Commentaries on the letter to the editor

In the letter by Scorza and Cavalheiro1, the authors posit that the use of psychoanalysis for neuropsychiatric syndromes “has a direct positive influence” on neurogenesis. Yet, the authors acknowledge that the putative mechanisms to explain the alleged role of psychoanalysis on neuroplasticity remain “still poorly explored”. In a letter addressed to Wilhelm Fliess in April 1895, Sigmund Freud manifested his willingness to integrate the canons of brain anatomy and physiology with his ideas on psychopathology in order to propose a theoretical model grounded on neurobiological processes2. Months later he sent the draft of his ideas on this topic to Fliess, who retained the manuscript. This piece, later entitled “Project for a Scientific Psychology”, was published posthumously in 19503. On that account, Freud prophesied the significant progress of neurosciences in the last decades, which promoted a better understanding about the way the brain responds to environmental stimuli, psychosocial factors as well as therapeutic interventions. The recent debate on the applicability of empirical research as a way to scrutinize the effectiveness of psychoanalytic as a treatment modality has been a contentious one4. Although some authors have advocated that the assumptions of psychoanalysis and its proclaimed therapeutic effectiveness should be examined in experimental testing conditions5, others understand that the benefits of psychoanalysis are axiomatic and not amenable to enquiry via empirical research methodology6. In any case, if psychoanalysis does in fact produce significant neuroplastic changes, as highlighted by Scorza and Cavalheiro1, this attribute per se is not a tantamount to treatment effectiveness. After all, neurochemical and neuroplastic changes happen in the brain in response to a plethora of stimuli and interventions. The seminal studies conducted on Aplysia sensorimotor synapses revealed that synaptic transmission may induce neuronal structural changes. These neuronal changes are generated via a cascade of neurochemical phenomena, which subsequently activate immediate early genes, increase neural cell adhesion molecules (NCAMS), resulting in neuronal reconfiguration. These neuronal modifications happen as a response to a series of environmental influences, particularly in the context of stressful stimuli7. Results from animal studies have revealed distinct mechanisms of neuroplasticity: stress may produce excessive growth in the amygdala, while generating opposite effects in hippocampus8. In fact, there is growing evidence indicating that interventions designed to promote favorable emotional states may achieve its outcomes via neuroplastic changes in the brain7. These interventions include cognitive therapy9, meditation10, and physical exercise11. It remains unclear though whether these interventions improve neurological function and behavior or whether they simply mitigate the effects of stress on the brain8. Interface between psychoanalysis (and other psychotherapies) and brain plasticity: is there a state of the art?