The concept of borderline personality

To the Editor

Dignam’s defence of the diagnosis of borderline personality disorder (Dignam, 2013) is lucid and admirable but wrong-headed, as is his criticism of both a trait-based and dimensional system of classifying personality disorder. The logic is simple. Normal personality is best classified by traits – so-called normal personality and personality disorder are not qualitatively different – and so personality disorder is best classified by a trait-based system with dimensions of severity. Borderline personality disorder is a catch-all syndromal diagnosis (Tyrer, 2009); it includes mood and identity disturbance, self-harming behaviour and episodic hostility, and is so heterogeneous that it rarely exists alone (Fyer et al., 1988), hindering treatment and confounding guidelines (American Psychiatric Association, 2001; National Collaborating Centre for Mental Health, 2009; Tyrer and Silk, 2011). The time is ripe for a radical change in thinking for all personality disorders (Tyrer, 2012). Nearly three-quarters of psychiatrists in the field dislike the existing categorical system and feel it should be changed in favour of a dimensional one (Bernstein et al., 2007) and, in the revised International Classification of Diseases (ICD)-11 classification, borderline personality disorder and other categories will no longer exist (Tyrer et al., 2011). The patients with borderline syndrome will still seek treatment but they deserve a better classification system than exists currently to guide their management.