ABSTRACT
Multidimensional and complex nature of obsessive compulsive disorder [OCD] requires assessment and usage of modern treatments. This study was planned to investigate the effectiveness of Wells' metacognitive model on thought fusion symptoms in patients with OCD as an important aspect of metacognitive beliefs. This semi-experimental study was conducted with pretest-posttest and follow-up design, using control group. From all OCD patients visited in psychology clinics in Shiraz city, south western part of Iran in 2008, 24 patients were selected through the objective sampling method and randomly divided in two equal experimental and control groups. Experimental group experienced 8 weeks of Wells' metacognitive therapy, while control group were just followed. Thought fusion instrument [TFI] was used in pretest, posttest and 2-month follow-up as the study instrument. Data were analyzed by descriptive indices and multivariate analysis of covariance, using SPSS software. The experimental group showed significant decreases in thought fusion general score and its triple items in post-test and follow-up, compared with control group [P<0.001]. Wells' metacognitive model is beneficial in decreasing thought fusion in OCD patients