Effects of transcranial electrical stimulation on working memory in patients with schizophrenia: A systematic review and meta-analysis

Treatment of Cognitive Impairment Associated with Schizophrenia Spectrum Disorders: New Evidence, Challenges, and Future Perspectives

Cognitive impairment associated with schizophrenia (CIAS) represents one of the core features of the disorder and has a significant impact on functional and rehabilitation outcomes of people living with schizophrenia spectrum disorders (SSD). The aim of this critical review is to highlight the most recent evidence on effective treatments available for CIAS, to discuss the current challenges in this field, and to present future perspectives that may help to overcome them. Concerning psychopharmacological approaches, among the most indicated strategies for the management and prevention of CIAS is to favor second-generation antipsychotic medications and avoid long-term and high-dose treatments with anticholinergic medications and benzodiazepines. Moreover, non-pharmacological approaches such as cognitive remediation and physical exercise-based programs represent evidence-based interventions in the treatment of CIAS that have shown reliable evidence of effectiveness on both cognitive and functional outcomes. These treatments, however, are still delivered to people accessing mental health services with a diagnosis of CIAS in an uneven manner, even in high-income countries. Academic and clinical partnership and collaboration, as well as advocacy from service users, families, carers, and stakeholders' organizations could help to reduce the bench to bedside gap in the treatment of CIAS. Future perspectives include the development of novel pharmacological agents that could be effective in the treatment of CIAS, the implementation of novel technologies such as telemedicine and virtual reality in the delivery of evidence-based interventions to improve accessibility and engagement, and further research in the field of non-invasive brain stimulation.

Predictors of psychosocial functioning in people diagnosed with schizophrenia spectrum disorders that committed violent offences and in those that did not: Results of the Recoviwel study

Psychosocial functioning represents a core treatment target of Schizophrenia Spectrum Disorders (SSD), and several clinical and cognitive factors contribute to its impairment. However, determinants of psychosocial functioning in people living with SSD that committed violent offences remain to be more thoroughly explored. This study aims to separately assess and compare predictors of psychosocial functioning in people with SSD that did and that did not commit violent offences considering several clinical, cognitive and violence-related parameters. Fifty inmates convicted for violent crimes in a forensic psychiatry setting diagnosed with SSD (OP group) and fifty participants matched for age, gender, education, and diagnosis (Non-OP group) were included in the study. A higher risk of violent relapse as measured by HCR-20 clinical subscale scores (p < 0.002) and greater global clinical severity as measured by CGI-S scores (p = 0.023) emerged as individual predictors of worse psychosocial functioning, as measured by PSP scores, in the OP group. Greater global clinical severity (p < 0.001), worse performance in the processing speed domain as measured by the BACS Symbol Coding (p = 0.002) and TMT-A tests (p = 0.016) and higher levels of non-planning impulsivity as measured by BIS-11 scores (p < 0.001) emerged as individual predictors of worse psychosocial functioning in the Non-OP group. These results confirm that clinical severity impacts psychosocial functioning in all individuals diagnosed with SSD and suggest that while cognitive impairment clearly represents a determinant of worse functional outcomes in most patients, the risk of violent relapse is a specific predictor of worse psychosocial functioning in people with SSD that committed criminal offences.

Repetitive Transcranial Magnetic Stimulation for Working Memory Deficits in Schizophrenia: A Systematic Review of Randomized Controlled Trials

Working memory (WM) deficits are a significant component of neurocognitive impairment in individuals with schizophrenia (SCZ). Two previous meta-analyses, conducted on randomized controlled trials (RCTs), examined the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in addressing WM deficits in individuals diagnosed with SCZ. However, the conclusions drawn from these analyses were inconsistent. Additionally, the commonly used random effects (RE) models might underestimate statistical errors, attributing a significant portion of perceived heterogeneity between studies to variations in study quality. Therefore, this review utilized both RE and quality effects (QE) models to assess relevant RCTs comparing TMS with sham intervention in terms of clinical outcomes. A comprehensive literature search was conducted using PubMed and Scopus databases, resulting in the inclusion of 13 studies for data synthesis. Overall, regardless of whether the RE or QE model was used, eligible RCTs suggested that the TMS and sham groups exhibited comparable therapeutic effects after treatment. The current state of research regarding the use of rTMS as a treatment for WM deficits in patients with SCZ remains in its preliminary phase. Furthermore, concerning the mechanism of action, the activation of brain regions focused on the dorsolateral prefrontal cortex and alterations in gamma oscillations may hold significant relevance in the therapeutic application of rTMS for addressing WM impairments. Finally, we believe that the application of closed-loop neuromodulation may contribute to the optimization of rTMS for WM impairment in patients with SCZ.

Effects of bilateral, bipolar-nonbalanced, frontal transcranial Direct Current Stimulation (tDCS) on negative symptoms and neurocognition in a sample of patients living with schizophrenia: Results of a randomized double-blind sham-controlled trial

Negative symptoms (NS), conceived as Avolition-Apathy (AA) and Expressive Deficit (EXP) domains, and neurocognitive impairments represent unmet therapeutic needs for patients with schizophrenia. The present study investigated if bilateral bipolar-nonbalanced frontal transcranial Direct Current Stimulation (tDCS) could improve these psychopathological dimensions. This randomized, double-blind, sham-controlled study (active-tDCS versus sham-tDCS, both, n = 25) included 50 outpatients diagnosed with schizophrenia clinically stabilized. Patients received 20-min 2 mA active-tDCS or sham-tDCS (anode: left Dorsolateral Prefrontal Cortex; cathode: right orbitofrontal region). Primary outcomes included: PANSS-Negative subscale, Negative Factor (Neg-PANSS), AA and EXP domains; neurocognitive performance at Brief Assessment of Cognition in Schizophrenia. Secondary outcomes included: PANSS subscales and total score, Disorganized/Concrete (DiscC-PANSS) and Positive Factors, Clinical Global Impression (CGI) scores, clinical insight at Scale to Assess Unawareness of Mental Disorder (SUMD). Analysis of covariance (ANCOVA) was performed evaluating between-group changes over time. Significant improvements following active-tDCS were observed for all NS measures (all, p < 0.001; d > 0.8) and for working memory (p = 0.025, d = 0.31). Greater variations following to active treatment emerged also for PANSS-General Psychopathology subscale (p < 0.001; d = 0.54), PANSS total score (p < 0.001; d = 0.69), CGI indexes (all, p < 0.001; d > 0.6), DiscC-PANSS (p < 0.001; d = 0.80) and SUMD-general Unawareness index (p = 0.005; d = 0.15) but not for positive symptoms and others insight measures. Good safety/tolerability profiles were found. Bilateral bipolar-nonbalanced frontal-tDCS is a non-pharmacological approach in schizophrenia effectively improving NS, particularly the AA and EXP domains, probably acting by modulating dysfunctional cortical-subcortical networks. Preliminary results also suggest working memory improvements following tDCS. Further studies are needed to confirm the neurobiological basis of these results.

Cognitive [Computational] Neuroscience Test Reliability and Clinical Applications for Serious Mental Illness (CNTRaCS) Consortium: Progress and Future Directions

The development of treatments for impaired cognition in schizophrenia has been characterized as the most important challenge facing psychiatry at the beginning of the twenty-first century. The Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) project was designed to build on the potential benefits of using tasks and tools from cognitive neuroscience to better understanding and treat cognitive impairments in psychosis. These benefits include: (1) the use of fine-grained tasks that measure discrete cognitive processes; (2) the ability to design tasks that distinguish between specific cognitive domain deficits and poor performance due to generalized deficits resulting from sedation, low motivation, poor test taking skills, etc.; and (3) the ability to link cognitive deficits to specific neural systems, using animal models, neuropsychology, and functional imaging. CNTRICS convened a series of meetings to identify paradigms from cognitive neuroscience that maximize these benefits and identified the steps need for translation into use in clinical populations. The Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia (CNTRaCS) Consortium was developed to help carry out these steps. CNTRaCS consists of investigators at five different sites across the country with diverse expertise relevant to a wide range of the cognitive systems identified as critical as part of CNTRICs. This work reports on the progress and current directions in the evaluation and optimization carried out by CNTRaCS of the tasks identified as part of the original CNTRICs process, as well as subsequent extensions into the Positive Valence systems domain of Research Domain Criteria (RDoC). We also describe the current focus of CNTRaCS, which involves taking a computational psychiatry approach to measuring cognitive and motivational function across the spectrum of psychosis. Specifically, the current iteration of CNTRaCS is using computational modeling to isolate parameters reflecting potentially more specific cognitive and visual processes that may provide greater interpretability in understanding shared and distinct impairments across psychiatric disorders.

Metabolic syndrome in patients with schizophrenia: Why should we care

Metabolic syndrome (MS) is a serious disease in patients with schizophrenia; it is necessary to evaluate the characteristics and influencing factors of MS to provide reliable evidence for the management of schizophrenia. Patients with schizophrenia treated in our hospital from January 1, 2018, to March 31, 2021, were selected. The characteristics and treatment details of MS and no-MS patients were evaluated. Pearson correlation analyses were applied for analyzing MS and related characteristics. Logistic regression analyses were conducted to evaluate the risk factors of MS in patients with schizophrenia. A total of 465 patients with schizophrenia were included, the incidence of MS in patients with schizophrenia was 18.06%. Pearson correlation analyses had found that age (r = 0.621), waist circumference (r = 0.744), body mass index (r = 0.691), diabetes (r = 0.598), course of disease (r = 0.504), triglyceride (r = 0.532), high-density lipoprotein cholesterol (r = -0.518), low-density lipoprotein cholesterol (r = 0.447), and total cholesterol (r = 0.523) were correlated with MS (all P < .05). Logistic regression analyses showed that age ≥55 years (odds ratio [OR]: 2.012, 95% confidence interval [CI]: 1.425-3.196), waist circumference ≥80 cm (OR: 1.944, 95% CI: 1.081-3.172), body mass index ≥24.5 kg/m2 (OR: 2.451, 95% CI: 1.825-3.108), diabetes (OR: 2.301, 95% CI: 1.944-2.881), course of disease ≥15 years (OR: 1.804, 95% CI: 1.236-2.845), triglyceride ≥1.5 mmol/L (OR: 2.032, 95% CI: 1.614-3.079), high-density lipoprotein cholesterol ≤0.8 mmol/L (OR: 1.226, 95% CI: 1.102-1.845), low-density lipoprotein cholesterol ≥2 mmol/L (OR: 1.759, 95% CI: 1.236-1.987), and total cholesterol ≥4.5 mmol/L (OR: 1.664, 95% CI: 1.422-1.852) were the risk factors of MS in patients with schizophrenia (all P < .05). MS is very common in patients with schizophrenia, which may be associated with many possible risk factors, and early interventions and nursing care targeted at those influencing factors are needed to improve the prognosis of schizophrenia.

Effects of transcranial direct current stimulation on brain changes and relation to cognition in patients with schizophrenia: a fMRI study

We studied brain changes during an N-back task before and after 10 sessions of transcranial direct current stimulation (tDCS) and its relation to cognitive changes. This was a double-blind, sham-controlled, randomized study of tDCS in 27 patients with schizophrenia. They performed an N-back task in a 3 T scanner before and after receiving the 10 tDCS sessions. Cognitive performance outside the fMRI session was assessed using the MATRICS Consensus Cognitive Battery and other tests at baseline and several time points after 10 sessions of tDCS. During the N-back task performed during fMRI scans, comparing the 0-back vs. the 2-back task, the active tDCS group demonstrated a significantly increased activation in the right fusiform, left middle frontal, left inferior frontal gyrus (opercular part) and right inferior frontal gyrus (triangular part) and reduced activation in the left posterior cingulum gyrus with most of these results primarily due to increases in activation during the 0-back rather than 2-back task. There were also significant positive or negative correlations between some of the brain changes and cognitive performance. tDCS modulated prefrontal activation at low working memory load or attention mode, but default mode network at higher working memory load. Changes in brain activation measured during the N-back task were correlated with some dimensions of cognitive function immediately after 10 tDCS sessions and at follow-up times. The results support tDCS could offer a potential novel approach for modulating cortical activity and its relation to cognitive function.

European Psychiatric Association guidance on treatment of cognitive impairment in schizophrenia

Background

Although cognitive impairment is a core symptom of schizophrenia related to poorer outcomes in different functional domains, it still remains a major therapeutic challenge. To date, no comprehensive treatment guidelines for cognitive impairment in schizophrenia are implemented.

Methods

The aim of the present guidance paper is to provide a comprehensive meta-review of the current available evidence-based treatments for cognitive impairment in schizophrenia. The guidance is structured into three sections: pharmacological treatment, psychosocial interventions, and somatic treatments.

Results

Based on the reviewed evidence, this European Psychiatric Association guidance recommends an appropriate pharmacological management as a fundamental starting point in the treatment of cognitive impairment in schizophrenia. In particular, second-generation antipsychotics are recommended for their favorable cognitive profile compared to first-generation antipsychotics, although no clear superiority of a single second-generation antipsychotic has currently been found. Anticholinergic and benzodiazepine burdens should be kept to a minimum, considering the negative impact on cognitive functioning. Among psychosocial interventions, cognitive remediation and physical exercise are recommended for the treatment of cognitive impairment in schizophrenia. Noninvasive brain stimulation techniques could be taken into account as add-on therapy.

Conclusions

Overall, there is definitive progress in the field, but further research is needed to develop specific treatments for cognitive impairment in schizophrenia. The dissemination of this guidance paper may promote the development of shared guidelines concerning the treatment of cognitive functions in schizophrenia, with the purpose to improve the quality of care and to achieve recovery in this population.

Transcranial Direct Current Stimulation on the Left Superior Temporal Sulcus Improves Social Cognition in Schizophrenia: An Open-Label Study

BACKGROUND

Patients with schizophrenia show impairments of social cognition, which cause poor real-world functional outcomes. Transcranial direct current stimulation (tDCS) delivered to frontal brain areas has been shown to partially alleviate disturbances of social cognition. In this study, we aimed to determine whether multisession tDCS targeting the superior temporal sulcus (STS), a brain region closely related to social cognition, would improve social cognitive performance in patients with schizophrenia.

METHODS

This was an open-label, single-arm trial to investigate the benefits and safety of multisession tDCS over the left STS. Fifteen patients received tDCS (2 mA × 20 min) two times per day for 5 consecutive days. Anodal and cathodal electrodes were placed over the left STS and right supraorbital regions, respectively. Assessments with the Social Cognition Screening Questionnaire (SCSQ), the Hinting Task (HT), the Brief Assessment of Cognition in Schizophrenia (BACS), and the Positive and Negative Syndrome Scale (PANSS) were conducted at baseline and 1 month after the final stimulation.

RESULTS

Significant improvements were found on theory of mind, as measured using the SCSQ (d = 0.53) and the HT (d = 0.49). These changes on social cognition were not correlated with those of neurocognition, as measured using the BACS or psychotic symptoms, as measured using the PANSS. There were no adverse events of serious/moderate levels attributable to tDCS.

CONCLUSION

These results suggest that administration of multisession tDCS with anode stimulation targeting the left STS provides a novel strategy to improve functional outcomes in patients with schizophrenia.

ETHICS STATEMENT

The National Center of Neurology and Psychiatry Clinical Research Review Board (CRB3180006) approved this study.

TRIAL REGISTRATION

This study was registered within the Japan Registry of Clinical Trials (jRCTs032180026).