Personality disorder in younger adult psychiatric in-patients is known to prolong the in-patient stay, impede recovery and increase health care costs. There is a significant association between the number of disordered personality traits and medical resource utilization. However, this has not been extensively studied in the elderly, where personality disorder is usually un-diagnosed or ignored. It has previously been felt that personality disorder ‘burns out’ in old age, but there is no data supporting this. Our study is to determine the prevalence and types of personality disorder in elderly psychiatric in-patients and the impact if any it has on their ultimate outcome. Previous work has found that a high percentage of older psychiatric in-patients (50%-60%) had a personality disorder. Others have also confirmed a poorer outcome of axis I disorders in personality-disordered clients. However, this could vary widely resulting from different sample characteristics, different measures and different diagnostic criteria. The presence of personality disorders has also been shown to adversely affect relationships, which may also be deleterious to recovery, as supportive relationships improve/hasten recovery. Our hypothesis is that those elderly psychiatric in-patients with comor-bid personality disorders will take longer to treat, and their recovery will be less complete than those without personality disorders. A single case series study of adult psychiatric in-patients is being undertaken to determine the prevalence of personality disorder and the effect on treatment of their axis I disorder. This study will contribute to our knowledge of the effects of personality disorder in elderly psychiatric in-patients and should provide clues as to how these conditions could be managed to affect improved outcomes.