[How detailed information and how long consideration time do the potential trial subjects want?].

Questionnaires were sent to 508 citizens in Copenhagen county and given to 200 patients attending two out-patient clinics. Questions concerned attitudes and preferences towards either a short or a more detailed information form about an invented trial, and preferences regarding required time for reflection before giving informed consent. One sixth of responders were satisfied with the short form, while about three quarters preferred the long form. Three quarters of the non-hospitalized citizens and the patients from one of the out-patient clinics required at least 24 hours before answering about consent. Among responders in the other outpatient clinic half of the patients only required 15 minutes, or stated that they could answer at once. We conclude that written information to trial patients should be detailed, as a majority of potential research participants prefer this. At least 24 hours should be given before an informed consent is obtained.