The lack of a medically grounded approach to personality disorder and its management has led to its comparative neglect as a topic by many clinicians in the UK. In this article we present evidence that personality disorders are, like other mental disorders, the social manifestations of a pathological process. This process presents with characteristic clinical features that are developmental in nature. These cause disturbances in arousal, affect and reality testing that have an impact on interpersonal social functioning. Personality disorder may therefore be conceived of primarily as a socioemotional disability, not dissimilar to Axis I conditions.