The paper aims to consider a syndrome-based approach in methodology adopted for psychological phenomena in application to corporeity psychology. We present a study case of 290 patients with mitral valve prolapse. We endeavor constructioning of a psychosomatic syndrome, employing techniques for a qualitative and statistical data analysis of longitudinal clinical-psychological study. We bring evidence that the syndrome is of multi-level character, and that its structure is determined by several factors: a motivational factor (with domination of the infavoidance motive and unsatisfied self-approval need), a factor of emotional regulation disorders, and a psychophysiological factor. We argue that it is feasible to use a psychosomatic syndrome as a key method in approaching not only diagnostic but also prognostic problems both in clinical psychology and in medicine.