Cognitive impairment in people with schizophrenia: an umbrella review

Abstract

Cognitive impairment is one of the core symptoms of schizophrenia. Quite a number of systematic reviews were published related to cognitive impairment in people with schizophrenia (PWS). This umbrella review, therefore, aimed at reviewing and synthesizing the findings of systematic reviews related to domains of cognition impaired and associated factors in PWS. We searched four electronic databases. Data related to domains, occurrence, and associated factors of cognitive impairment in PWS were extracted. The quality of all eligible systematic reviews was assessed using A MeaSurement Tool to Assess methodological quality of systematic Review (AMSTAR) tool. Results are summarized and presented in a narrative form. We identified 63 systematic reviews fulfilling the eligibility criteria. The included reviews showed that PWS had lower cognitive functioning compared to both healthy controls and people with affective disorders. Similar findings were reported among psychotropic free cases and people with first episode psychosis. Greater impairment of cognition was reported in processing speed, verbal memory, and working memory domains. Greater cognitive impairment was reported to be associated with worse functionality and poor insight. Cognitive impairment was also reported to be associated with childhood trauma and aggressive behaviour. According to our quality assessment, the majority of the reviews had moderate quality. We were able to find a good number of systematic reviews on cognitive impairment in PWS. The reviews showed that PWS had higher impairment in different cognitive domains compared to healthy controls and people with affective disorders. Impairment in domains of memory and processing speed were reported frequently.

Predictors of everyday functional impairment in older patients with schizophrenia: A cross-sectional study

“…Therefore, this study aimed to explore the association between everyday functional capacity and current comorbidity in physical and mental conditions in elderly patients with schizophrenia. In line with previous studies, we hypothesized that the decline in functional activity in elderly patients with schizophrenia is associated with cognitive impairment (15). Second, risk factors of dysfunction in everyday instrumental activities were influenced by many physical and mental conditions, building a comprehensive predictive model involving diseases classified by the eight systems of the human body and other clinical outcomes.…”

Efficacy of auricular plaster therapy for sleep disorders in preschool children with autism spectrum disorders: Study protocol for a randomized controlled trial

“…Participants who meet any of the following criteria will be excluded: (1) known severe cardiovascular, cerebrovascular, liver, kidney, blood, and other systemic diseases; (2) known history of Asperger's syndrome, Heller syndrome, Rett syndrome, specific receptive language disorder, or childhood schizophrenia before ( 53 – 55 ); (3) known taking part in other clinical trials.…”

Baseline global brain structural and functional alterations at the time of symptom onset can predict subsequent cognitive deterioration in drug-naïve first-episode schizophrenia patients: Evidence from a follow-up study

“…However, identifying cognitive impairments that precede the onset of illness is arduous, because cognitive deficits at the early stages of disease are subtle, but become increasingly pronounced as the patient's progress from the prodromal phase to the first episode of psychotic symptoms (28)(29)(30). The rate at which patients show cognitive deterioration has been shown to differ among schizophrenia patients from the first episode of psychotic symptoms, experiencing mild to severe cognition impairment, especially over the first two years of antipsychotic treatment, even with adequate dosage and duration (27,(31)(32)(33)(34)(35)(36).…”

“…Cognitive impairment refers to deficits in the neurocognitive domains, including complex attention, executive function, learning, and memory, language, perceptual-motor, and social cognition (36,41,42). Based on neurodevelopment hypothesis of schizophrenia, cognitive impairment can be viewed as a reflection of the brain's functional and structural abnormalities, especially within the brain circuits involved in information processing (43)(44)(45).…”

“…Based on neurodevelopment hypothesis of schizophrenia, cognitive impairment can be viewed as a reflection of the brain's functional and structural abnormalities, especially within the brain circuits involved in information processing (43)(44)(45). Many neuroimaging studies support the notion that brain gray matter volume (GMV) abnormalities and brain functional connectivity density (FCD) disturbances in the whole brain can be the neural basis of cognitive impairments (18,24,25,(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(46)(47)(48)(49)(50)(51)(52)(53)(54). However, until now, few studies have reported the relationship between the baseline global brain gray matter volume (gGMV) and global functional connectivity density (gFCD) and the subsequent cognitive deterioration in drug-naïve first-episode patients with schizophrenia following a two-year antipsychotic treatment with adequate dosages and adherence.…”