Background: Compared to cluster B personality disorders, the assessment and treatment of people with obsessive-compulsive, dependent, and avoidant personality disorders (cluster C) is given little attention in the field of research and clinical practice.
Aim: Presenting the current state of affairs in regard to cluster C personality disorders.
Method: A systematic literature search was conducted using the main data bases.
Results: Cluster C personality disorders are present in approximately 3-9% of the general population. In about half of the cases of mood, anxiety, and eating disorders, there is co-morbid cluster C pathology. This has a major influence on the progression of symptoms, treatment effectiveness and potential relapse. There are barely any well conducted randomized studies on the treatment of cluster-C in existence. Open cohort studies, however, show strong, lasting treatment effects.
Conclusion: Given the frequent occurrence of cluster C personality disorders, the burden of disease, associated societal costs and the prognostic implications in case of a co-morbid cluster C personality disorder, early detection and treatment of these disorders is warranted.