It has been a clinical case of a polimorphic psychotic disorder in a male of 26-year-old, affected by brain palsy, previously with adequate cognitive function, undergoing remarkable confusional fluctuations and a waking state apparently well-preserved. As possible comorbidities or triggers we could count on a tonsillitis and/or a depressive reaction a few days before. Serious consideration must be given to a differential diagnosis with an encephalitis but, despite the presence of an intermittent febricula, it was rejected by both units: internal medicine and neurology, after performing some complementary tests, albeit some more specific tests are still pending. His psychiatric background was also checked, which initially was orientated as a questionable bipolar disorder. At all events, symptoms stopped progressively until, almost complete remittance in the moment he was discharged from the hospital. He recovered his normal functionality. The treatment given was risperidon 2 mL/day, quetiapin 50 mg/8 h and baclofen 10 mg/12 h. This can be used as an example of how many difficulties we usually found to catalogue an acute disorder in first phases, even to encompass the clinical profile within the limits of psychiatry or neurology.