Cognitive functions and psychopathological symptoms in early-onset schizophrenia

Type and extent of objectively tested cognitive impairments (attention, verbal fluency, nonverbal reasoning) and their association with self-ratings (Paranoia Depression Scale; Frankfurt Complaint Questionnaire) and clinical assessments (Brief Psychiatric Rating Scale, Scales for the Assessment of Positive Symptoms and Negative Symptoms) of psychopathological symptoms were studied in a sample of 74 adolescents primarily suffering from chronic schizophrenia (DSM-III-R; mean duration of illness = 3.4 years), including 15 patients with a very early onset (< 14 years). Special consideration was given to the differentiation between positive and negative symptoms. In cross-sectional analyses, the schizophrenic adolescents were remarkably impaired in both cognitive functions (attention, reasoning) and psychopathological measures (BPRS, SANS, SAPS). However, factor analysis yielded orthogonal factors for cognitive and psychopathological parameters, and canonical correlation analyses did not find a significant correlation between these two areas. As the degree of objectively measured cognitive impairment in chronic schizophrenic adolescents cannot be predicted by the severity of individual psychopathological symptoms, a multidimensional evaluation of the symptomatology seems to be appropriate. Moreover, premorbid disturbances (motor and/or language developmental disorders) and onset characteristics (age, pattern, subdiagnosis), and their relationship to cognitive impairments were investigated. Premorbid disturbances were confirmed as risk factors for the subsequent occurrence of cognitive impairments.