Cognitive function was examined in a group of patients with a first-episode schizophrenia spectrum disorder as part of the Early Treatment and Prevention in Psychosis Study. Dr. Opjordsmoen reported the results of 194 patients after the first year of this longitudinal study. These patients had the following types of schizophrenia spectrum disorder: 56 schizophrenia, 44 schizophreniform, 27 schizoaffective disorder, 12 delusions, 22 psychosis not otherwise specified, 8 mood disorders, and 25 affective disorder.

Each participant responded to a battery of tests consisting of eight different neuropsychological tasks, including fingertappng, California verbal learning test, digit span with and without distractor, trail making test, and the visual performance test. Through factor analyses these tests generated seven dimensions of cognitive functioning: working memory, verbal learning, executive functions, impulsivity, perseverations, finger tapping, and backward masking.

Results showed a remarkable degree of stability in all seven cognitive dimensions. No significant differences were found between baseline and one-year follow-up scores on any dimension. When split into subgroups by type of schizophrenia spectrum disorder, a significant improvement was revealed on impulsivity for patients with mood disorder with mood incongruent delusions, vigilance for patients with schizophreniform disorder, and verbal learning for schizoaffective patients.

These results support the conclusion that cognitive impairment is mostly stable in patients with schizophrenia. Dr. Opjordsmoen concluded "These results support the growing body of neurocognitive research suggesting that cognitive deficits are in place by onset of the disorder and change very little thereafter."

Dr. Opjordsmoen discussed the following issues with this study: A comparison group was not included during the first year; subsequent follow-ups will assess a control group. He noted that most patients began the study on neuroleptic medications; many patients changed to novel antipsychotics during the year. Follow-up studies will look for trends regarding type of medication and will also examine whether cognitive deficits remain stable over longer durations.