The study of negative emotional states (anxiety and aggressiveness) proposed in the article was conducted in grades 10-11 (N=54). In the course of the study, an observation program was developed and used on the topic "USE as a factor in the occurrence of negative emotional states in high school students." The purpose of the observation, the object, the subject, the situation of observation, the number and duration of observations, the list of indicators, signs of external manifestations of anxiety, aggressiveness and fear among students were determined, questions were drawn up. Anxiety (according to manifestations of discomfort, restlessness; repetitive involuntary movements; uncertainty in response) and aggressiveness (aggression towards others, physical aggression, irritability) were studied. The results showed that the indicators of anxiety and aggressiveness in the 11th grade are higher when there is an active preparation for the exam. In the 10th grade, the preparation is still not so intensive, and the students get the impression that the exam is still far away, the level of the studied indicators is relatively lower. However, a number of indicators ("uncertainty in the answer", "irritability") do not differ much from the 11th, which may be due to the natural level of school anxiety characteristic of high school students of this particular school. Other researchers also note that recently the number of schoolchildren with a high level of negative emotional states (anxiety, fear, aggression) has significantly increased, which can adversely affect intellectual and educational activities, especially during the preparation and passing final exams.