THE IMPACT OF MOTHER-CHILD INTERACTION ON THE DEVELOPMENT OF BORDERLINE PERSONALITY-DISORDER

Objective: Two major psychodynamic theories of the etiology of borderl ine personality disorder posit two aspects of mother-child interaction as uniquely pathogenic: maternal over-involvement with the child and mismanagement and inappropriateness of maternal guidance and support o f the child. This study is an attempt to examine these putative risk f actors empirically, using epidemiologic methods. Method: Mother-child interaction, father-child interaction, maternal personality, and adole scent diagnoses of personality disorders were measured on two occasion s, 2.S years apart, in a random sample of 776 adolescents. Results: Ma ternal inconsistency in upbringing of the child predicted a persistenc e or an emergence of borderline personality disorder, but not of any o ther axis II disorder. However, this effect occurred only in the prese nce of high maternal overinvolvement. Neither maternal overinvolvement nor maternal inconsistency alone predicted emergence of borderline pe rsonality disorder. Pathological features of maternal personality did not account for the combined effect of maternal overinvolvement and in consistency on borderline personality disorder. Conclusions: The two c hild-rearing risk factors hypothesized to be important by two psychody namic models of borderline personality disorder were found to be patho genic only when they coexisted. Their effect could not be accounted fo r by the biological or environmental vulnerability represented by mate rnal borderline personality traits.