Cognitive decline following psychosis onset: data from the PACE clinic

The origin of cognitive impairments in psychotic disorders is still unclear. Although some deficits are apparent prior to the onset of frank illness, it is unknown if they progress.

To investigate whether cognitive function declined over the transition to psychosis in a group of ultra-high risk individuals.

Participants consisted of two groups: controls (n=17) and individuals at ultra-high risk for development of psychosis (n=16). Seven of the latter group later developed psychosis. Neuropsychological testing was conducted at baseline and again after at least a 12-month interval.

Both the Visual Reproduction sub-test of the Wechsler Memory Scale-Revised and Trail-Making Test B showed a decline over the follow-up period that was specific to the group who became psychotic. In addition, both high-risk groups showed a decline in digit span performance. No other task showed significant change over time.

These preliminary data suggest that as psychosis develops there may be a specific decline in visual memory and attentional set-shifting, reflecting impairments in efficient organisation of visual stimuli. This may be caused by either the illness itself or treatment with antipsychotic medication.