Cognitive decline in 22q11.2DS

A publication from the International Consortium on Brain and Behavior in 22q11.2 Deletion Syndrome

Comment on:

Cognitive decline preceding the onset of psychosis in patients with 22q11.2 deletion syndrome.

Vorstman et al. (2015) JAMA Psychiatry, 72(4):377-85.

Patients with 22q11.2 deletion syndrome (22q11.2DS) have an elevated (25%) risk of developing schizophrenia. Recent reports have suggested that a subgroup of children with 22q11.2DS display a substantial decline in cognitive abilities starting at a young age. The International Consortium on Brain and Behavior in 22q11.2 Deletion Syndrome set out to determine whether early cognitive decline is associated with risk of psychotic disorder in 22q11.2DS. Among 411 patients with 22q11.2DS in this study, 55 (13.4%) were diagnosed as having a psychotic disorder. The mean full-scale IQ at first cognitive assessment was lower in patients who developed a psychotic disorder compared with those without a psychotic disorder. In those who developed psychotic illness, the decline in full-scale IQ was significantly steeper (P < .001). The divergence of verbal IQ trajectories between those who subsequently developed a psychotic disorder and those who did not was distinguishable from age 11 years onward. The authors concluded that in 22q11.2DS, early cognitive decline is a robust indicator of the risk of developing a psychotic illness. These findings mirror those observed in idiopathic schizophrenia. The results also provide further support for investigations of 22q11.2DS as a genetic model for elucidating neurobiological mechanisms underlying the development of psychosis.