The study of the relationship between stress, psychosocial adaptability and academic achievement in adolescents is a research area that is rapidly developing. Yet, few studies analyze the individual differences existing in the way adolescents experience stress. In order to compensate for this lack of information, this study examines the changes observed over time in the personal resources, academic achievement and psychosocial adaptability of five groups of students while their stress level was stable (low, average or high), increased or decreased between the 9th and 11th grade. The first results indicate that the higher stress level group is made up of mostly girls from secondary three (grade 9) and secondary five whereas the lower stress level group is mostly made up of boys. The results regarding the longitudinal participants show that the best trajectory towards academic achievement, the development of positive personal resources and psychosocial adaptability is associated to the group of students whose stress levels decreased between the middle and the end of high school (increase in general academic achievement, self-esteem and autonomy; decrease in interiorized disorders).  However, the worst trajectory was taken by the group of students whose stress level increased during that same period of time (decrease in French marks (mother-tongue language); increase in the use of unproductive or social coping strategies; intensification of interiorized disorders). These results suggest that it is necessary to develop practical intervention tools in order to avoid the development of stress or even worse that it intensifies during adolescence.

It is without a doubt that adolescence is a very stressful developmental period considering the numerous changes that adolescents go through. Some of these changes are puberty, development of the sense of identity, reorganization of interpersonal relationships (family, friends, and intimacy), relations with authority, and academic achievement expectations. The way of dealing with these normative periods of stress without developing psychological distress, such as internalized or externalized disorders, depends in part on the intensity, the length and the frequency of other stressors. However, it also depends on the efficiency of coping strategies as well as personal, academic, and social protective resources that are available to each student. Situations considered stressful by adolescents negatively affect their mood, their physical health and their psychosocial and academic adaptation. For example, some studies such as the one conducted by Reynolds, O’Koon, Papademetriou, Szczygiel and Grant (2001) as well as the one by Schmeelk-Cone et Zimmerman (2003) identify a relationship between stress and interiorized and/or externalized symptoms. Even though the relation between stress and distress has been relatively well documented, few researchers have studied the patterns of stress over time in relation to psychological outcomes and personal resources among adolescents. Some adolescents would report consistently high levels of stress, while others would report consistently low levels of stress, whereas others would report a changing pattern over time. What appends in the psychological profile and the personal resources if stress levels remain stable, increase or decrease over time? Schmeelk-Cone and Zimmerman (2003) found that adolescents with chronic levels of stress reported more anxiety and depression, engaged in antisocial behaviors, and reported less active coping strategies than youth in other trajectories. Over a three year period, stress patterns were analyzed among French-speaking teenagers from Quebec. Three stress level groups (low, moderate, high) from a public high school were observed in secondary three (grade 9) and secondary five (grade 11). In this longitudinal study, we created five groups of students using these three stress levels in order to show the evolution between secondary three and secondary five. We obtained the low-low group, the moderate-moderate group, the high-high group, the group of increasing stress levels and the group of decreasing stress levels. Several standardized questionnaires were used in this study: daily hassles (Plancherel, Bettschart, Bolognini, Dumont, & Halfon, 1997), coping strategies (Frydenberg & Lewis, 1993), psychopathological disorders (Achenbach, 1991), self-esteem (Rosenberg, 1965), optimism (Scheier & Carver, 1985), autonomy (Deslandes, 1999), psychoactive substances consumption (MEQ adaptation, 1994), as well as school report cards and the number of hours spent working at a part-time job. In secondary three and five, the statistical analysis indicates a significant difference between the three levels of stress groups: students with a low level of stress used less unproductive coping compared to those that showed moderately or severely high levels of stress. They also showed more autonomy, optimism and self-esteem whereas they had less interiorized (withdrawal, anxiety/depression) and externalized disorders (aggressiveness). The first results indicate that the higher stress level group is made up of mostly girls from secondary three (grade 9) and secondary five whereas the lower stress level group is mostly made up of boys. The results regarding the longitudinal analysis reveal statistically significant differences between groups : 1) students who had low levels of stress in secondary three and secondary five showed a significant increase of their criminal behaviour between the two measures compared to the four other groups; 2) students who had moderate levels of stress in secondary three and secondary five did not show any statistically significant changes in regards to all the variables measured; 3) students whose stress levels decreased between secondary three and secondary five saw their academic achievement as well as their self-esteem and their autonomy significantly improve whereas the presence of interiorized disorders (total score) as well as their anxiety/depression levels diminished; 4) students whose stress levels increased in secondary five saw their marks diminish in French (mother-tongue language) whereas they used social or unproductive coping strategies more often, they also showed more interiorized disorders (total score, social withdrawal and anxiety/depression); 5) students who had chronically higher levels of stress in secondary three and five did, despite everything, improve their autonomy. If they experienced less interiorized disorders (total score, anxiety/depression), it is completely the contrary regarding their criminal behaviour which increased between the middle and the end of high school. In conclusion, we found that individuals may have differing stress trajectories over a three year period, either consistent patterns or displaying changes over time. From an intervention standpoint, the longitudinal nature of this study and a person-oriented approach has allowed us to firstly identify and to secondly promote the factors associated with positive trajectories in adolescent development. This study provides evidence that future research on individual differences in stress patterns over time will provide valuable insights for the development of interventions that prevent the negative effects of stress on adolescent development, mitigate the factors that may increase stress, and promote factors that help youth adapt to the stress they will inevitably face as they develop into young adults.