The recognition and differentiation of conversion and factitious disorders could be difficult when they coexist with physical problems and their psychopathology is not evident. We present two illustrative cases of patients who share the existence of neurological disorders and present a similar psychiatric semiology, which is phenomenologically different related with their physical deficits. The psychopathological assessment was made by means of a standardized instrument for diagnosis (SCAN) and suitable paraclinical techniques for each case. The test MMPI (Minnesota Multiphasic Personality Inventory) was used in both cases, and an exploration with Thiopental was carried out in one of them. The pertinent differential diagnosis, the advantages of coordinated interdisciplinary interventions in order to elucidate these mental disorders, and the convenience of using appropriated psychometric instruments and exploratory methods are expounded in the present paper.