title: Who volunteers for phase I clinical trials? Influences of anxiety, social anxiety and depressive symptoms on self-selection and the reporting of adverse events.
abstract: OBJECTIVE
  To investigate the influence of anxiety, social anxiety and depressive symptoms on the willingness of healthy subjects to volunteer for phase I studies and to report adverse events.
  
  
  METHODS
  A group of healthy subjects who had never participated in a clinical trial ("Naïve Subjects") were invited to participate in a phase I study. All subjects were assessed for trait anxiety (State-Trait Anxiety Inventory, STAI-T), social anxiety (Social Avoidance and Distress, SAD, and Fear of Negative Evaluation, FNE) and depressive symptomatology (Beck Depression Inventory, BDI-II). Subjects who accepted the invitation to participate were compared with those who refused. The personality traits of a group of "Actual Participants" were examined, and the relation of these traits to adverse events reported during participation was evaluated.
  
  
  RESULTS
  A significant inverse correlation was found between the STAI-T (R = -0.203, p < 0.05) and SAD (R = -0.204, p < 0.05) scores and the willingness to participate. Naïve Subjects who refused the invitation to participate showed higher scores on STAI-T (Z = -2.600, p < 0.01) and SAD (Z = -2.524, p < 0.05) inventories. Logistic regression using BDI-II, STAI-T, SAD and FNE as covariates also showed that the only unique predictors of participation were the STAI-T (p < 0.05) and SAD (p < 0.01) scores. Significant positive correlations were found between trait anxiety and reporting of adverse events.
  
  
  CONCLUSIONS
  Participants in phase I studies are a self-selected sample defined by low trait-anxiety and social avoidance behaviors. This self-selection bias may affect the study results because less anxious subjects tend to report fewer adverse events. The characterization of a participant's personality traits may be important in phase I studies.
authors.affiliation: Department of Research and Development, BIAL, Portela & Co, SA, A Av. da Siderurgia Nacional, 4745-457 S Mamede do Coronado, Portugal. luis.almeida@bial.com
authors.forename: Luis
authors.initials: L
authors.lastname: Almeida
authors.forename: Todd B
authors.initials: TB
authors.lastname: Kashdan
authors.forename: Teresa
authors.initials: T
authors.lastname: Nunes
authors.forename: Rui
authors.initials: R
authors.lastname: Coelho
authors.forename: António
authors.initials: A
authors.lastname: Albino-Teixeira
authors.forename: Patrício
authors.initials: P
authors.lastname: Soares-da-Silva
mesh_terms: D000293:Adolescent; D000328:Adult; D001007:Anxiety / Q000523:psychology*; D017321:Clinical Trials, Phase I as Topic / Q000523:psychology*; D003863:Depression / Q000523:psychology*; D005260:Female; D006805:Human Experimentation; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D010551:Personality