Is the Behavioural Inhibition System the core vulnerability for cluster C personality disorders?

The aim of the present study was to determine if Behavioural Inhibition Sys tem (BIS) functioning, as described by Gray (Gray, J.A.C. (1982). The Neuro psychology of anxiety: an enquiry into the functions of the Septo-Hippocamp al system. Oxford: Oxford University Press), would be a core vulnerability for cluster C personality disorders (PD), that is, if these patients would show a higher anxiety trait (i.e. in Gray's terms) than patients with other PD or without Axis II disorders. A total sample of 77 out-patients was ass essed with the Eysenck Personality Questionnaire, Sensitivity to Punishment and Sensitivity to Reward Scales, Karolinska Scales of Personality, and th e Structured-Interview for DSM-III-R Personality Disorders (SCID-II). Analy ses were conducted considering the following groups: presence of cluster C personality disorder/s, presence of clusters A/B personality disorder/s, ab sence of personality disorder (non-PD). As a second step, cluster C and non -PD groups were also subdivided according to the presence/absence of anxiet y or affective Axis I symptoms. Overall, results showed higher scores on an xiety trait-related scales in the cluster C group. However, only Somatic An xiety, Psychasthenia and Sensitivity to Punishment scales (SP) clearly dist inguished cluster C from each one of the other two groups. After a second a nalysis, only the Sensitivity to Punishment scale showed independence from Axis I status while discriminating between cluster C and non-PD patients. R esults were similar when only behavioural items from the SP scale were cons idered. From these results we can conclude that a higher BIS functioning wo uld differentiate cluster C personality disorders from patients with other PD or without PD, and that considering only the behavioural anxiety compone nt in their assessment, a low Axis I influence is obtained. (C) 2001 Elsevi er Science Ltd. All rights reserved.