The Effects of Hypertension and Body Mass Index on Cognition in Schizophrenia

Objective: In recent years there has been a greater appreciation of the elevated prevalence of cardiovascular risk factors in the schizophrenia population and the liability some treatments have for their development. These vascular risk factors are in turn important risk factors in the development of dementia and more subtle cognitive impairments. However, their impact on the cognitive functions of patients with schizophrenia remains underexplored. The authors investigated whether vascular risk factors influence the cognitive impairments of schizophrenia and whether their effects on cognition in schizophrenia are different from those observed in nonpsychiatric comparison subjects. Method: The authors compared 100 patients with schizophrenia and 53 comparison subjects on cognitive test performance in 2x2 matrices composed of in-dividual vascular risk factors and group (schizophrenia patients and comparison subjects). Results: Hypertension exerted a significant negative effect on immediate delayed and recognition memory in both groups. Patients with schizophrenia and hypertension were adversely affected in recognition memory, whereas comparison subjects were not. A body mass index above 25 was associated with negative effects on delayed memory in both groups, although the association fell short of statistical significance. Conclusions: Given that patients with schizophrenia have a higher prevalence of vascular risk factors than the general population and are undertreated for them, treatment of these risk factors may significantly improve cognitive outcome in schizophrenia.