[Temporal evolution of passionate brain states in long-term couple relationships]

A growing body of evidence proposes that passion is a function of change in intimacy between spouses. In mathematical terms, passion is a function of the first derivative of intimacy over time. High passion occurs when intimacy is felt to be rising. Low passion occurs when intimacy is stable (either high or low). In the present article, we review the experimental evidences that attribute changes in passion in couple-longitudinal patterns as a function of a triadic model between passion, intimacy and personality traits. In light of this, future studies in couple therapy and human sexuality would need to take account of the consequences of both standard approaches in sexology and this triadic model in the understanding and treatment of decreases in frequency of sexual relationships in long-term relationships.