Predictors and longitudinal course of cognitive functioning in schizophrenia spectrum disorders, 10 years after baseline: The OPUS study

BACKGROUND: Identifying baseline predictors of the long-term course of cognitive functioning in schizophrenia spectrum disorders is important because of associations between cognitive functioning (CF) and functional outcome. Determining whether CF remains stable or change during the course of illness is another matter of interest.

METHODS: Participants from The Danish OPUS Trial, aged 18-45years, with a baseline ICD-10 schizophrenia spectrum diagnosis, were assessed on psychopathology, social and vocational functioning at baseline, and cognitive functioning 5 (N=298) and 10years (N=322) after baseline. Uni- and multi-variable regression analyses of potential baseline predictors of 10-year CF were performed. Also, changes in CF and symptomatology between 5 and 10years of follow-up were assessed.

FINDINGS: Baseline predictors of impaired CF after 10years included male gender, unemployment, poor premorbid achievement and later age of onset. Having finished high school and receiving early intervention treatment was associated with better CF. Age, growing up with both parents, number of family and friends, primary caregivers education, premorbid social function, negative symptoms, GAF (symptoms, function) and substance abuse, were associated with CF in univariable analyses. Non-participants generally suffered from more severe dysfunction. Longitudinally, amelioration in negative symptoms was associated with improved speed of processing and executive functions. Symptom scores generally improved with time, while scores for all cognitive tests remained stable.

CONCLUSION: The current study identifies several robust associations between baseline characteristics and 10-year cognitive outcome. Several other variables were univariably associated with 10-year cognitive outcome. Also, we found evidence for stability of CF over time.