000; Muller et al., 2004; Randall et al., 2005). This points to a

principle brain mechanism that can be found in several neuronal systems and circuits: the

inverse U-function. According to this principle, enhancement is only possible as long as we

do not have an optimal level of arousal, vigilance, or neurotransmitter concentration (Arnsten

& Li, 2005; Kahneman, 1973; Mattay et al., 2003). Hence, an already optimally tuned brain

can hardly be enhanced. Given that usually our brains already perform to the best of their

ability and that the homeostasis of this organ is very sensitive, general enhancement for

everyone seems strictly limited. Against this background, it is not surprising that stimulants –

and here in particular modafinil – are effective to counter cognitive decline caused by sleep

deprivation. It was shown that caffeine – a well-known and effective vigilance enhancer with

tolerable side effects – was about as effective as modafinil to antagonize sleep deprivation-

induced impairments, for example, of reaction time (Killgore et al., 2008; Wesensten et al.,

2002). However, cognitive effects in well-rested healthy subjects are small and hard to detect

(for review see Kumar, 2008).

Moreover, several studies have shown that an increased performance in one cognitive

domain often goes along with a decrease in performance in another domain. For example, we

could enhance our working memory but simultaneously decrease our long-term memory or

vice versa but we will never be able enhance both simultaneously (de Jongh et al., 2008). The

same is true regarding focusing vs. shifting attention and several other cognitive functions.

These phenomena are further complicated by the fact that effects vary between individuals (a

drug may enhance domain X and impair domain Y in individual A, whereas in subject B

domain X is impaired and domain Y is enhanced) (Clatworthy et al., 2009).

Because of the vast complexity of the brain, it seems likely that we will not be able to

overcome trade-offs between enhancement and simultaneous impairment by drugs. Apart

from the collateral adverse effects on cognitive functions, the available substances have many

psychiatric and somatic side effects which make them not well suited for use in healthy

humans only for the purpose of enhancing vigilance or motivation. For example, all

stimulants bear a risk of addiction, which can be explained by their specific mechanism of

action (Berridge, 2007). Thus, I trust in the old pharmacological principle that there is no

effect without a side effect, which is essentially true for all drugs acting on the brain. Our

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brain is of such complexity and its neurotransmitter systems are so strongly interlaced that

turning a small screw in one system generates unpredictable effects in all other systems with

corresponding consequences for behavior. Neuroscience has just scratched the surface of a

still undiscovered universe.

As we have seen there is no genuine cognitive enhancer available to date. There are

several current attempts to develop more specifically acting compounds such as memory

enhancers. However, none of the drugs tested so far have shown replicable and significant

effects in healthy human volunteers (de Jongh et al., 2008; Lanni et al., 2008). Thus, we are

still waiting for an effective drug that enhances cognition at least in patients suffering from

mental dysfunctions. But it seems dubitable whether we will ever see the arrival of drugs

significantly improving cognition in healthy subjects as presupposed in many contributions to

Neuro-Enhancement. Certainly not in the near future.

However, the topicality of the book is not only based on such futurology, but also on

an – equally questionable – diagnosis of the present. In their introduction, Schöne-Seifert and

Talbot argue that already available cognitive enhancers such as methylphenidate and

modafinil are increasingly prescribed beyond their actual indications. They convey a sense of

urgency: “More and more students, professors, and managers are already taking drugs for

neuroenhancement purposes.“ Schaper-Rinkel believes that a market for neuroenhancement is

developing and that its commercial significance will strongly increase in the near future (p.

299).

There is nothing new about such recreational and off-label use of stimulants. From the

1940s to the 1960s, there was an epidemic abuse of amphetamines in countries like the USA,

Great Britain, or Sweden with millions of users. In 1969, shortly before the distribution of

amphetamines was legally restricted, the estimated prevalence of stimulant misuse in the US

was comparable to 2002 (Rasmussen, 2008). Although, at the time, most amphetamines were

sold as mild antidepressants they were also advertised for the enhancement of “mental

alertness” (Rasmussen, 2008). Thus, the supposed urgency of the situation is not due to the

fact that we are facing an unprecedented epidemic.

In fact, the extent of cognitive enhancer abuse today has often been exaggerated (see

the essay of Talbot, p. 325). A frequently cited study reported that up to 13% of high school

students and up to 20% of college students in the US tried methylphenidate (Kapner, 2003).

However, a more recent meta-analysis has shown that the one-year prevalence of experiences

with stimulant cognitive enhancers is only 4% while the lifetime prevalence is 7% (Sussman

et al., 2006). Moreover, the misuse was most prevalent among white male college students

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struggling with their grades and living in larger urban areas (McCabe et al., 2005). These

youth also tend to use illegal drugs such as cannabis, alcohol, MDMA, and cocaine (Sussman

et al., 2006). Interestingly, more than 40% of the students reported that they use

methylphenidate and amphetamine not only for performance enhancement but also to improve

their mood, to get “high”, or for going clubbing (Sussman et al., 2006; Teter et al., 2005). The

misuse of prescription stimulants is highest between 19 and 24 years and then decreases with

increasing age (Johnston et al., 2005). And, finally, the lifetime prevalence of

methylphenidate use in US college students seems to be decreasing rather than increasing,

dropping from 5.7% in 2002 to 3.9% in 2006 (Kapner, 2008). In Germany, in a recent survey

of a big health insurance program, less than 1% of the employees reported that they had used

stimulants at least once in their lives against tiredness and sleepiness (0.93%) or for better

concentration (0.63%) (DAK, 2009). These numbers show that the diagnosed epidemic of

cognitive enhancer abuse is inexistent.

A further result of several surveys was that women prefer the use of antidepressants or

sedative drugs whereas men are more inclined toward the use of stimulants to enhance their

work performance (e.g., DAK, 2009). This phenomenon points to the fact that not everyone is

equally interested in enhancement of his or her intellectual performance. Apart from gender

differences, I suppose that personality exerts a strong effect on the felt need to enhance

cognitive performance. I would predict that narcissistic and ambitious personalities are

especially prone to the use of cognitive enhancers. Unfortunately, to my knowledge, there is

no study that has investigated the influence of personality on the preference of cognitive

enhancers.

Thus, there is no increasing or epidemic use of cognitive enhancers to date, and it is

unlikely that such a trend will develop given that seemingly only a minority of the population

is interested in regular use. Moreover, as stated above, a large number of potential users will

experience somatic side effects or negative effects on cognition that will result in

discontinuation of use. If the epidemiological account that I am providing is correct, then the

question is whether we are actually facing a problematic serious enough to warrant the large-

scale debate over neuroenhancement to which the discussed volume contributes.

In summary, the book Neuro-Enhancement provides a comprehensive compilation of

articles giving a good overview of the current debate over the ethics of cognitive

enhancement. Let me emphasize that I do not take issue with the philosophical quality of the

contributions. But, from my perspective as a neuroscientist, the debate which is so well

represented by the book is based on dubious assumptions. The participants of this discussion

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often claim that their speculative approach provides us with the unique opportunity to discuss

the ethical consequences of new technologies before they are fully developed. At least this

one time, ethics could be ahead of technology. However, do we really need a debate on a

technology that will probably never materialize?

Boris B. Quednow is assistant professor of Experimental and Clinical Pharmacopsychology

at the University Hospital of Psychiatry in Zurich. His main research interests are the

neurotoxicology of illegal drug use as well as the neurochemistry of cognition and disturbed

information processing in psychiatric diseases.

References Arnsten, A. F., & Li, B. M. (2005). Neurobiology of executive functions: catecholamine influences on prefrontal

cortical functions. Biol Psychiatry, 57(11), 1377-1384. Berridge, K. C. (2007). The debate over dopamine's role in reward: the case for incentive salience.

Psychopharmacology (Berl), 191(3), 391-431. Clatworthy, P. L., Lewis, S. J., Brichard, L., Hong, Y. T., Izquierdo, D., Clark, L., et al. (2009). Dopamine

release in dissociable striatal subregions predicts the different effects of oral methylphenidate on reversal learning and spatial working memory. J Neurosci, 29(15), 4690-4696.

DAK. (2009). Gesundheitsreport 2009: Analyse der Arbeitsunfähigkeitsdaten. Schwerpunktthema Doping am Arbeitsplatz. Hamburg: DAK Forschung.

de Jongh, R., Bolt, I., Schermer, M., & Olivier, B. (2008). Botox for the brain: enhancement of cognition, mood and pro-social behavior and blunting of unwanted memories. Neurosci Biobehav Rev, 32(4), 760-776.

Johnston, L. D., O'Malley, P. M., Bachman, J. G., & Schulenberg, J. E. (2005). Monitoring the Future national survey results on drug use, 1975-2004. Volume I and II: Secondary school students and College students and adults ages 19-45. Bethesda, MD: National Institute on Drug Abuse (NIH Publication Nos. 05-5727 and 05-5728).

Kahneman, D. (1973). Attention and effort. Englewood Cliffs, NJ: Prentice-Hall. Kapner, D. A. (2003). Recreational use of ritalin on college campuses. Newton, Massachusetts: The Higher

Education Center for Alcohol and Other Drug Prevention. Kapner, D. A. (2008). Recreational use of ritalin on college campuses. Newton, Massachusetts: The Higher

Education Center for Alcohol and Other Drug Prevention. Killgore, W. D., Rupp, T. L., Grugle, N. L., Reichardt, R. M., Lipizzi, E. L., & Balkin, T. J. (2008). Effects of

dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness. J Sleep Res, 17(3), 309-321.

Kumar, R. (2008). Approved and investigational uses of modafinil : an evidence-based review. Drugs, 68(13), 1803-1839.

Lanni, C., Lenzken, S. C., Pascale, A., Del Vecchio, I., Racchi, M., Pistoia, F., et al. (2008). Cognition enhancers between treating and doping the mind. Pharmacol Res, 57(3), 196-213.

Mattay, V. S., Callicott, J. H., Bertolino, A., Heaton, I., Frank, J. A., Coppola, R., et al. (2000). Effects of dextroamphetamine on cognitive performance and cortical activation. Neuroimage, 12(3), 268-275.

Mattay, V. S., Goldberg, T. E., Fera, F., Hariri, A. R., Tessitore, A., Egan, M. F., et al. (2003). Catechol O-methyltransferase val158-met genotype and individual variation in the brain response to amphetamine. Proc Natl Acad Sci U S A, 100(10), 6186-6191.

McCabe, S. E., Knight, J. R., Teter, C. J., & Wechsler, H. (2005). Non-medical use of prescription stimulants among US college students: prevalence and correlates from a national survey. Addiction, 100(1), 96-106.

Page 8: Ethics of neuroenhancement: a phantom debate. [Book review ...€¦ · enhancement, biological and technical brain implants, and genetic manipulations). I will not engage with the

7

Mehta, M. A., Owen, A. M., Sahakian, B. J., Mavaddat, N., Pickard, J. D., & Robbins, T. W. (2000). Methylphenidate enhances working memory by modulating discrete frontal and parietal lobe regions in the human brain. J Neurosci, 20(6), RC65.

Muller, U., Steffenhagen, N., Regenthal, R., & Bublak, P. (2004). Effects of modafinil on working memory processes in humans. Psychopharmacology (Berl), 177(1-2), 161-169.

Randall, D. C., Shneerson, J. M., & File, S. E. (2005). Cognitive effects of modafinil in student volunteers may depend on IQ. Pharmacol Biochem Behav, 82(1), 133-139.

Rasmussen, N. (2008). America's first amphetamine epidemic 1929-1971: a quantitative and qualitative retrospective with implications for the present. Am J Public Health, 98(6), 974-985.

Sussman, S., Pentz, M. A., Spruijt-Metz, D., & Miller, T. (2006). Misuse of "study drugs:" prevalence, consequences, and implications for policy. Subst Abuse Treat Prev Policy, 1, 15.

Teter, C. J., McCabe, S. E., Cranford, J. A., Boyd, C. J., & Guthrie, S. K. (2005). Prevalence and motives for illicit use of prescription stimulants in an undergraduate student sample. J Am Coll Health, 53(6), 253-262.

Wesensten, N. J., Belenky, G., Kautz, M. A., Thorne, D. R., Reichardt, R. M., & Balkin, T. J. (2002). Maintaining alertness and performance during sleep deprivation: modafinil versus caffeine. Psychopharmacology (Berl), 159(3), 238-247.