OBJECTIVE: Two major psychodynamic theories of the etiology of
borderline 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 of the child. This study is an attempt to examine these putative
risk factors empirically, using epidemiologic methods. METHOD: Mother-child
interaction, father-child interaction, maternal personality, and adolescent
diagnoses of personality disorders were measured on two occasions, 2.5
years apart, in a random sample of 776 adolescents. RESULTS: Maternal
inconsistency in upbringing of the child predicted a persistence or an
emergence of borderline personality disorder, but not of any other axis II
disorder. However, this effect occurred only in the presence of high
maternal overinvolvement. Neither maternal overinvolvement nor maternal
inconsistency alone predicted emergence of borderline personality disorder.
Pathological features of maternal personality did not account for the
combined effect of maternal overinvolvement and inconsistency on borderline
personality disorder. CONCLUSIONS: The two child-rearing risk factors
hypothesized to be important by two psychodynamic models of borderline
personality disorder were found to be pathogenic only when they coexisted.
Their effect could not be accounted for by the biological or environmental
vulnerability represented by maternal borderline personality traits.