likely interfere illness psychiatric participation medical clinical study patients opinion subject study treatment protocol france investigator following french subjects condition preclude participation investigator condition opinion medical study trial safe clinical condition medical investigator opinion participation study interfere psychiatric protocol compliance interfere cooperate likely deemed ability participate condition mental investigator sign coexisting likely condition medical procedures interfere results study psychiatric hazard results interfere interpretation medical likely participation laboratory investigator history including patient study investigator participate treatment disease medical therapy protocol unlikely extenuating circumstance significantly additional interfere opinion illness compliance condition medical psychological medical condition compliance investigator compromise participation social opinion study