The role of the blood-brain barrier in psychiatric disorders

Abstract

The blood-brain barrier (BBB) is formed by continuous, closely connected endothelial cells, enveloped in the basal lamina, pericytes, and foot extensions of astrocytes. BBB has a vital role in brain metabolism and protects the brain parenchyma from harmful agents present in the systemic circulation. Damage to the BBB and an increase in its permeability have an important role in many neurodegenerative diseases. This paper aims to review the literature on the impact of the BBB damage on psychiatric illness, a largely neglected and under researched area. Links between BBB impairment and specific neuropsychiatric disorders are described including schizophrenia, affective disorders, dementias with behavioral disorders, and alcohol use disorder, with comparison to typical hereditary small vessel diseases affecting the BBB such as cerebral autosomal dominant arteriopathy with subcortical infarction and leukoencephalopathy (CADASIL) and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). The authors critically summarize possible pathogenic mechanisms linking BBB damage and these common disorders.