['One risk is ok. Are three a sure damage?" Health education's obstacles in the prevention of multiple risks].

Health education can have unexpected effects, sometimes even harmful, in particular when dealing with, on the one hand, multiple risk pathologies and, on the other, one risk factor that is connected to various different pathologies. Certain unexpected effects can be the result of too much information on prevention or when prevention is too focused on one target. In the first scenario, relativity of the information could arise faced with certain health risks or be used against public health objectives. When information is too focused on one target group, it can create discriminatory reactions for the groups at risk, which can translate into denial of the potential risk by those outside of the target group. Other prevention actions can have an unexpected effect, or none at all, because the target behavior is considered functional for the individual. In order to prevent a risk behavior, it is necessary to take into account the threats it is meant to avoid (concurrent risks) and other risk factors meant to attain the same objectives (substitutable risks). In order to understand and avoid different obstacles, people's beliefs and knowledge, which are often rooted in daily behavior and hence difficult to change, must be taken into account. It is also important to situate behavior in context, identifying its function and the concurrent and substitutable risks, which means researching as well the social sciences. In the future, the need for a global health approach will be evident because prevention of risk behaviors increasingly refers to multiple risks in one same pathology as well as concomitant prevention of multiple pathologies.