The article considers the possibility of applying the fractal self-similarity principle to reveal the influence of the individual annual rhythm on the processes of human vital activity. An interdisciplinary approach to the study of the states of mental activity as a property of the psyche to the reproduction of the same structures at different levels of its integrity is proposed. A unique model of cyclicity of vital activity from the position of psychological science is presented. A brief review of the results of the authors' studies, pointing to the fractal nature of human states and proving the existence of the relationship between the individual annual cycles of the subjects, the activity and the effectiveness of their vital activity is made. The problem of developing research methods is discussed. The empirical data obtained by the authors on different samples of the subjects is presented, which testifies the existence of a connection between the three life cycles of a person: the daily, individual, and full life cycles. On the basis of the obtained results, conclusions are drawn on the example of the fractal nature of the individual life cycle regarding the advisability of applying the principle of self-similarity in studying various phenomena of the human psyche as a nonlinear dynamic system.