Recent developments in understanding the relationship between 22q11.2 deletion syndrome and psychosis.

PURPOSE OF REVIEW: Individuals with 22q11.2 deletion syndrome have high rates of comorbid mental illness, particularly psychosis and schizophrenia. The purpose of this review is to summarize recent research in the area of 22q11.2 deletion syndrome and psychosis.

RECENT FINDINGS: Research over the past year has identified negative symptoms, functional impairment, dysphoric mood and a childhood diagnosis of attention deficit hyperactivity disorder as important clinical predictors of psychosis risk in 22q11.2 deletion syndrome. As previously reported in nondeleted schizophrenia, recent studies have implicated neuroinflammation as a possible neurobiological mechanism for psychosis in 22q11.2 deletion syndrome. Recent neuroimaging findings suggest that the cortex is significantly thinner in those with 22q11.2 deletion syndrome and psychosis compared to those without psychosis, replicating similar findings in nondeleted schizophrenia. Further data from the International 22q11.2 Deletion Syndrome Brain and Behavior Consortium have suggested that chromosomal microdeletions are significantly more likely to involve protein-coding genes and several rare copy number variants are associated with the presence of psychosis in deleted individuals.

SUMMARY: There have been several significant recent advances to further characterize the high rates of psychosis in 22q11.2 deletion syndrome, to identify additional clinical predictors of psychosis and to increase our understanding of the neural substrate and genetic aetiology of psychosis in 22q11.2 deletion syndrome.