ABSTRACT
BPD is usually serious, as it jeopardises patients' security (Stone 1993; Paris 2002), worsens their quality of life and requires substantial recourse to medical and psychiatric services (Skodol et al. 2002). In the current DSM IV de®nition the fundamental trait is instability: in mood, interpersonal relations, self-image and affects. If instability is, together with impulsiveness, the distinguishing trait of the disorder, then BPD is the oxymoron of a PD, which DSM de®nes as a stable structure with constant change as a basic characteristic. A BPD model, therefore, needs to explain how this instability in behaviour, affects, relationships and sense of identity, which remains stable over time, arises. In this chapter we shall demonstrate how the interaction between metacognitive dysfunctions, states of mind and problematical interpersonal cycles can explain both the variability and selfperpetuation over time of BPD psychopathological phenomena. We shall then discuss the implications deriving from this model for individual psychotherapies.
