The role of environmental influences in the complex relationship between borderline personality disorder and attention-deficit/hyperactivity disorder: review of recent findings

BACKGROUND: In recent years, the existence of possible developmental pathways from childhood Attention-Deficit/Hyperactivity Disorder (ADHD) to adult Borderline Personality Disorder (BPD) has been suggested. The existence of common genetic factors has been described but there is little evidence on the role of environmental factors in the possible transition from one disorder to another throughout life. The main goal of this work is to review the literature about the existing evidence on childhood traumas as factors that mediate the risk of developing BPD in children with ADHD. METHODS: A literature search was conducted using PubMed, Science Direct and PsychInfo databases. Criteria included studies of BPD and ADHD relationships and childhood traumas as environmental influences from epidemiological or clinical samples. RESULTS: The review only identified 4 studies that matched the search criteria. All studies retrospectively analyzed childhood traumas, and adult patients with BPD, with or without comorbid ADHD, were the most frequently mentioned. The analyzed evidence reinforces the relationship between the number of childhood traumas and higher clinical severity. Three of these analyzed studies describe an increased the risk of children with ADHD who report emotional and sexual traumatic experiences to develop BPD in adulthood. CONCLUSIONS: The experience of traumatic childhood events, especially those of an emotional type, may have a mediating effect of an increased risk of developing adult BPD in childhood ADHD patients. However, to consider them as risk factors, more studies, and especially longitudinal studies, are necessary to clarify the probable transactional process between the two disorders. Evidence from these studies may be helpful to develop early intervention programs to reduce the functional impairment associated with the two disorders.