The goal of this multiple baseline case series study is to test the effect of imagery rescripting (ImRs) in Obsessive Compulsive Disorder (OCD) and Body Dysmorphic Disorder (BDD). Primary objective :The course of schema or core beliefs and change in OCD and BDD. To investigate the effectiveness of imagery rescripting on factors presumed to underlie the disorder, according to schema theory, and on OCD and BDD symptoms. Secondary objective: The change in OCD and BDD symptoms (full questionnaire), schemata and modes, core emotions, mood, affect and obtrusiveness of intrusion. Other objectives are research into the working mechanisms of imagery rescripting by collecting qualitative data from patients and their practitioner in a qualitative interview. For this study, a multiple-baseline single-case experimental design (SCED) is used testing different outcome variables in 18 OCD patients and 18 BDD patients. After a variable baseline period of 3-8 weeks participants will start twice weekly with imagery rescripting for 12 sessions, followed by a 6 week follow up. Participants will rate schema- or core beliefs and OCD or BDD severity on a visual analogue scale. In addition participants will rate core emotions, affect and obtrusiveness of the intrusion. Secondary we will asses four times questionnaires about OCD of BDD symptoms, depression and schemas en modes. After treatment participants will be interviewed about their experiences.