Cognitive Impairments in Schizophrenia and their Relationship to Risk Factors and Clinical Characteristics of the Illness
Year: 2013
Type: article
Study design: Observational Study
Abstract: Schizophrenia is considered to be a neurodevelopmental disorder.Although the aetiology of schizophrenia remains largely unknown, it appears to result from several factors, including genetic vulnerability and environmental insults as well as their interactions.Schizophrenia is usually associated with broad cognitive impairment and related problems in psychosocial functioning.As in patients with schizophrenia, patients with schizoaffective disorder, a psychiatric disorder characterized by both symptoms of schizophrenia and prominent affective symptoms, also show cognitive impairment.Previous research has identified many risk factors for schizophrenia, such as obstetric complications and male sex.In addition, in Finland, internal genetic isolates with a high prevalence of schizophrenia have been identified.However, few studies have investigated the relationship between these risk factors for schizophrenia and cognitive functioning. Cognitive Impairment in Schizophreniaexecutive functions, attention, working memory, verbal learning and memory and verbal ability.The schizophrenia group demonstrated broad cognitive impairment compared to the control group with large effect sizes.In schizoaffective disorder, broad cognitive impairment with effect sizes ranging from medium to large were detected.Differences in clinical characteristics accounted for the differences in cognitive functioning between the diagnostic groups.Irrespective of diagnosis, patients with severe negative symptoms and a high dose of antipsychotic medication had the most severe cognitive impairment.Both low and high birth weight were associated with more severe cognitive impairment than intermediate birth weight in persons with schizophrenia and their first-degree relatives.Sex differences in cognitive functions were mostly preserved in schizophrenia families when compared to controls despite large cognitive impairment in schizophrenia, and mild cognitive impairment in firstdegree relatives.In persons with schizophrenia and their first-degree relatives, persons from the internal isolate had slightly better performance in some of the cognitive measures than persons from the rest of the country.However, no such differences were noticed in the controls.In conclusion, persons with schizoaffective disorder demonstrated broad cognitive impairment, which was milder than in schizophrenia.The results suggest that symptom severity predicts the level of cognitive impairment in these disorders more accurately than categorical diagnosis does.The results also showed that the assessed schizophrenia risk factors may have distinct associations with cognitive functioning.Low and high birth weight were associated with slightly lower cognitive performance than intermediate birth weight in persons with schizophrenia and in their first-degree relatives.Despite sex differences in illness characteristics, sex did not affect the level of cognitive impairment in persons with schizophrenia or in their first-degree relatives.Originating from an internal isolate was associated with slightly higher cognitive performance than originating from the rest of Finland both in persons with schizophrenia and in their first-degree relatives, but not in the control group.This difference may reflect differences in the genetic aetiology of schizophrenia between the isolate and the rest of Finland.
Author: Minna Torniainen
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1244566872