The objective of investigation was to determine whether patients with obsessive-compulsive disorder (OCD) resistant to drug therapy may improve their condition using intensive, systematic cognitive behavioural therapy (CBT) lasting six weeks and whether it is possible to predict treatment outcome using clinical and selected psychological characteristics.

From 66 OCD patients fifty-seven completed program. The diagnosis was confirmed using the structured mini international neuropsychiatric Interview. Patients were rated using the objective and subjective forms of the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), objective and subjective forms of the Clinical Global Impression (CGI), Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), dissociative experiences scale, 20-item Somatoform dissociation questionnaire and sheehan disability scale before treatment, and with subjective Y-BOCS, objective and subjective CGI, BAI and BDI at the end of treatment. Patients were treated with antidepressants and daily intensive group CBT for six weeks.

During 6-week intensive CBT program in combination with pharmacotherapy, there was significant improvement in patients suffering from OCD resistant to drug treatment. There were statistically significantly decreased scores of scales assessing severity of OCD symptoms, anxiety, and depressive feelings. A lower treatment effect was achieved specifically in patients who (a) showed fewer OCD themes in symptomatology, (b) showed higher level of somatoform dissociation, (c) had poor insight and (d) had a higher initial level of overall severity of the disorder. Remission of the disorder was more likely in patients who (a) had good insight, (b) had a lower initial level of anxiety and (c) had no comorbid depressive disorder.