The paper primarily focuses on differences in electroencephalogram (EEG) brain wave frequencies in the presence of symptoms of severe, chronic stress. In the case of a constant increase of stress triggers, it is important to quickly diagnose people who reveal difficulties coping with difficult situations in order to prevent the occurrence of mental disorders. One way to do this is to diagnose brainwave patterns. The study aimed to identify differences in the brainwave levels of participants reporting intense stress compared to the control group. Differences in brainwave frequency between the right and left hemisphere were also investigated in the study group. The study consisted of two stages. Initially, the study group was enrolled based on their level of stress intensity criterion determined by means of an interview (in which participants declared a sense of chronic stress) and high scores on the Perceived Stress Scale (PSS). The control group consisted of subjects with a low score. In the next stage brainwave frequencies were analyzed using quantitative analysis of EEG (electroencephalography, QEEG) recordings. QEEG is a quantitative analysis of the EEG record, in which the data is digitally coded and statistically analyzed using the Fourier transform algorithm. The results demonstrated that people reporting intense, chronic stress statistically significantly more often had higher frequencies of theta, alpha, and beta 2 waves, and a lower level of SMR. Significant differences in the frequencies of the waves in both hemispheres were also noted.