High levels of impulsivity represent a core feature of various psychiatric conditions, such as Attention Deficit Hyperactivity Disorder (ADHD), Borderline Personality Disorder (BPD), Impulse Control and Conduct Disorders, Bulimia Nervosa, Substance Use Disorders, and other maladaptive behaviors, like non-suicidal self-harm and suicidal behavior. The overall aim of our research is to carry out a trans-diagnostic study of impulsivity as a common behavioral risk factor, taking into consideration the different dimensions of impulsivity (motor, attentional, non-planning). The project investigates inhibitory neurocognitive deficits, electrophysiological correlates, childhood adversities and genetic vulnerability factors in the background of impulsivity.In this report, we describe the results of our pilot study which aims to compare impulsivity profiles, personality traits, and levels of aggression in patients with adult ADHD (aADHD) and BPD primary diagnoses, and healthy control subjects, based on self report questionnaires (Barratt Impulivity Scale, Cloninger Temperament and Character Inventory). We have also carried out analyses on the role of childhood adverse events in the background of impulsivity. Because of the predominance of female participants in the BPD group, we restrict our analyses to only female subjects (N=111 out of 152 patients overall).Comparing the three groups significant differences were observed in each impulsivity domain: higher levels of attentional and motor impulsivity were present in aADHD, while non-planning impulsivity was more characteristic to BPD (p<0.001). Using the Cloninger Temperament and Character Inventory aADHD patients reached significant higher levels on six subscales (novelty seeking, harm avoidance, reward dependency, perseverance, selfdirection, cooperation) than BPD patients (p<001). Childhood emotional neglect results in higher levels of impulsivity in adulthood (R=0.54, p<0.001) regardless of diagnosis.Impulsivity, as a diagnostic criterion of different psychiatric disorders is a heterogenous construct. Different characteristics of impulsivity are pronounced with respect to the condition it is part of. Studying impulsivity can improve our understanding of the etiology of different psychiatric conditions, which can result in more specific and effective therapeutic interventions