Simon, W. (2009). Follow-up psychotherapy outcome of patients with dependent, avoidant and obsessive-compulsive personality disorders – a meta-analytic review. International Journal of Psychiatry in Clinical Practice 13 (2), 1-12,

Abstract:
Assessing the number of patients who maintain their gains after the completion of therapy has been of interest to psychotherapy outcome researchers. The current study examines evidence related to the maintenance of treatment gains in individuals diagnosed with Cluster C personality disorders. Fifteen studies, published between 1982 and 2006, met the criteria for inclusion. The effect size standardized mean difference statistic was applied. In the majority of cases, most of the improvement occurred between pretreatment and posttreatment. However, social skills training often produced effect sizes that were larger for posttreatment follow-up. The study indicates that therapy gains are usually maintained at follow-up for Cluster C clients treated with cognitive-behavioral and psychodynamic approaches as well as social skills training. Uncertainty remains whether DPD, AVPD or OCPD patients benefited most from therapy.
Keywords: psychotherapy, follow-up, cluster C, meta-analysis