Cognitive phenotype and psychiatric disorder in 22q11.2 deletion syndrome: A review

The behavioural phenotype of 22q11.2 deletion syndrome syndrome (22q11DS), one of the most common human multiple anomaly syndromes, frequently includes intellectual disability (ID) together with high risk of diagnosis of psychotic disorders including schizophrenia. Candidate cognitive endophenotypes include problems with retrieval of contextual information from memory and in executive control and focussing of attention. 22q11DS may offer a model of the relationship between ID and risk of psychiatric disorder. This paper reviews research on the relationship between the cognitive phenotype and the development of psychiatric disorders in 22q11DS. Aspects of cognitive function including verbal I.Q., visual memory, and executive function, are associated with mental health outcome in people with 22q11DS. This relationship may result from a common neurobiological basis for the cognitive difficulties and psychiatric disorders. Some of the cognitive difficulties experienced by people with 22q11DS, especially in attention, memory retrieval, and face processing, may, however, in themselves constitute risk factors for development of hallucinations and paranoid delusions. Future research into factors leading to psychiatric disorder in people with 22q11DS should include assessment of social and psychological factors including life events, symptoms associated with trauma, attachment, and self-esteem, which together with cognitive risk factors may mediate mental health outcome.