Objective: Obsessive-compulsive disorder at clinical levels has elevated symptoms that result in deteriorated psycho-social functions. This study was aimed to examine the effectiveness of cognitive analytic therapy on symptoms severity of obsessive-compulsive disorder.

Methods: This exploratory empirical study was a clinical trial that used quasi-experimental design to systemically investigate the differences in the obsessive-compulsive symptoms before and after one psychotherapeutic intervention. Twenty patients with obsessive compulsive disorder were chosen among patients who resided in Ravan-Sabz Center of Psychiatric Rehabilitation in Semnan City, Iran from 2012 to 2013. The patients were selected by inconvenience sampling and randomly assigned to experimental and control group. Participants initially completed the Socio-demographic Questionnaire and interviewed by the Structured Clinical Interview for DSM-IV-TR Axis I Disorders. Then, the Yale-Brown Obsessive-Compulsive Scale was administered in baseline, post-treatment and followup. Treatment group merely received 16 sessions of group cognitive analytic therapy and eventually both groups were assessed in post-treatment and a three- month follow-up.

Results: Mixed analysis of variance with repeated measures showed that symptoms severity of obsessive compulsive disorder was significantly decreased at post-treatment and three-month follow-up in the treatment group as compared to the control group (F1,18=15.05, P<0.001). The interaction of intervention and factor of time resulted in decreased symptoms severity in posttreatment and follow-up (F2,36=22.53, P<0.001).

Conclusions: The group cognitive analytic therapy is an effective and long-standing therapy for symptoms management of obsessive compulsive disorder. Moreover, these results have some implications for clinical practice including the necessity for further randomized controlled trials in order to verify the findings