INFORMACIONES PSIQUIÁTRICAS 246

Informaciones Psiquiátricas 2022 - n.º 246 19 1.7% to 9.08%. Achte et al 26 studied 3552 wounded soldiers, 42% with open head trau- ma and 30% with post-traumatic epilepsy, with a very long follow-up period: 22 to 26 years. They report the highest prevalence of a large sample with TBI: 317 cases (8,9%). The long follow-up period, the compensa- tion associated to the diagnosis, the lack of temporal limitation between trauma and onset of psychosis (42% of the psychosis started 10 years later) and the imprecise use of the concept of psychosis (Korsakoff syndrome, dementia and confusion were in- cluded) help to explain the very high pre- valence. The most recent large sample was collected in Belgium 27,28 : retrospective study of 530 patients with TBI with 18 psychosis being diagnosed, 3,4% of the sample. Most cases started soon after the trauma, 80% within a 6 month period. It is likely that a number of postraumatic confusional cases were included. When all the samples are pondered, and post-traumatic confusional states excluded, it can be estimated that the prevalence of psychosis after traumatic brain injury ranges from 2 to 3% 29 . Unlike cognitive disorder, there is no need for a close temporal link between brain trauma and onset of psycho- sis. Some of the psychotic episodes appear soon after the injury while others do years after. Auditory hallucinations and delusional ideas are the most common symptoms with depressive symptomatology playing a rele- vant prodromal or comorbid role. Severity of trauma and temporal localization are impor- tant risk factors, though cases with mild TBI have also been reported. Misidentification on syndromes after bra- in injury tend to be linked to right brain lesions, independent of the etiology. Right sided strokes present a number of psychotic syndromes related to body awareness: denial of ownership of the arm or leg, the belief that there are supernumerary limbs or soma- toparaphrenia, the belief that a part of the body, usually the left arm, belongs to so- mebody else. Capgras syndrome, Fregoli syn- drome and reduplicative paramnesia tend to appear after abnormalities in the experience of familiarity, commonly associated with right brain lesions. Other mental symptoms that need to be differentiated from psychosis are confabu- lations and false memories. Confabulations are traditionally linked to Korsakoff syndro- me following Wernicke´s encephalopathy, but a number of patients with severe TBI or stroke can also present these symptoms. Other forms of false memories or difficulties categorizing mental contents are sometimes referred by patients with ABI: the bounda- ries between the memory of a dream, an imagination or a real fact are not always clear to patients. THE NEUROPSYCHIATRY OF ACQUIRED BRAIN INJURY