Background: Previous findings showed that suicidal patients elicit mostly negative countertransference such as distress, hopelessness, feelings of inadequacy, and apprehension, and that a concurrent personality disorder is associated with more feelings of entrapment and mistreatment, among other adverse reactions. No studies were however conducted on instant countertransference (iCT), i.e., after a single encounter, for example in an emergency setting. We aimed to evaluate the impact of suicidal ideations, self-harm and presence of personality disorders on instant Countertransference (iCT). Methods: Caregivers rated their iCT with two validated and standardized questionnaires after a first emergency or outpatient consultation. Suicidal ideation, selfharm and personality disorders were tested as predictors for iCT in a multivariate and multilevel analysis. Results: Thirty caregivers rated their iCT towards 321 patients. Personality disorders and suicidal ideation, but neither recent nor past history of self-harm, predicted iCT. Common iCT included tension, lack of self-confidence and feeling of being tied. iCT specifically associated with suicidal ideation included distress, lack of hope, confusion, and sense that the patient's life had little worth. In contrast, iCT towards patients with personality disorders suggested tension in the therapeutic relationship (low affiliation with patient, anger, disappointment, devaluation). Limitations: Caregiver's characteristics were not considered in the analysis. Furthermore, while countertransference also includes unconscious phenomena, only conscious iCT was assessed. Conclusions: Patients with suicidal ideation and personality disorders elicit common but also specific negative iCT. Mental health institutions need to devote specific resources (such as clinical supervision and training) to help caregivers manage their iCT.