Two patients with borderline personality disorder experienced dramatic
dysphoric episodes after acute administration of intravenous
methylphenidate in a double-blind manner. These dysphoric episodes were
similar to those which occurred spontaneously under conditions of
psychological stress. Case histories and the behavioral and cardiovascular
effects of the infusions are described. The pharmacology of methylphenidate
is discussed in order to elucidate possible mechanisms mediating the
observed responses to this drug.