This thesis discusses the patient package insert (PPI), a folded sheet of paper in the drug package with a text which is supposed to be comprehensible for the general public. The PPI contains information on how the drug must be taken, on the risks of taking the drug, and a limited amount of information on whatthe drug is for. Belgium was the first country in Europe, together with Switzerland, to introduce PPIs. PPIs were first introduced in 1988 and the process was completed in 1992. In Europe, health authorities decided in 1992 that all medicinal product packages should contain a comprehensible insert. This decision is slowly but surely being implemented in all European countries. Similar developments did not take place in the US and other parts of the world, where medicines are distributed in bulk and dispensed without much information, even when dealing with powerful prescription drugs. During the introduction of PPIs in Belgium, a research programme wasconducted to evaluate this change in the way drug information was provided in the drug distribution system. This thesis provides an overview of the studiescarried out during that period. In addition, a number of other descriptive studies of the flow of drug information in specific patients groups is provided. Finally, a number of experimental studies is presented, which evaluate the impact of written drug information on patients? benefit/risk perception. The acceptance of a drug distribution system with mandatory PPIs in all drug packages will be evaluated on the basis of Belgium?s relatively long and welldocumented experience with PPIs. We address the following questions: what is the percentage of patients who read, accept and appreciate PPIs; what happens when a country changes from technical inserts with difficult jargon to comprehensible PPIs; what do we know about the impact of PPIs on patients knowledge and feelings about their drugs? In this thesis, an attempt is made to understand the mental processing of drug information which precedes patients' decisions and coping strategies, necessary for successful drug treatment. The question here is whether the PPI is capable of influencing the benefit/risk perception of patients. A further step is to study the impact of the PPI on behaviour. Here, other questions are at stake. Does the PPI have an impact on patients' reporting of health problems and side-effects, on their ability to carry out a treatment correctly and safely, on their adherence to therapy at the beginning of treatment, and on their motivation to continue crucial therapy? These questions are addressed only to a limited extent in this work, as we have focused on the preceding cognitive process of benefit/risk perception
