A prototypic nonprototype of a personality disorder.

The prototype model has been suggested as an alternative to the traditional categorical model of classification. A series of studies have been performed by Blashfield and his colleagues to identify cases that are prototypic of the DSM-III-R personality disorders. A case that led to diagnostic disagreement was based on the 1985 German movie Zuckerbaby ("Sugarbaby"). In earlier research, the most popular diagnosis for the case was dependent personality disorder, although schizoid, schizotypal, and borderline were almost as frequent. In the current study, the case was presented in cumulative steps to 93 randomly selected clinicians. After each step was presented, clinicians were asked to diagnose the case. With the stepwise presentation format, borderline personality disorder was the most common diagnosis. Chi-square analysis showed that, if clinicians had chosen borderline as a diagnosis by step three, they were likely to keep this decision for the rest of the case. A social-cognitive model was used to explain these results.