Chronic traumatic encephalopathy (CTE) is a neurodegenerative condition characterized by the perivascular deposition of phosphorylated τ (p-τ) protein aggregates resulting from repetitive mild traumatic brain injury (rTBI). Advances in the field have revealed the significance of repetitive head trauma in the pathogenesis of CTE in contact sports as well as military veterans. In this study we provide evidence of blood-brain barrier (BBB) disruption in regions of intense perivascular p-τ deposition in a former professional boxer diagnosed with CTE and schizophrenia. P-τ deposition was associated with loss of the tight junction protein claudin-5 and enhanced extravasation of endogenous blood components such as fibrinogen and IgG. We also provide evidence of tight junction disruption in individuals with schizophrenia, with discontinuous claudin-5 immunoreactivity in the parietal cortex. This data highlights a common phenotype of a dysfunctional BBB in individuals with CTE and schizophrenia and may represent a novel correlate of neural dysfunction in individuals at risk of developing CTE and schizophrenia. .