The aim of this paper is to discuss theoretical issues as well as clinical and experimental evidences regarding the nature versus nurture debate of the origins and development of emotional disturbances. The etiological equation as proposed by Freud at the turn of the 20th century is presented. Clinical and experimental evidences, which support the notion of the etiological equation, are also presented. These evidences indicate the importance of the genetic makeup that regulates serotonergic activity as well as traumatic experiences that occur inside or outside the critical period. Environmental interactions, such as social support, can also relieve the expression of emotional dysfunction. A mathematical model of the etiological equation is presented through a logistic regression in which all these parameters are incorporated.
Nurture; etiologic equation; neurosis; depression; evolutionary theory; critical period; resilience; Neuropsychoanalysis
