Katja Hannestad Høst Supervisors: Tor endestad and Else-Marie Augusti Abstract Objective: cognitive impairment and difficulties in emotion regulation are proposed as a vulnerability factors in relation to a wide spectre of psychopathology. A close interplay between executive functioning (EF) and emotion regulation abilities has been emphasised, and development of standardised methods for research targeting emotion regulation difficulties in relation to EF dysfunction is imperative. An emotional conflict task is proposed to tap underlying EF factors in emotion regulation difficulties, potentially crossing diagnostic borders. So far, the task has only been used in a few clinical studies, and only with adult patients. Hence, its potential should be investigated within a broader range of disorders as well as age groups. Method: existing data from three clinical studies (on Trauma, Continuous Fatigue Syndrome and Anorexia Nervosa) were combined in order to provide an exploration of the emotional conflict task in adolescents as well as in clinical populations not earlier targeted with this task. Furthermore, effects of emotion within the current task design were investigated with regards to age and clinical status for the first time. Results: no associations between clinical status and task-performance were found but, but performance improved with age. The conflict adaptation effect (CAE), which the task is primarily designed for, did not emerge consistently across studies. Furthermore, effects of emotion modulated by age, deviating between the pooled test group and the pooled control group was also found. Conclusion: results indicate the tasks potential for investigating emotion-cognition interaction in normative development. However, concerns are raised with regards to the validity and utility of the CAE construct, and effects of emotion related to age and clinical status violate a basic assumption in the paradigm. These issues needs to be addressed and clarified in future studies, particularly if the task is to be used in research on a broader spectre of disorders and/or in developmental research.