Can neuropsychological profile (RBANS) predict co-morbid traumatic brain injury and psychosis?

Background: Traumatic insanity has been acknowledged since Meyer (1904), yet the relationship between traumatic brain injury (TBI) and psychosis remains poorly understood and relatively under-researched. To date, systematic and standardised neuropsychological research of psychosis following traumatic brain injury (PFTBI) has not been reported, with work relying on retrospective chart reviews, case studies, and loosely defined self-reported TBI. This is likely due to the difficulties associated with recruiting and assessing PFTBI cohorts given the severity of their illness. We aimed to conduct a standardised empirical investigation into the cognitive/ neuropsychological profile of PFTBI, and determine if dual diagnosis can be predicted by scores. Methods: The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was given to four groups; PFTBI (N=10), TBI (N=10), schizophrenia (N=23), and healthy controls (N=23). TBI was confirmed by patient records (or a first degree relative where no records were available). Psychosis was determined by a SCID interview and current symptoms were obtained using the PANNS. Participants were matched as closely as possible across demographic and injury related variables; importantly, no significant differences pertaining to injury were shown between the PFTBI and TBI groups with the exception of time since injury (TBI; M=9.80 yrs [SD=9.35], PFTBI; M=24.80 yrs [SD=10.89], t(18)=3.30, p=0.004, d=-1.56), and induced coma (TBI; 70%, PFTB;10%