Grant: Fellowship PA: Mach-Gaensslen Found. -Mental Health, Addictions/Cognitive Health

Social marginalization is an important risk factor for poor health and is associated with psychotic and substance use disorders, traumatic brain injury (TBI), HIV and hepatitis C infection. Many substances used by marginalized people cause brief episodes of substance-induced psychosis (SIP). SIP is associated with increased risk of mortality and functional impairment, yet we do not fully understand whether antipsychotic treatment is effective in mitigating it. Substance use also changes how the brain functions and may result in cognitive impairment (CI), which is frequently found in homeless individuals. This study aims to assess to what extent individuals with prior brain insults, such as TBIs, who also use substances are at increased risk of cognitive impairment or of SIP compared to those without brain insults. We also aim to determine whether certain types of cognitive problems are associated with increased susceptibility to SIP and if using antipsychotic medications can decrease the frequency and severity of- as well as health resources used in SIP. This study will use data from the Hotel Study, an ongoing longitudinal community-based study in Vancouver's Downtown Eastside. This neighbourhood consists of residents suffering from severe poverty, mental/physical illness, and addiction. The Hotel Study was designed to better characterize biological, psychological and social factors affecting health of marginalized individuals. Participants underwent comprehensive assessments at study entry as well as monthly follow-up assessments looking at their prescription and non-prescription substance use, symptoms of psychosis and participated in annual assessments of their cognition along with brain imaging. Statistical modelling will be used to help address study objectives. Having such information could help better guide clinicians in engaging and treating this vulnerable patient population and prevent chronic disability.