Most studies have tried to explain the school difficulties by analysing the intellectual factors that lead to school failure. However in addition to the instrumental capacities, authors also recognize the role played by other factors such as motivation. More specifically, the theory of achievement motivation aims to determine motivational factors involved in achievement situations when the students have to demonstrate their competencies. This paradigm attributes a central place to beliefs in order to explain children's behavior in academic situations. According to Dweck, it seems that beliefs about the nature of intelligence have a very powerful impact on behavior. These implicit theories of intelligence create a meaning system or conceptual framework that influences the individual interpretation of school situations. Thus, an entity theory of intelligence is the belief that intelligence is a fixed trait, a personal quality that cannot be changed. Students who subscribe to this theory believe that although people can learn new things, their underlying intelligence remains the same. In contrast, an incremental theory of intelligence is the belief that intelligence is a malleable quality that can increase through efforts. The identification of these two theories allows us to understand the cognition and behavior of individuals in achievement situations. Many studies carried out in the academic area show that students who hold an entity theory of intelligence (ie they consider intelligence like a stable quality) have a strong tendency to attribute their failures to a fixed trait. They are more likely to blame their intelligence for ne-gative outcomes and to attribute failures to their bad intellectual ability. In contrast, students who hold an incremental theory of intelligence (ie they consider intelligence as a malleable quality) are more likely to understand the same ne-gative outcomes in terms of specific factors: they attribute them to a lack of effort. This differential emphasis on traits versus specific mediators in turn fosters different reactions to negative events. Several studies have shown that entity theorists of intelligence are more likely than incremental theorists to react helplessly in the face of failure. They are not only more likely to make negative judgments about their intelligence from the failures, but also more likely to show negative affect and behaviors. This helpless response pattern is cha-racterized by a lack of persistence, and performance decrements. In contrast, incremental theorists, who focus more on behavioral factors (eg effort, problem-solving strategies) as causes of negative achievement outcomes, tend to act on these mediators. They try harder and develop better strategies and continue to work. Some authors have tendency to consider implicit theories of intelligence as a disposition or a stable dimension. But in the last few years, several studies showed that people's theories are not fixed traits; they are beliefs that may be influenced. These studies also suggested that students use the two types of beliefs and that the context determines the choice between the two types of theories. According to these authors, the psychological state of the student depends on dispositional factors but also on situational factors. Thus, several studies have tried to demonstrate that it is possible to modify experimentally implicit theories of intelligence and subsequent cognitions and behaviors by modifying situational factors. Several studies have demonstrated that it was possible to induce students to adopt one of the two theories of intelligence by presenting them a scientific article that compelling argued for either an entity or an incremental view of intelligence. The results showed that participants who had received the entity theory induction exhibited more evidence of a helpless reaction to failure. These studies show that some of the judgments and reactions associated with implicit theories can be experimentally induced by manipulating participant theories. However in the context of school difficulties, only few works have been conducted. We think that the model of the motivation of achievement would allow us to better understand maladjusted behaviors that engender failure and scholastic exclusion. In one study, reseachers have demonstrated that children with mental disorders are less likely than other children to hold an incremental theory of their intellectual abilities. Other studies have demonstrated that entity theorists interpret their bad results according to their global intelligence level by negatively judging their global abilities ("I think I am stupid"). It is interesting to note that these students make the same attributions as depressive students. These results reveal the need to determine systems of beliefs within populations with anxiety or depressive symptoms in order to characterise their motivational profiles. Indeed, we think that these symptoms contribute to modify implicit theories of intelligence and the nature of the subsequent scholastic achievement. Finally, we think that it is inte-resting to demonstrate the positive motivational effects of the experimental induction of the incremental theory. A series of studies showed that children's theories of intelligence expe-rimentally induced will influence their tendency to persevere in the face of failure. Like normally developing children, children with mental disorders were more likely to prefer challenging activities and report high levels of interest-enjoyment when the task was presented as one which is improvable. It suggests that although children with difficulties are pessimistic about improving their intellectual capacities, if a new task is introduced in a way that highlights the possibility of self-improvement (incremental theory), then they will pursue the challenge in an adaptive manner (strong perseverance, enjoy, and important interest). These results are very inte-resting. Indeed, highlighting an incremental theory had a po-sitive motivational effect on behavior in achievement situations. In addition, all these results also may open up several interesting perspectives for the treatment of learning disabi-lities. The results should lead to plan programmes of cognitive therapy in order to modify beliefs that underlie maladjusted achievement behaviors of children and adolescents in scholastic failure.