Introduction: It is difficult to distinguish between posttraumatic and idiopathic psychotic disorders. After a traumatic brain injury, the incidence of psychotic symptoms is between 5-20%, with an average duration of 4 years. Delusions and auditory hallucinations are more frequent than negative and catathoniform symptoms. Despite the lack of strong scientific evidence, antipsychotic treatment seems the best choice, although there is a bigger risk of adverse effects. The prognosis does not seem to be related to the severity of the injury. Objectives and aims: We intend to illustrate the daily clinical practice, in which we find patients with important comorbidities, difficult differential diagnosis and therapeutic challenges. Methods: Using a case-report format, we describe a 26 year old patient with the following diagnostics: traumatic brain injury with secondary psychotic symptoms versus schizophrenia; alcohol abuse; cannabis dependence; pathologic gambling. We summarize complementary explorations, therapeutic management and evolution. Results: Along three years of follow up there is a preponderance of negative symptoms. Positive symptom exacerbations also occur, in coincidence with an increase of cannabis consumption. Due to lack of compliance, long acting antipsychotics are prescribed. Motivational Interview is used for the drug use disorders and the treatment compliance, achieving the goal of reducing cannabis consumption. Conclusions: Daily clinical practice brings us highly complex cases in which a multidisciplinary approach is very important. This particular case shows the differential diagnose difficulties between posttraumatic and idiopathic psychosis, and the troubles of clinical and therapeutical management in the dual pathology field.

IntroductionParaphrenia is a chronic psychotic disorder with a better-preserved affect and minimal disturbances of emotion and volition and a much less cognitive deterioration and personality changes.Objectives/aimsTo report a case with probable Paraphrenia and to highlight the importance of the differential diagnosis in a first psychotic episode.MethodsCase report and systematic review of the literature.ResultsWe report a case of a 41-year-old man without a past psychiatry history that was led to the psychiatry emergency department (PED), by officers, because of strange behaviour and aggressiveness towards his family. In the PED the patient said that his real father was his father-in-law and that his ex-wife was his sister. His mental exam revealed disinhibition, disorganized speech with slightly mood elation, persecutory, mystic and influential delusions with various delusional interpretations. After being admitted to the psychiatric ward, in compulsatory care, he began treatment and a medical work up was completed. According to the family the patient had begun this strange behaviour four years prior. During the hospitalization it became clear that the patient was experiencing imaginative-confabulatoric multi-thematic delusions, sometimes interviewer guided, without showing cognitive deterioration and retaining his personality.ConclusionsThe diagnosis of atypical psychosis or psychosis not otherwise specified is not satisfactory since it agglutinates different conditions together. Paraphrenia is a well-established concept and should be used in order to define a group of psychotic patients who exhibited characteristic symptoms of schizophrenia, minus personality impairment and slower cognitive decline.Disclosure of interestThe authors have not supplied their declaration of competing interest.