A narrative review of treatment interventions to improve cognitive performance in schizophrenia, with an emphasis on at-risk and early course stages

The effect of physical exercise on cognitive function in schizophrenia patients: A GRADE assessed systematic review and meta-analysis of controlled clinical trials

BACKGROUND

Physical exercise has demonstrated the potential to improve cognitive impairment in schizophrenia, although the results are limited. The objective of this meta-analysis is to synthesize the existing evidence on the impact of physical exercise on cognitive functions in schizophrenia.

METHODS

A systematic search of PubMed, Scopus, Web of Science, and Embase was conducted. The study included controlled clinical trials on patients with schizophrenia that received physical exercise as the intervention for improving cognition. A meta-analysis was conducted using a random-effects model, and the outcomes were reported using the standardized mean difference (SMD) and a 95 % confidence interval (95 % CI).

RESULTS

A total of 22 articles, including 1066 patients (565 in the intervention group and 501 in the control group), were included in the final analysis. Physical exercises significantly improved global cognition (SMD: 0.73, 95 % CI (0.46-1.00), P < 0.001), and aerobic exercise was found to have a more significant effect than resistance and mindfulness exercise (SMD: 0.76, 95 % CI (0.45-1.07), P < 0.001). The speed of processing [SMD: 0.88, 95 % CI (0.37-1.38), P = 0.001], attention [SMD: 0.61, 95 % CI (0.20-1.02), P = 0.004], and visual learning memory [SMD: 1.42, 95 % CI (0.14-2.71), P = 0.03] demonstrated significant improvement after physical exercise, while no significant effects were observed on working memory, verbal learning memory, reasoning and problem-solving, and social cognition.

CONCLUSIONS

Exercise can improve overall cognitive function in people with Schizophrenia. However, it is unclear whether this improvement is significant in specific cognitive domains.

Reduced slow wave density is associated with worse positive symptoms in clinical high risk: An objective readout of symptom severity for early treatment interventions?

Individuals at clinical high risk for psychosis (CHR) present subsyndromal psychotic symptoms that can escalate and lead to the transition to a diagnosable psychotic disorder. Identifying biological parameters that are sensitive to these symptoms can therefore help objectively assess their severity and guide early interventions in CHR. Reduced slow wave oscillations (∼1 Hz) during non-rapid eye movement sleep were recently observed in first-episode psychosis patients and were linked to the intensity of their positive symptoms. Here, we collected overnight high-density EEG recordings from 37 CHR and 32 healthy control (HC) subjects and compared slow wave (SW) activity and other SW parameters (i.e., density and negative peak amplitude) between groups. We also assessed the relationships between clinical symptoms and SW parameters in CHR. While comparisons between HC and the entire CHR group showed no SW differences, CHR individuals with higher positive symptom severity (N = 18) demonstrated a reduction in SW density in an EEG cluster involving bilateral prefrontal, parietal, and right occipital regions compared to matched HC individuals. Furthermore, we observed a negative correlation between SW density and positive symptoms across CHR individuals, suggesting a potential target for early treatment interventions.