The Role of Socioeconomic Conditions and Psychological Factors in the Willingness to Volunteer for Phase I Studies

Pharm Med 2008; 22 (6): 367-374ORIGINAL RESEARCH ARTICLE 1178-2595/08/0006-0367/$48.00/0

© 2008 Adis Data Information BV. All rights reserved.

The Role of Socioeconomic Conditions andPsychological Factors in the Willingness toVolunteer for Phase I StudiesLuis Almeida,1,2 Amilcar Falcao,3 Rui Coelho,4 Antonio Albino-Teixeira2,5 and Patricio Soares-da-Silva1,2

1 Department of Research and Development, BIAL (Portela & Co., SA), S. Mamede do Coronado, Portugal2 Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal3 4Health Consulting Ltd, Cantanhede, Portugal4 Service of Psychiatry and Mental Health, Faculty of Medicine, University of Porto, Porto, Portugal5 Institute for Molecular and Cell Biology, University of Porto, Porto, Portugal

Aim: To assess the role of socioeconomic conditions and psychological factors in the decision of healthyAbstractsubjects to participate in a phase I study.Methods: Subjects (n = 117) were given information about a phase I study and asked to participate. Subjectswere assessed regarding their demographic and socioeconomic characteristics, and evaluated using the Curiosityand Exploration Inventory (CEI-T), Self-Efficacy Scale (SES), State-Trait Anxiety Inventory (STAI), Fear ofNegative Evaluation (FNE) and Social Avoidance and Distress (SAD) scales, and the Beck DepressionInventory-II (BDI-II).Results: In a univariate analysis, a significant positive correlation (Spearman’s rho) was found betweenwillingness to participate in the proposed phase I study and CEI-T exploratory tendencies (R = 0.338; p < 0.001)and total scores (R = 0.276; p < 0.01), SES total scores (R = 0.299; p < 0.01) and SES subscales for initiative andpersistence (R = 0.290; p < 0.01), planning/goal setting (R = 0.189; p < 0.05) and social self-efficacy (R = 0.294;p < 0.01). A significant negative correlation was found between willingness to participate and STAI anxiety-state(R = –0.229; p < 0.05), STAI anxiety-trait (R = –0.260; p < 0.01) and SAD (R = –0.204; p < 0.05) scores. In alogistic regression model, CEI-T exploratory tendencies, SES initiative and persistence, and STAI anxiety-traitwere the only unique significant predictors of willingness to participate in the proposed phase I study (allp < 0.05). Yet, although subjects who refused and those who were willing to participate were significantlydifferent in these personality traits, they showed no marked differences in their demographic or socioeconomiccharacteristics, including monthly income. A significant positive correlation was found between CEI-T explora-tion scores and willingness to participate without financial reward (R = 0.269; p < 0.05). There was an inversecorrelation between perceived risk of participation and willingness to participate (R = –0.236; p < 0.05).Conclusion: Subjects higher in initiative, persistence and exploratory tendencies, and lower in anxiety-traitswere more willing to accept participation in a phase I study. These personality traits had a more decisiveinfluence on the subjects’ willingness to volunteer for a phase I study than socioeconomic conditions, such asmonthly income.

Phase I studies in healthy subjects are fundamental to the and so will have no direct health benefit from participation;development of new drugs. Every year, thousands of healthy second, participation usually requires confinement with previouslysubjects participate in phase I studies, but little is known about unknown people for several days in research wards with minimalwho they are and why they volunteer.[1] Several reasons can be privacy and the performance of unaccustomed procedures, somefound that argue against participation: first, subjects are healthy of which are relatively invasive and painful, such as venous

368 Almeida et al.

catheterization; third, there is a risk of adverse events, which consent information for a crossover, drug-drug interaction, phase Ioccasionally can be serious or even life-threatening.[2] Therefore, study to be conducted as part of the clinical development of a newone may ask why a healthy subject volunteers for participation. drug for the treatment of Parkinson’s disease, and asked to com-

plete a questionnaire that is summarized in table I.Previous research has shown that financial reward is the mainmotivation for most subjects who volunteer for phase I studies.[3-7] The informed consent information for this phase I study hadHowever, there are economically disadvantaged people who com- been approved by an Independent Ethics Committee (IEC) andpletely reject the idea of participation in a phase I study, showing included the description of the main pharmacological properties ofthat financial reward is not sufficient to get consent in some the drug, time of residence at the clinical research facilities, studysubjects. On the other hand, there are subjects who agree to pharmacokinetic and safety procedures to be performed during theparticipate in phase I studies even in the absence of financial study, potential adverse effects, restrictions (e.g. prohibition ofreward.[3] Therefore, the financial reward does not fully explain drinking alcoholic beverages or xanthine-containing beverages,why only a subgroup of subjects consent to take part in phase I smoking) and precautions (e.g. need for sexual abstinence orstudies.[8] The decision of whether or not to participate is certainly barrier contraception measures during the study), and the financialrather complex and influenced by the subject’s values (e.g. altru- compensation approved by the IEC for that specific study. Inism), psychological states and personality traits. accordance with the existing standard operating procedures, finan-

The risk, even if minimal, of adverse effects and painful proce- cial compensation approved for that phase I study had beendures associated with phase I studies may be found to be partic- calculated to take into account the number of hours the participantularly threatening for subjects with high anxiety. Similarly, people would spend participating in the phase I study and their travelwith social anxiety may find the close interaction with clinical costs.staff and other study participants, as well as the potential need for Subjects were also asked to fill in questionnaires regarding theirresiding for several days in the research facilities with a relatively demographic and socioeconomic characteristics, curiosity and ex-low level of privacy, to be too distressing to consider participating ploratory tendencies, perceived self-efficacy, anxiety, depressionin a phase I study. On the other hand, people with a high level of and social anxiety. In order to preserve the confidentiality ofcuriosity and perceived self-efficacy prefer novel, complex and subjects’ personal data, an anonymity method was implemented.challenging experiences, as is the case with phase I studies. Curiosity, interest, novelty-seeking and openness to experienceTherefore, it can be hypothesized that psychological factors such represent one’s intrinsic desire for experience and knowledge.[9]

as anxiety, depression, social anxiety, curiosity and perceived self- Curiosity can be defined as a positive emotional-motivationalefficacy may have an effect on the subject’s willingness to system associated with the recognition, pursuit and self-regulationvolunteer. However, little is known about such psychological of novel and challenging opportunities, reflecting intrinsic valuesfactors as a source of self-selection bias for phase I clinical trials. and interests.[10] The trait curiosity refers to predisposition inTo further clarify this issue, we report the findings of a study in curiosity behaviours.[11] A person high in trait curiosity preferswhich we have assessed the role of socioeconomic conditions and novelty, complexity, uncertainty and conflict and is more likely topsychological factors in the self-selection of healthy subjects for be involved in novel and challenging experiences.[11,12] Curiositytheir first-time participation in a phase I study. was assessed by the Curiosity and Exploration Inventory – Trait

(CEI-T).[10] CEI-T is a 7-item scale that assesses two dimensionsof curiosity: exploration (general strivings to seek out novelty,Material and Methodschallenge, uncertainty and intriguing experiences), and absorptionor flow (the propensity to be deeply absorbed in the target of one’sAs described elsewhere,[3] ‘word-of-mouth’ has been the re-attention).cruitment method for approximately 95% of participants in phase I

studies conducted at BIAL’s Human Pharmacology Unit in S. Self-efficacy is defined as belief in one’s capabilities to mobil-Mamede do Coronado, Portugal. Participants in the current study ize the motivation, cognitive resources, and courses of actionwere a group of healthy subjects who were selected using the usual needed to meet given situational demands.[13] Self-efficacy refersrecruitment procedure for phase I studies.[3] to one’s impression of what one is capable of doing.[14] People

An estimated 200 subjects were personally contacted in the with high self-efficacy choose to perform more challenging tasks,places (universities and work places) from which participants invest more effort and persist longer than those who are low inusually come and asked if they would participate in a survey self-efficacy; people with low self-efficacy, doubting their capa-involving the completion of some questionnaires. The 120 sub- bilities, avoid or abort difficult tasks and often view them asjects who agreed to cooperate were provided with the informed personal threats (as opposed to challenges).[15] Self-efficacy was

© 2008 Adis Data Information BV. All rights reserved. Pharm Med 2008; 22 (6)

Decision Factors when Volunteering for Phase I Studies 369

Table I. Results of the questionnaire regarding phase I study participationa

Answer Subjects [no. (%)]

Question 1: Ever participated in any clinical trial? (n = 120)

Yesb 3 (2.5)

No 117 (97.5)

Question 2: Interested in participating in the current phase I study? (n = 117)

No 59 (50.4)

Maybe 28 (23.9)

Yes 23 (19.7)

No answer 7 (6.0)

Question 2.1: In case you are not interested in participation, why not? (n = 57)

Fear of complications 34 (59.6)

Financial reward not attractive enough 9 (15.8)

Busy personal life 8 (14.0)

Other 6 (10.5)

Question 2.2: In case you answer “maybe”, what are your conditions for participation? (n = 28)

Compatibility of study timeliness with my personal life 25 (89.3)

If a friend also would participate 3 (10.7)

Question 2.3: In case you have answered you could be willing to participate, why would you participate? (n = 50)c

Curiosity 15 (30.0)

Progress of medicine/science 24 (48.0)

Financial reward 29 (58.0)

Otherd 1 (2.0)

Question 3: In case you are willing to participate, would you accept to participate in a clinical trial if no financial reward? (n = 50)

Yes 7 (14.0)

No 24 (48.0)

Maybe 19 (38.0)

Question 4: Do you consider it ethical to financially reward for participation? (n = 108)

Yes 95 (88.0)

No 13 (12.0)

Question 4.1: If you consider it ethical to pay, what should be compensated? (n = 95)c

Health risk 56 (58.9)

Time spent 67 (70.5)

Discomfort 37 (38.9)

Residency 35 (36.8)

Away from home 35 (36.8)

Other 6 (6.3)

Question 5: How do you rate the risk of participation in a phase I study? (n = 107)

No opinion 35 (32.7)

Risk is minimal 42 (39.3)

Risk is moderate 20 (18.7)

Continued next page


370 Almeida et al.

Table I. Contd

Answer Subjects [no. (%)]

Risk is high 10 (9.3)

a Not all subjects answered all questions.

b Subjects who answered ‘yes’ were excluded from the analysis.

c More than one answer was allowed.

d The ‘Other’ answer was: possibility of having a careful health checkup.

assessed through the Self-Efficacy Scale (SES).[16] It focuses on interaction situations.[25] High SAD scores reflect a greater likeli-hood of avoiding potentially stressful social interactions.[27]willingness to initiate behaviour, willingness to expend effort in

completing behaviour and persistence in the face of adversity. It is The first set of analyses consisted of Spearman’s rho correla-composed of three subscales (initiative/persistence, planning/goal tions between the scales scores (independent variables) and thesetting and social self-efficacy), and has been shown to be a valid type of answers (dependent variables) to questions asked on thepredictor of academic and professional behaviour,[16,17] self-es- questionnaire summarized in table I, and between scales scores

(independent variables) and willingness to volunteer for phase Iteem[18] and general adjustment.[19,20] In our study, we used aparticipation (dependent variable). In addition to these univariate15-item Portuguese validated adaptation[21] of the original scale.[16]

analyses, the independent contribution of the SES, CEI-T, STAI,The subjects’ anxiety was assessed by the State-Trait AnxietyBDI-II, SAD and FNE scores on the prediction of a “Yes” to theInventory (STAI).[22] The STAI consists of two separate scales:invitation to phase I participation was tested by using multivariatestate anxiety (STAI-S), which refers to a transitory emotional statelogistic regression. Statistical analyses were performed with thecharacterized by subjective feelings of tension that may vary inStatistical Package for Social Sciences software (SPSS® 11.5;intensity over time, and trait anxiety (STAI-T), which refers to aSPSS Inc., Chicago, IL, USA).relatively stable and long-standing disposition to respond to stress

The study reported here was approved by an IEC (Comissao dewith anxiety and a tendency to perceive a wider range of situationsEtica Independente da UFH, Porto, Portugal). Participants in theas threatening.[22] Scores vary from a minimum of 20 to a maxi-current study were not paid for their participation. Those subjectsmum of 80 and they have a direct interpretation: high scores meanwho agreed to participate in the proposed phase I study and whomore anxiety and low scores indicate less anxiety.actually enrolled, received financial compensation approved by

The presence of depressive symptoms was assessed using a the IEC.Portuguese adaptation[23] of the Beck Depression Inventory-II(BDI-II).[22] BDI-II is a 21-item self-report scale for assessing

Resultscognitive, affective and somatic symptoms of depression duringthe previous 2 weeks. Scores can vary from a minimum of 0 to a Table I presents the results of the questionnaire regardingmaximum of 63. Higher total scores indicate more severe depres- participation in a phase I study (n = 120). When asked whether orsive symptoms. not the subject had already participated in a clinical trial (question

Social anxiety is defined as the fear and avoidance of social 1), 3 (3%) subjects declared they had previously participated in ainteractions in which a person might be exposed to negative phase I study and were removed from the analysis. Among the 117evaluation by others.[24] Research suggests that social anxiety phase I trial-naive subjects, 7 (6%) subjects gave no answer as toexists on a continuum, from absence of social fear, through shy- whether they were interested in participating in the study. Amongness and mild social anxiety, to social anxiety disorder.[24] Two the remaining 110 subjects, 59 subjects declared they were unwill-scales were used to measure the behavioural and cognitive com- ing to participate (answer “No” to question 2 of table I), inponents of social anxiety: Fear of Negative Evaluation (FNE) and approximately 60% of cases this was because of the fear ofSocial Avoidance and Distress (SAD).[25] The FNE consists of 30 complications and in 16% because the financial reward was nottrue-false questions and assesses the expectation and fear of nega- considered attractive. In total, 51 subjects declared that they couldtive evaluation from others in a social climate. High FNE scores be willing to participate (answer “Yes” or “Maybe” to question 2reflect a greater fear of negative evaluation from others.[26] The of table I); their main motivations were the promised financialSAD consists of 28 true-false questions and assesses social anxiety reward (58%), to contribute to the progress of medicine (48%) andthat stems from participation in social interactions, and fear- curiosity (30%). Most subjects (88%) considered it ethical to pay amotivated avoidance and subjective distress in a variety of social financial reward for phase I study participation; the most common



Table II. Main demographic and socioeconomic characteristics of the study population according to the willingness to participate in a phase I study

Parameter Variable Subjects

“no” (n = 59) “maybe” (n = 28) “yes” (n = 23)

Gender (%) Male 42.4 50.0 47.8

Female 57.6 50.0 52.2

Age (y) Mean ± SD 26.6 ± 7.3 25.2 ± 5.5 27.5 ± 7.8

Median 24 25 27

Range 18–45 18–40 18–45

Ethnic origin (%) Caucasian 98.3 96.4 95.7

Other 1.7 3.6 4.3

Occupation (%) Student 55.9 57.1 56.5

Employed 32.2 39.3 34.8

Unemployed 11.9 3.6 8.7

Monthly net income in relation to (%) <25 28.6 31.8 29.4

the mean national net salary in the (%) 25–50 24.5 40.9 29.4

industry and services sectora (%) 51–100 28.6 13.6 35.3

101–150 12.2 13.6 5.9

>150 4.1 0.0 0.0

Martial status (%) Single 67.2 81.5 65.2

Married/cohabiting 27.6 14.8 30.4

Divorced 5.2 3.7 4.3

School degree completedb (%) 4 years 6.8 0.0 4.3

6 years 3.4 3.6 4.3

9 years 5.1 7.1 13.0

12 years 55.9 57.1 65.2

Bachelor degree 6.8 3.6 8.7

University graduation 20.3 25.0 4.3

Masters degree 1.7 3.6 0.0

Smoking (%) ≥1 cigarette/day 27.1 22.2 21.7

Coffee drinking (%) ≥1 cup/day 66.1 51.9 62.5

Exercising/sports (%) ≥1 session/week 47.5 81.5 60.9

Alcohol consumption (%) ≥1 occasion/week 44.1 51.9 56.5

a Approximately €1000/month, net in 2007.

b ‘Bachelor’ degree represents a university course of 2–3 years; ‘University graduation’ represents a full university course, taking between 4–6 years(the number of years depends on the type of study undertaken: e.g. literature = 4 years; engineering = 5 years; medicine = 6 years).

reasons for financial reward were to compensate for the time spent pate (R = –0.236; p < 0.05) and between perceived risk of partici-while participating in a study (71%) and/or for the health risk that pation and willingness to participate without financial reward (R =participation represents (59%). Approximately 33% of subjects –0.349; p < 0.05). Perceived risk was higher in subjects with ahad no opinion about the level of risk of participating in a phase I lower SES total (R = –0.194; p < 0.05) and planning/goal settingstudy; approximately 39% of subjects considered the risk to be (R = –0.205; p < 0.05) scores. Subjects who considered it unethicalminimal. to be paid showed lower SES planning/goal setting scores (R =

–0.203; p < 0.05).A significant positive correlation was found between CEI-Texploration scores and willingness to participate without financial Table II presents the main demographic and socioeconomicreward (R = 0.269; p < 0.05). An inverse correlation was found characteristics by subgroups created according to the willingnessbetween perceived risk of participation and willingness to partici- to volunteer for participation in the proposed phase I study. When


372 Almeida et al.

Table III. Median and interquartile range (IQR) of scales scores and Spearman’s correlation between scale scores and willingness to volunteer to a phase Istudy

Scale Median (IQR) Spearman’s rho p-Value

“no” (n = 59) “maybe” (n = 28) “yes” (n = 23)

SES total 78 (16) 85.5 (14) 88 (15) 0.299 <0.01

Initiative and persistence 31 (8) 35 (7) 35 (6) 0.290 <0.01

Planning/goal setting 27 (6) 30 (6) 29 (7) 0.189 <0.05

Social self-efficacy 20 (4) 22 (5) 22 (6) 0.294 <0.01

CEI-T total 36 (7) 39 (8) 41 (7) 0.276 <0.01

Exploration 20 (4) 21.5 (4) 24 (3) 0.338 <0.001

Absorption 16 (4) 16 (4) 18 (5) NS NS

STAI anxiety-state 40 (15) 34 (16) 32 (11) –0.229 <0.05

STAI anxiety-trait 42 (12) 37 (12) 35 (9) –0.260 <0.01

BDI-II 6 (9) 4 (10) 5 (15) NS NS

SAD 8.5 (7) 6.5 (11) 4 (6) –0.204 <0.05

FNE 17 (9) 13.5 (8) 16 (7) NS NS

BDI-II = Beck depression inventory-II; CEI-T = curiosity and exploration inventory – trait; FNE = fear of negative evaluation; NS = not significant; SAD =social avoidance and distress; SES = self-efficacy scale; STAI = state-trait anxiety scale.

the “No” and “Yes” subgroups were compared, no relevant differ- • a significant positive correlation between subjects’ willingnessto participate in the phase I study and CEI-T exploratoryences were found for gender, age, ethnic origin and martial status.tendencies and total scores, as well as SES total scores and SESAmong those subjects with a monthly income >100% of thesubscales;

reference earning (mean net salary in the national industry and• a significant negative correlation between subjects’ willingnessservices sector), the percentage of subjects in the “Yes” subgroup

to participate and state- and trait-anxiety measured by STAIwas markedly lower than in the “No” subgroup (6% vs 16%).

and social anxiety measured by SAD.However, the percentage of subjects with monthly income lower

Table IV presents the results of the logistic regression modelthan 25% of the reference earning was similar in both the “No” and composed to explore the unique contributions of each scale com-“Yes” subgroups (29%). ponent to the prediction of a “Yes” to the invitation to participate

The results of the univariate analysis (table III) showed: in the proposed phase I study, using the scales scores as covariates.

Table IV. Summary of logistic regression analysis of Self-Efficacy Scale (SES), Curiosity and Exploration Inventory – Trait (CEI-T), State-Trait AnxietyScale (STAI), Beck Depression Inventory-II (BDI-II), Social Avoidance and Distress (SAD) and Fear of Negative Evaluation (FNE) scores as predictors ofwillingness to participate in a phase I clinical trial

Scales β SE Exp(B) 95% CI for Exp(B) p-Value

SES initiative and persistence 0.152 0.072 1.164 1.010, 1.341 <0.05

SES planning/goal setting –0.127 0.084 0.881 0.746, 1.039 NS

SES social self-efficacy 0.202 0.112 1.223 0.981, 1.525 NS

CEI-T exploration 0.262 0.124 1.299 1.019, 1.656 <0.05

CEI-T absorption –0.119 0.125 0.888 0.694, 1.135 NS

STAI anxiety-state –0.006 0.046 0.994 0.908, 1.088 NS

STAI anxiety-trait –0.071 0.028 0.930 0.875, 0.998 <0.05

BDI-II 0.054 0.052 1.055 0.952, 1.170 NS

SAD –0.035 0.057 0.966 0.864, 1.080 NS

FNE 0.126 0.070 1.135 0.990, 1.301 NS

Constant –10.640 3.759 0.000

β = regression coefficient; CI = confidence interval; Exp(B) = odds ratios; NS = not statistically significant; SE = standard error of the mean.



Only SES initiative and persistence (p < 0.05), CEI-T exploration commit to actually participate in a study without financial reward,(p < 0.05) and STAI anxiety-trait (p < 0.05) were found to be some of them would decline.statistically significant predictors of willingness to volunteer for As mentioned before, ‘word-of-mouth’ is the the most commonparticipation. way of finding new volunteers to participate in studies conducted

in our clinical pharmacology unit. No mass advertising is allowedand priority has been given to university students living in theDiscussionmetropolitan area where the research facilities are located. In thecurrent study, the recruitment strategy normally used for finding

The current study examined the relative importance of socio- phase I volunteers was followed and, therefore, it is not surprisingeconomic conditions and psychological factors on the willingness that the surveyed population closely matches the demographicof healthy subjects to volunteer for their first-time participation in characteristics of participants in previous phase I studies per-a phase I study. The results suggest that high initiative, persistence formed by our unit (described elsewhere[3]); 56% were students,and exploratory tendencies, and low anxiety-trait may be stronger which is close to the percentage (52%) of university studentspredictors of participation than a low monthly income. among actual participants in phase I studies in our unit.[3] How-

Participants in phase I studies are a self-selected population ever, since reports of phase I studies usually do not includewho consented to participate and they may be potentially different information on the socioeconomic condition of study participants,from the population from which they are drawn. This self-selec- it is unclear whether our sample is representative of subjecttion bias is present in human research based in subject’s consent[28]

populations in other clinical pharmacology units and, therefore, inand may have implications for the interpretation and general- which manner the results of the current study may be generalized.izability of the results.[29] The magnitude and impact of a self- There were no relevant differences in the demographic orselection bias are difficult to evaluate because it is a heterogeneous socioeconomic characteristics between those subjects who de-phenomenon that can take various forms.[30] The current study clined and agreed to participate in the proposed phase I study.consisted of a survey. People who are asked to participate in a There was no influence of the subjects’ monthly income on theirsurvey may be reluctant to provide the researcher with any data, or willingness to participate. Although more subjects with earningsmay omit some items during the survey.[30]

above 100% of the reference income refused participation in theAmong the approximately 200 subjects who were contacted to proposed phase I study than those who accepted, there was no

participate in the survey, approximately 40% refused to provide difference between those who answered “Yes” and “No” amongany data. Therefore, there is no way to know whether or not these subjects with earnings less than 25%. Altogether, the resultsindividuals presented different characteristics from those who suggest that subjects with higher income tended to self-excludeconsented to answer the questionnaires. Among the 120 subjects from participation, but a low income was not a predictor ofwho consented to the survey, several subjects omitted some items; willingness to volunteer for participation in the proposed phase I7 subjects omitted question 2 (willingness to participate in the study.proposed phase I study). After excluding the 3 subjects with There is conceptual overlap among the psychological factorsprevious participation in a phase I study, 110 trial-naive subjects under study. Upon controlling for shared variance among thewere available for analysis. Most (54%) subjects refused participa- factors, the only unique predictors of participation were SEStion (“No” to question 2) and 21% accepted (“Yes”). A further initiative and persistence, CEI-T exploratory tendencies and STAI25% answered “Maybe”, but it is unclear whether this behavioural trait-anxiety. These traits appeared to be of particular importanceintention would have manifested itself in actual participation. in understanding the willingness to volunteer for participation in

In agreement with what has been reported in the literature[1,5] the proposed phase I study. The results of our study corroboratesand our own experiences,[3] financial reward was indicated by data suggesting that participants in phase I clinical trials may differmost subjects as the main motivation to volunteer for participation. from the population from which they are drawn[29] and are consis-However, other motivators were also given, such as the desire to tent with the theoretical framework. Participation in a phase Icontribute to the progress of medicine/science and curiosity; this is study may be perceived as a challenging situation that involvesin agreement with the results from other authors[31] and a previous discomfort and risk.[3] Since subjects with greater anxiety are morestudy from our group,[3] in which approximately 20% of actual likely to perceive a wider range of situations as threatening,[22] itparticipants in phase I studies indicated that they would have appears reasonable to expect subjects with higher trait anxiety tovolunteered for participation even if there was no financial reward. self-exclude from participation. On the other hand, since highlyHowever, one can expect that when these subjects are required to curious and self-efficacious subjects show a higher tendency to


374 Almeida et al.

12. Kashdan TB. Social anxiety dimensions, neuroticism, and the contours of positiveembrace and even thrive in challenging situations,[32] it seemspsychological functioning. Cognitive Ther Res 2002; 26: 789-910

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satisfying or even an appealing situation. isms and complex decision making. J Personal Soc Psychol 1989; 56: 407-15

14. Schwarzer R. General perceived self-efficacy in 14 cultures [online]. Availablefrom URL: http://userpage.fu-berlin.de/~health/world14.htm [Accessed 2008

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15. Bandura A. Self-efficacy. In: Friedman H, editor. Encyclopedia of mental health[reprinted]. San Diego (FL): Academic Press, 1998Subjects higher in initiative, persistence and exploratory ten-

16. Sherer M, Maddux JE, Mercandante B, et al. The self-efficacy scale: constructiondencies, and lower in trait anxiety were shown to be more willingand validation. Psychol Rep 1982; 51: 663-71

to accept participation in a phase I study. These personality traits17. Ferrari JR, Parker JT, Ware CB. Academic procrastination: personality correlates

played a more decisive role in the subjects’ willingness to with Myers Briggs types, self-efficacy, and academic locus of control. J Socvolunteer for a phase I study than the individuals’ socioeconomic Behav Personal 1992; 7: 495-502

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19. Sherer M, Adams CH. Construct validation of the self-efficacy scale. Psychol RepAcknowledgements 1983; 53: 899-902

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This study was financially supported by BIAL – Portela & Co, SA. The 264-77authors have no conflicts of interest that are directly relevant to the content of

21. Ribeiro JLP. Adaptacao de uma escala de avaliacao da auto-eficacia geral. In:this study.Almeida L, Ribeiro I, editors. Avaliacao Psicologica: formas e contextos.Braga: APPORT, 1995: 163-76

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The Role of Socioeconomic Conditions and Psychological Factors in the Willingness to Volunteer for Phase I Studies