RESUMO
BACKGROUND: Stability between internal and external biological regulators are essential to stable mood states. However, the literature needs studies investigating the effect of brief psychotherapies in the biological rhythm regularization. OBJECTIVE: To verify the capacity regulation of biological rhythms in two models of brief psychotherapy for the remission of depressive symptoms. METHODS: We conducted a randomized clinical trial with young adults aged 18-29 years old who met diagnostic criteria for depression according to the Structured Clinical Interview for DSM (SCID). In order to evaluate the biological rhythm the Biological Rhythm of assessment in Neuropsychiatry (BRIAN) interview was used; whereas the severity of depression was assessed by the Hamilton Depression Rating Scale (HDRS). The psychotherapy models consisted of two cognitive psychotherapies: Cognitive Narrative Therapy (CNT) and Cognitive-Behavioral Therapy (CBT). RESULTS: The sample consisted of 97 randomized into two models of brief psychotherapy. The patients regulated the biological rhythm from baseline to post-intervention (p=.001) and follow up (p=.003). We also found a positive moderate correlation between biological rhythm regularization and remission of the depressive symptoms (r=.594; p<.001). CONCLUSION: The two models of brief psychotherapies were effective in the remission of depressive symptoms as well as the regulation of biological rhythms in the follow-up of 6 months. LIMITATIONS: We did not assess genetic, hormonal and neurochemical factors. Also, we did not include patients in pharmaceutical treatment, and with severe symptomatology.