Context and objectiveDepression is a major public health problem, for the treatment of which psychodynamic psychotherapies are receiving renewed interest. However, there are still few studies focusing on the effectiveness of psychoanalytic and psychodynamic group therapies for depressed patients. In this article, we will shed a light on the determinants of the effectiveness of a brief, 4-session psychodynamic intervention (BPI) led by a group of therapists, as inspired by the Lausanne model, on the symptomatology and experience of patients in acute depressive crisis. Material and methodsThe patients who accepted to participate in this research were interviewed in a therapeutic setting. The participants, all mental health users most of them (88%) not hospitalized, were informed of the research and consented to it using a free and informed consent form. Our sample consisted of 32 patients with an average age of 43.81years and a sex ratio of one man for every four women. The therapists involved gathered data by completing several hetero-questionnaires after each therapy session: MADRS, ESM, EFP, HAQ-IT, EDICODE, Counter-Transfer Scale. The SPPS software (V21) was used to analyze the data. ResultsThe MADRS score dropped by more than 11 points after the four sessions. The depressive symptomatic intensity therefore decreases significantly after the brief psychodynamic intervention. Patients still suffer with severe depression, as evaluated with a Beck scale, but the decrease of more than nearly two standard deviations indicate substantial improvement after four sessions. This improvement also corresponds to a more positive and committed self-reported countertransference of the therapists’ towards the patients. DiscussionInsight increases in patients who have been treated by group BPI sessions. They also show greater behavioral and psychic activity. This effect could be linked to a particular mechanism that we will call “unfreezing”, which allows the patient to regain sufficient capacities of psychic elaboration, insight, interhuman communication (affective, relational and psychic) to go forward in his own life. We define the unfreezing as the exit of the depressive inhibition following the sharp increase of the patients’ insight, as allowed by the group BPI, which focuses on the discourse and the lived experience of the patient. The unfreezing can be seen in that (1) Though the patient is not completely autonomous, he reports greater activity and more satisfactory human interactions. (2) His speech is more focused and structured, as opposed to the major intellectual inhibition and abulia characteristic of depressive crises. Limitations and conclusionsThe validity of a consensus between therapists could be called into question because of the weight of countertransference when dealing with patients in acute depressive crisis. However, the BPI system in a group of therapists seems to be an effective therapeutic aid in the “unfreezing” of the psychic processes in depressive patients. Our results point out the importance of jointly aiming at symptomatic improvement and therapeutic alliance, focusing not only on the symptoms, but more specifically on the patient's psychic dynamics.