Investigation of the interaction of mental states and cognitive processes in the classroom allows us to solve the problem of increasing the effectiveness of training by activating cognitive processes and management of students' mental states. This article is concerned with the most general patterns of interaction between mental state and intellectual processes in students' academic activity. On the basis of the structural-dynamic approach two forms of influence on the intellectual process by current mental state have been identified. The first type of influence is on the transformation of the form of the process, reducing its resilience and degree of organisation as increasingly becomes integrated into the contingent mental state. The second type of influence is associated with the positive, neutral or negative dynamic of the productivity of separate indicators of the cognitive processes. The obtained results may be of interest for investigators studying the problem of mental states as well as for teachers and students concerned with the psychological aspects of training.