cognitive-enhancing substance use at german universities: frequency, reasons and gender differences

original article

262 Cognitive-enhancing substance use at German universities: frequency, reasons and gender differences 1 3

Neuro-Enhancement an deutschen Universitäten: Häufigkeit, Ursachen und Geschlechtsunterschiede

ZusammenfassungGrundlagen Medikamentöse Interventionen zur Steige-rung des Leistungs- und Funktionsniveaus wurden in der letzten Zeit vermehrt in der Öffentlichkeit diskutiert. Generalisierbare, objektive Daten, die Auskunft über die Höhe des tatsächlichen Konsums von leistungssteigern-den Mitteln geben, fehlen jedoch bislang. Ziel der vorlie-genden Studie ist es daher, die Häufigkeit des Gebrauchs von leistungssteigernden Mitteln unter deutschen Stu-denten zu untersuchen. Ferner werden Gründe für den Gebrauch und Geschlechtsunterschiede fokussiert.

Methodik Es wurde eine querschnittliche Online-Fragebogenstudie durchgeführt, in der 1.053 deutsche Studenten Auskunft über die Häufigkeit und Ursachen des Konsums von leistungssteigernden Mitteln geben sollten.

Ergebnisse 61 % der angeschriebenen Studenten be-antworteten den Fragebogen. Das Durchschnittsalter war 24 Jahre; 635 Studentinnen und 418 Studenten be-antworteten den Fragebogen 1–13 % der Studenten ga-

ben an mindestens einmal in ihrem Leben verschrei-bungspflichtige Stimulantien (z. B. Modafinil) und/oder illegale Drogen (z. B. Cannabis) zur Leistungssteigerung oder Entspannung genommen zu haben. Die Haupt-gründe für die Einnahme waren: Steigerung der Kon-zentration, Aufmerksamkeit und Entspannung. Es zeig-ten sich signifikante Geschlechtsunterschiede.

Schlussfolgerungen Die Studiendaten geben einen Einblick über die aktuelle Situation des Konsums von Substanzen zur Leistungssteigerung und dessen Motiva-tion. Institute der Gesundheitsversorgung sollten diese Situation weiterhin fokussieren und darauf aufbauend Aufklärungs- und Präventionsprogramme für Studenten an deutschen Universitäten entwickeln.

Schlüsselwörter: Drogen, Geschlechtsunterschiede, Neuro-Enhancement, Substanzmissbrauch

SummaryBackground The purpose of this study was to give an overview whether German students regularly use stimu-lants for enhancing their academic performance. Rea-sons associated with the use of these substances were explored. Moreover, gender differences were analyzed.

Methods A cross-sectional survey study was per-formed analyzing a random sample of 1,053 students of different fields of study in Germany. Students were asked to complete an anonymous self-administered web-based survey containing questions on cognitive performance-enhancing substance use. We used statis-tical analyses, e.g. non-parametric tests to evaluate the data of our questionnaire.

Results Among 1,053 students, 61 % responded to our questionnaire. The average age was M = 24.58; 635 par-ticipants were female and 418 were male students. Total 1–13 % of the participating students have taken prescrip-tion stimulants (e.g. modafinil) or illicit drugs (e.g. can-nabis) at least once in their lifetime. The most common reasons for taking stimulants were to support concentra-

Wien Med Wochenschr (2012) 162:262–271DOI 10.1007/s10354-012-0115-y

Cognitive-enhancing substance use at German universities: frequency, reasons and gender differencesStefanie Mache, Patrick Eickenhorst, Karin Vitzthum, Burghard F. Klapp, David A. Groneberg

S. Mache, PhD, MSc () · P. Eickenhorst, MD · K. Vitzthum, MSc, PhDInstitute of Occupational Medicine, Charité – Universitätsmedizin Berlin, Free University and Humboldt University, Thielallee 69–73, 14195 Berlin, Germanye-mail: [email protected]

S. Mache, PhD, MSc · Prof. B. F. Klapp, MD, PhDDepartment of Medicine/Psychosomatics, Charité – Universitätsmedizin Berlin, Free University and Humboldt University, Luisenstrasse 13a, 10117 Berlin, Germany

S. Mache, PhD, MSc · K. Vitzthum, MSc, PhD ·Prof. D. A. Groneberg, MD, PhDInstitute of Occupational Medicine, Social Medicine and Environmental Medicine, Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany

Received: 6 January 2012 / Accepted: 13 April 2012 / Published online: 16 June 2012© Springer-Verlag Wien 2012

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Cognitive-enhancing substance use at German universities: frequency, reasons and gender differences 2631 3

tion, to relax and to increase alertness. We found sig-nificant gender differences with regard to frequency and reason for using performance-enhancing substances.

Conclusions Our study results give an overview about the actual situation on frequency and reasons for taking performance-enhancing substances. Depart-ments of Public Health should address this issue in national health debates and discussions. Based on our study findings health education programmes should be developed.

Keywords: Cognitive enhancement, Drug use, Gender differences, Stimulants, Substance abuse

Introduction

During the past 2 years, ongoing strikes took place at Ger-many’s universities [1]. Thousands of students protested against the current study reforms in Germany. Students’ protest was related primarily to the unorganized imple-mentation of the Bachelor–Master’s degree programme at German universities. Changes in study programmes and shortcuts from 3 to 4 years of study duration periods have led students to complain about higher workloads and intensified timetables [2, 3].

It seems as if the majority of German students have problems in managing the present conditions in Bache-lor or Master’s degree programmes [4, 5]. Psychologi-cal information centres at universities have reported an increase of requests for psychotherapeutic counselling during the last years due to the introduction of these study reforms [6, 7].

In order to deal with the increased study demands, it is assumed that more and more German students are taking performance and cognitive-enhancing stimu-lants both for handling the pressure at university and to improve their academic performance [8–10].

Definition of cognitive enhancement and overview of substances

Cognitive enhancement is defined as the amplifica-tion or extension of core capacities of the mind through improvement or augmentation of internal or external information-processing systems [11]. According to this definition, a cognitively enhanced person is somebody who has benefited from an intervention that improves his/her cognitive performance without correcting a spe-cific pathology or dysfunction of that sub-system [11].

Research studies have illustrated the variety of cog-nitive enhancements which include not only medical interventions (enhancing drugs) but also psychological interventions (e.g. mental strategies) that support cogni-tion [12].

Performance and cognitive-enhancing substances can be grouped in prescription stimulants, illicit drugs and phytomedicine. Prescription stimulants include,

for example, amphetamines such as methylphenidate (brand names: Ritalin, Concerta, Metadate, or Methylin) or Adderall approved for treatment of attention-deficit hyperactivity disorder, postural orthostatic tachycardia syndrome, and narcolepsy [13].

Studies found out that methylphenidate increases accuracy in complex working memory tasks in normal individuals [14, 15]. Normally this stimulant is used to treat children affected by attention-deficit hyperacti-vity disorder [16]. Both types of amphetamines are not “over the counter” (OTC) medications in Germany [13]. Second, modafinil (brand names: Provigil, Alertec, Modavigil, Modalert) is another stimulant. Modafinil improves performance and executive functions and is usually used to treat narcolepsy and other sleep disor-ders [17, 18].

Illicit drugs playing a role in enhancing study perfor-mance are β-blockers, cannabis, cocaine or tranquilizer (e.g. benzodiazepines, herbal sedatives). Substances used most commonly by students to enhance their study performance are caffeine and energy drinks [9, 19, 20]. In addition, studies illustrated that cannabis and marijuana have been used to relax while studying [21].

Prevalence

The non-medical use of prescription stimulants (such as methylphenidate) in universities has recently drawn attention [22, 23]. Previous studies (mainly conducted in the United States) have shown high rates of students of different fields of study try to enhance their performance by taking stimulants [24–26].

Currently recognized as a serious public health issue among students in the United States [27–29], cognitive enhancement has been thoroughly investigated in both US high school and college students during the last years. The majority of studies focusing on cognitive enhance-ment among university or college students identified a lifetime prevalence ranging from 7 to 9 % [30–33].

The prevalence of cognitive performance behaviour outside the United States and Canada remains unclear.

Reasons for taking cognitive-enhancing substances

Studies performed mostly in North America detected that improving concentration was the most popular rea-son for taking performance-enhancing substances (e.g. stimulants or drugs) [34, 35], followed by increasing the focus for a specific task and memory capacity. In addi-tion, increasing creativity was mentioned as another determining reason [36, 37].

In addition, previous studies revealed that users taking caffeine pills, methylphenidate and modafinil (as non-medical stimulants) also report more likely the (ab)use of cigarettes, alcohol, cocaine and marijuana and other drugs than non-stimulant users [38, 39].

264 Cognitive-enhancing substance use at German universities: frequency, reasons and gender differences

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Aims of the study

As to our knowledge so far, only one study performed by Frankle et al. [40] has analyzed the usage, motives and gender effects for taking non-medical stimulants at German universities. Several studies have investigated the prevalence and reasons for taking performance-en-hancing substances in the United States and some other countries, but still there is no study that has examined factors influencing German students on whether to take such medications or refuse to do so.

The aim of this study was to give an overview on (1) how many German students have taken substances (e.g. stimulants) to enhance their performances at least once in their lifetime, (2) what kind of substances have been used (3) what reasons for using exist and (4) what factors that influence drug-taking behaviour can be found. In addition, questions on gender differences in the usage of substances for performance enhancement are of research interest.

Methods

Study design and participants

A cross-sectional study design was performed during October 2010–May 2011 in Berlin/Germany. We ana-lyzed students of different fields of study and different semesters/academic stages. Fields of study were medi-cine, economy, pharmacy, humanities and arts, natural sciences (e.g. chemistry; see Fig. 1). Semesters 1–14 were included in this study.

Students were invited to take part on a voluntarily basis via multi-address message. They were asked to fill out an anonymous online questionnaire about their per-sonal use of different stimulants.

Questionnaire

The content of the questionnaire was developed at the Department of Occupational Medicine and proved by

the department of Neurology at the Charité—Universita-etsmedizin Berlin for its completeness and correctness. In total, 138 items were included in the questionnaire.

Initially, the survey included questions regarding demographics (e.g. age, gender, field of study, number of study semester). Afterwards information on various fac-tors that may be related to the non-medical use of stimu-lants by university students was collected. The following items contained questions about the participants’ use of several substances to enhance their performance during studying. The first items of this part include: ampheta-mines, anti-depressants (SSRIs), anti-dementia drugs, and selective β-blockers, and/or the use of illegal drugs, to improve cognitive performance or mood. Other sub-stances with psychotropic properties were not covered. An overview of all included substances included in this study is shown in Table 1.

Additional items contained questions regarding the use of other non-prescription substances influencing performance or mood. We included items regarding the usage of caffeine tablets, cannabis, and various phyto-medicines (e.g. valerian, ginkgo biloba, St.Wort).

Fig. 1 Number of students per field of study 29

2219

16 14

0

5

10

15

20

25

30

35

Medicine Pharmacy Economy Natural Sciences Humanities and Arts

Fields of study

Perc

enta

ge (%

)

Table 1. List of substances students take to enhance their study performance

Substances Brand names

Medical

Modafinil Provigil

Methylphenidate Ritalin, Concerta

β-Blocker Beloc

Amphetamine Adderall, Desoxyn, Desoxyn Gradu-met, Dexedrine

Fluoxetine Prozac

Piracetam Nootropil, Qropi, Myocalm, Dinagen, Synaptine

Other non-medical

Cocaine

Phytomedicine (valerian, St. John’s wort, Gingko biloba)

Cannabis/marijuana

Caffeine pills

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Our questionnaire included generic and brand names in order to increase clarity for participating students (see Table 1).

The non-medical use of performance-enhancing substances was explored by a multiple choice list: First, we asked whether a student has ever taken any of these above-mentioned stimulants. In addition, frequency of use were asked: “If you have ever taken one or more of the following substances, how often do/did you take them, once per month, week, more times a week, more times a day”.

Moreover, reasons for taking stimulants were analy-zed. Reasons were: to improve academic performance, improve concentration, increase alertness and vigilance, relaxation, fear of disadvantages compared with drug users, manage the pressure to succeed, fun etc. (see Fig. 2). Respondents could select more than one reason (multiple-response questions).

Factors that influence drug-taking behaviour, such as being influenced by peers, advertisement, colleagues and university teachers etc. were also integrated in the questionnaire. In addition, personal variables (self-effi-cacy) were asked in the questionnaire. For that reason, the German version of the ‘Self-Efficacy, Optimism and Pessimism’ questionnaire (SWOP-K9) was also included [41]. This tests quality criteria has been approved [41].

The German version of ‘Self-Efficacy, Optimism and Pessimism’ questionnaire (SWOP-K9) was also included [41]. This tests quality criteria has been approved [41].

Reliability, validity and applicability of the question-naire were confirmed. Cronbach’s alpha coefficients for the items were higher than α = 0.70 and all inter-correla-tions were measured between r = 0.50 and r = 0.81.

Statistical analysis

We divided sub-groups by sex, age, field of study and uni-versity. Associations between student’s characteristics and the use of stimulants were tested using chi-square analyses. Since our data were not normally distributed, we used non-parametric tests to analyze for differences in frequency of use and reasons by sex, age, number of semesters and field of study (e.g. chi-square analyses). An α level of 0.05 was used for each statistical test. Sta-tistical analyses were performed using SPSS for Windows Version 19.0.

Statement:All included participants gave their informed consent

to be included in the study. Moreover, students partici-pate on a voluntary basis. The ethical aspects were in full agreement with the Helsinki declaration. This study was approved by the Research Ethics Board at the Humboldt-University of Berlin.

Results

A total of 1,053 surveys were collected (response rate = 61 %). The distribution between male and female students was 635 women/418 men. The mean age of stu-dents in the sample was 24.58 (SD = 5.47 years), the mean number of study semesters was 6 (SD = 4).

Frequency

Figure 3 illustrates characteristics for the overall sample, broken down by drug-use status: non-medical use of pre-scription stimulants or drug use other than non-medical

Fig. 2 Reasons for taking cognitive-enhancing substances

5753

46

3934

26

1912

9 96

10

10

20

30

40

50

60

70

Impro

ve co

ncen

tratio

n

Increa

se ale

rtness

/vigil

ance

Impro

ve ac

adem

ic pe

rform

ance

Relaxa

tion i

n gen

eral

Fear of

disad

vanta

ges co

mpared

with

drug

users

Manag

e the p

ressur

e to s

uceed

Increa

se mem

ory fu

nctio

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Stress

reduc

tion

Relaxa

tion d

uring

exam

s

Friend

s tak

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Curiosi

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Reasons

Perc

enta

ge (%

)


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use of prescription stimulants (including, for example, marijuana, cocaine, methylphenidate, amphetamines).

As shown in Fig. 3, 2 % of stimulant users reported taking methylphenidate products, whereas 0.6 % have used modafinil at least once in their lifetime.

Phytomedicines (e.g. valeria as a mild sedative) were clearly the most prevalent medications used by students

(22 %), at rates ten times higher than that of modafinil, methylphenidate products, or cannabis. More than 15 % of the students reported having smoked cannabis/mari-juana at least once in their lifetime. Figure 4 illustrates how often students, reporting on frequency of usage, take specific stimulants during a month, week or day.

Fig. 3 Distribution of sub-stance use among German students

22

15

10

2 .3 2 .2 2 1 .1 1 1 0 .10

5

10

15

20

25

Phytom

edicin

e

Cannab

is/mari

juana

Caffein

e pills

Cocaine

Methylp

henid

ate

Ampheta

mine

β-Bloc

ker

Fluoxet

ine

Modafi

nil

Piracet

am

Substances

Perc

enta

ge (%

)

Fig. 4 a Non-medical use of prescription stimulants among German students. b Non-medical use of other stimulants among German students

1

0.4

1

0.9

0.5

0.1

0.4

0.2 0.2

0.1

0.2

0.1 0.1

0.3

0.9

0.3

0.1 0.1

0

0.2

0.4

0.6

0.8

1

1.2

Methylphenidate Modafinil ß-Blocker Amphetamine Fluoxetine Piracetam

Substances

Perc

enta

ge (%

)

less than one per month once a month once a week once a day several times a day

15

8,3

2

5.8

3 2.2

0.31.61.8 1.6 1.41.4

0.3 0.50.7 0.3 0.40

2

4

6

8

10

12

14

16

Phytomedicine Cannabis/Marijuana Cocaine Caffeine pillsSubstances

Perc

enta

ge (%

)

less than one per month once a month once a week once a day several times a day

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No significant differences could be found regarding age or number of semesters (p > 0.05).

No significant differences could be found in perfor-mance-enhancing drug-taking behaviour comparing medical students with other student groups of different fields of study (p > 0.05).

Reasons

As expected, reasons for taking performance-enhancing stimulants were multiple (see Fig. 2). Total 46 % of users indicated that they took these drugs to improve their academic performance. As illustrated in Fig. 2, other commonly reported reason for the use of cognitive-en-hancing stimulants were to improve concentration (57 % of respondents), increase alertness/vigilance (53 %) and to increase memorizing functions (19 %). Other reasons with a percentage of 26 % were “stand the pressure to succeed”, “to cope with stress” (9 %), curiosity (1 %) and “because others are doing it” (6 % of the students men-tioned this factor). “Being afraid of having disadvantages to those who are taking cognitive-enhancing drugs” can put a student further at risk for cognitive-enhancing drug-taking behaviour (30 %).

Total 19 % of the misusers responded taking illicit drugs such as ecstasy and marijuana for non-academic reasons (e.g. having fun).

We found no significant differences in reasons for taking stimulants comparing medical students with other student groups of different fields of study (p > 0.05).

Gender differences

There was no significant difference between male and female students with regard to type and frequency of taking prescription stimulants such as methylphenidate (p > 0.5). In contrast, male students have taken illicit drugs such as cannabis and cocaine significantly more often than their female colleagues (p < 0.05).

The reason “to experiment” and “was curious” was reported significantly more often by men than by women (p < 0.05). No significant difference between male and female students could be found for the reason “to help concentrate” (p > 0.05).

Female students have used phytomedicine signifi-cantly more often than male students (p < 0.05). With regard to other performance-enhancing stimulants (e.g. methylphenidate) no significant gender difference could be found (p > 0.05).

Factors that influence cognitive-enhancing drug-taking behaviour

Our results illustrated peers (such as student colleagues, friends and acquaintances) have the greatest influence (38 %). Among participants who admitted having ever

used any of the above substances, 79.4 % were introdu-ced by a friend, acquaintance or a classmate while 21.6 % were introduced by a relative.

No significant association could be found between the use of prescribed, illicit stimulants and self-reported scores on self-efficacy (p > 0.05).

Discussion

This cross-sectional study was performed to examine the relevance of performance-enhancing stimulants taken by German students. In addition, reasons playing a role in students’ decision taking such pills and gender diffe-rences were analyzed.

Frequency

The stimulants most often taken by German students were herbal sedatives (such as valerian or cannabis). Several international research studies affirm our results; lifetime prevalence rates vary between 13–48 % for can-nabis use among college students in the United States, Canada and Ireland [42–44]. A lifetime prevalence of 19–57 % for phytomedicine (such as valerian and other herbal sedatives) was found in other previous analyses [45–47].

Our results indicated that up to 2 % of all surveyed stu-dents use prescription stimulants to enhance cognitive ability.

These results are not in accordance with previous investigations performed in the United States. Teter et al. [24, 32] found a lifetime prevalence of 8.1–8.3 % and past year prevalence of 5.4–5.9 %. In comparison to other study results presented by McGabe et al. [48], the amount of students taking stimulants to increase their academic performance was lower in our study. This result may indi-cate that a misuse of cognitive-enhancing drugs is not an increasing trend among university students in Germany right now. This suggestion is in accordance with study results performed by Franke et al. [40]. They found life-time prevalence for the use of prescription stimulants (methylphenidate etc.) of 0.78 % among German stu-dents. In addition, they reported a lifetime prevalence of illicit use of stimulants (ecstasy, cocaine) of 2.93 % among German students [40].

According to these findings, our results have illustra-ted the consumption of drugs is significantly lower com-pared with studies from the United States [24]. Reasons can be seen in an easier access to these drugs in the Uni-ted States. Secondly, the motivation of enhancing perfor-mance by taking stimulants is higher [34, 49]. Moreover, pharmaceutical advertisement is not as restricted in the United States as in Germany. This might also influence the awareness of stimulant use for cognitive-enhancing motives.

Our results confirm previous research findings that the majority of the participating students take multiple


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drugs at the same time (i.e. poly-drug use) [24, 50]. Poly-drug use causes significant health and safety risks [51]. Therefore, interventions such as educational adverti-sement or other health-related awareness campaigns should inform German students of possible side effects (medical problems).

Gender differences

In the present study, we found that female students reported a higher consumption of herbal sedatives such as valerian. This result may implicate that female students have a particular vulnerability to relaxing substances due to examination anxiety. This suggestion is consistent with previous research. Female students report more mental health (e.g. examination fear) and sleep problems during their studying time [52, 53] than their male colleagues, which may lead to their higher consumption of relaxing substances. In general, females ask more often for rela-xing and anxiolytic medications than males [54, 55].

No significant gender differences across the prescri-bed medications such as methylphenidate were obser-ved. This result is comparable with other study results [56, 57].

In contrast, other studies have shown that males are more likely to use prescribed medications whereas fema-les are at a higher risk to become addicted [58, 59].

However there was a significant difference concerning the use of illicit drugs. Male students reported a higher use of cannabis and marijuana than did female students. This result is in line with previous study results [60]. This result leads to the suggestion that female students try to relax by using phytomedicine or other non-medical rela-xing techniques (e.g. yoga) whereas male students do so by taking illicit drugs (e.g. cannabis). Further research should investigate such association.

Reasons

The desire for cognitive enhancement was reported as the main reason for the misuse of prescription stimu-lants. This result may indicate that the majority of those students believe that their academic performance incre-ases from those stimulants.

Our results may be interpreted and connected to previ-ous research studies which have illustrated that the pres-sure on German students has been increased over the last years [61, 62]. Students report they have to perform more tasks in less time and examinations are more dif-ficult than in previous years [7]. They are all demanding better educational conditions at their universities such as more teaching staff and better technical equipment.

Current study results verify the above-mentioned complaints cause an increase of psychosocial strain among German students [3].

Indicators for this development are a steady increase of request for psychosocial counselling at German uni-

versity information centres and an increase of suicidal rates after failing examinations.

German researchers are increasingly warning about the link between studying these days and stress. A study by Jurkat et al. [63] illustrated every fifth German student reported feeling depressed, and every fourth student complained about suffering from excessive neck and back pain and/or having difficulties in concentrating.

Accordingly, our results may indicate some students take drugs to manage the current vast study demands.

In order to prevent students from feeling over-worked and suffering from stress-related psychological illnesses, public health funds should develop special preventative health programmes at universities. Compulsory courses on stress-free studying and how to handle and cope with study demands (e.g. time-management, how to relax) without turning to alcohol, drugs or medication should be implemented at schools and universities.

Influences on drug-taking behaviour

Our study results implicate German students are particu-larly vulnerable because of the strong influence of peer pressure. Comparable studies illustrated friends and acquaintances have the greatest influence [64].

Similar to the students of the United States or Canada, German university students have inaccurate perceptions of peer-substance use [43]. In accordance to previous studies, cognitive-enhancing peers can influence even those without risk factors (e.g. home environment) to try prescription stimulants for the first time. Academic fai-lure or poor social skills can put a student further at risk for cognitive enhancement [65–67].

In addition, our study results have shown there was no significant difference in cognitive-enhancing behaviour depending on how one’s own self-efficacy is perceived. Previous research has shown self-efficacy is often per-ceived as a protective factor against substance abuse [68, 69]. It seems as if cognitive-enhancing behaviour does not depend on personal skills such as self-efficacy or coping skills. Additional research is needed to prove this consumption.

Associations between other personal factors (e.g. neuroticism) and the use of cognitive-enhancing stimu-lants among students would also be of further research interest.

Limitations

There are some limitations that need to be acknow-ledged and addressed regarding the present study. First, there may have been some bias in the survey-collection method. The sample may include only those students who were interested in cognitive-performance enhancement.

Non-responder especially those who take prescription stimulants may have introduced an underestimation of use in our study. However, characteristics of the study

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sample are comparable with those of the overall student population in Germany. Therefore, this limitation seems to be of less influence.

In addition, due to the cross-sectional design of the study, we are unable to make causal statements, for exa-mple, whether taking cannabis is a catalyzer to the use of prescription stimulants such as modafinil.

A qualitative study may prove instrumental in further understanding prescription drug-use behaviours among students in Germany.

In addition, further investigations need to be done to determine how often physicians or pharmacists are involved in selling performance-enhancing medication.

Although our study sample has an adequate response rate, the results cannot be generalized to all German stu-dents. Further quantitative research studies, particularly investigating a national-wide population are strongly encouraged. In addition, long-term effects on students’ academic performance after using cognitive-enhancing stimulants are of interest. More studies should focus on possible side effects of cognitive enhancement in heal-thy students (e.g. medical problems, addiction to these stimulants).

Conclusion

In conclusion, despite distinct cultural and regulatory restrictions, our study corroborated on several findings from the United States and Canada, with regards to the most commonly abused medications, influencing factors and increased likelihood of the use of other substances (e.g. alcohol, marijuana).

Despite the mentioned limitations, our study makes an important contribution to Germany’s health (policy) reporting by giving an overview on the relevance of drug-taking behaviour.

Despite the current low prevalence for cognitive-enhancing (stimulant-taking) behaviour, our results may have influence on health-policy decisions and implica-tions. Prevention and intervention efforts should inform German students about potential health risks of using prescription drugs without medical supervision.

Based on our results, future health educational inter-ventions especially for younger age groups could be developed. In addition, comparisons focusing on the development of drug-taking behaviour at different Ger-man universities should be performed in future studies. Our study results may act as a baseline for further data sets.

If indeed males and females differ in their vulnera-bility to (ab)use, prevention efforts may be improved by developing interventions that specifically target male or female students.

AcknowledgementsWe thank all students for participating in our study. In addition, we also thank Mrs. Gabriele Volante for lang-uage editing.

Conflict of interestAll authors declare that they have no conflict of interest.

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cognitive-enhancing substance use at german universities: frequency, reasons and gender differences

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