Relationships of Age at Onset With Clinical Features and Cognitive Functions in a Sample of Schizophrenia Patients

Background: A number of studies investigated the relationships of age at onset with clinical presentation and cognitive performance of schizophrenic patients. The aim of the present study was to assess demographic and clinical characteristics; psychopathologic, social functioning, and quality-of-life ratings; and neuropsychological measures in a sample of patients with stabilized schizophrenia and to identify which factors independently contributed to a multiple regression model with age at onset as the dependent variable.

Method: Ninety-six consecutive outpatients with schizophrenia (DSM-IV-TR criteria) were included in the study. Assessment instruments were as follows: a semistructured interview, the Clinical Global Impressions scale, the Comprehensive Psychopathological Rating Scale, and the Positive and Negative Syndrome Scale (PANSS) for psychopathology of schizophrenia; the Calgary Depression Scale for Schizophrenia (CDSS) for depression; the Social and Occupational Functioning Assessment Scale and the Sheehan Disability Scale for social functioning; the Quality of Life Scale; and a neuropsychological battery including the Wisconsin Card Sorting Test (WCST) and the Continuous Performance Test. Two models of multiple regression were tested: the first included clinical features and psychopathologic, social functioning, and quality-of-life scales; the second also considered neuropsychological variables. Data were collected from October 2001 to November 2002.

Results: The first multiple regression showed that age at onset was significantly related to scores on the PANSS subscale for negative symptoms (p = .042) and the CDSS (p = .041); the second regression found a relation of age at onset with PANSS score for negative symptoms (p = .002) and 2 neuropsychological measures, number of perseverative errors on the WCST and Continuous Performance Test reaction time (p = .0005 for both).

Conclusion: Our data indicate that, when results of neuropsychological tests are considered, early age at onset of schizophrenia is associated with severity of negative symptoms and compromised cognitive measures of executive functioning and sustained attention.