Progress and Pitfalls in Developing Agents to Treat Neurocognitive Deficits Associated with Schizophrenia

Effect of the Part-to-Whole Program on Functional Remission in Schizophrenia: A Randomized Controlled Community Mental Health Study

PURPOSE

To assess the influence of the Part-to-Whole Program on functional remission levels in individuals with schizophrenia enrolled at a community mental health center (CMHC).

METHOD

Sixty individuals receiving follow up and treatment at two CMHCs were randomly allocated to intervention and control groups. The Part-to-Whole Program was implemented in the intervention group over a 5-week period. The program's efficacy was assessed using the Functional Remission of General Schizophrenia Scale (FROGS).

RESULTS

Posttest scores of the intervention group in the FROGS sub-dimensions (social functioning, health and treatment, daily life, and occupational functioning) were found to be considerably higher than those in the control group (p < 0.05).

CONCLUSION

The Part-to-Whole Program, led by nurses in CMHCs, is an effective and feasible intervention that improves social functioning, health and treatment, daily life, and occupational functioning of individuals with schizophrenia. [Journal of Psychosocial Nursing and Mental Health Services, xx(x), xx-xx.].

Quantitative Systems Pharmacology Development and Application in Neuroscience

Successful clinical development of therapeutics in neurology and psychiatry is challenging due to the complexity of the brain, the lack of validated surrogate markers and the nature of clinical assessments. On the other hand, tremendous advances have been made in unraveling the neurophysiology of the human brain thanks to technical developments in noninvasive biomarkers in both healthy and pathological conditions.Quantitative systems pharmacology (QSP) aims to integrate this increasing knowledge into a mechanistic model of key biological processes that drive clinical phenotypes with the objective to support research and development of successful therapies. This chapter describes both modeling of molecular pathways resulting in measurable biomarker changes, similar to modeling in other indications, as well as extrapolating in a mechanistic way these biomarker outcomes to predict changes in relevant functional clinical scales.Simulating the effect of therapeutic interventions on clinical scales uses the modeling methodology of computational neurosciences, which is based on the premise that human behavior is driven by firing activity of specific neuronal networks. While driven by pathology, the clinical behavior can also be influenced by various medications and common genotype variants. To address this occurrence, computational neuropharmacology QSP models can be developed and, in principle, applied as virtual twins, which are in silico clones of real patients.Overall, central nervous system (CNS) QSP is an important additional tool for supporting research and development from the preclinical stage to post-marketing studies and clinical practice. Overall, CNS QSP is an important additional tool for supporting research and development from the preclinical stage to post-marketing studies and clinical practice.

Advances in the Treatment of Cognitive Impairment in Schizophrenia: Targeting NMDA Receptor Pathways

Cognitive impairment is a core feature of schizophrenia, playing a pivotal role in the pathogenesis and prognosis of this disorder. Cognitive impairment in schizophrenia encompasses a wide range of domains, including processing speed, episodic memory, working memory, and executive function. These deficits persist throughout the course of the illness and significantly impact functional outcomes and quality of life. Therefore, it is imperative to identify the biological basis of cognitive deficits in schizophrenia and develop effective treatments. The role of N-methyl-D-aspartate (NMDA) receptors in synaptic transmission and plasticity has long been recognized, making them potential targets for schizophrenia treatment. This review will focus on emerging pharmacology targeting NMDA receptors, offering strategies for the prevention and treatment of cognitive deficits in schizophrenia.

Conceptualization and characterization of "primary" and "secondary" cognitive impairment in schizophrenia

Cognitive impairment represents one of the core features of schizophrenia, involves both neurocognition and social cognition domains, and has a significant negative impact on real-world functioning. The present review provides a framework for the conceptualization and characterization of "primary" and "secondary" cognitive impairment in schizophrenia. In this conceptualization, primary cognitive impairment can be defined as a consequence of the neurobiological alterations that underlie psychopathological manifestations of the disorder, while secondary cognitive impairment can be defined as the results of a source issue that has a negative impact on cognitive performance. Sources of secondary cognitive impairment are frequent in people with schizophrenia and include several different factors, such as positive and negative symptoms, depressive symptoms, autistic symptoms, pharmacotherapy, substance abuse, metabolic syndrome, social deprivation, and sleep disorders. It can be hypothesized that secondary cognitive impairment may be improved by effectively resolving the source issue, while primary cognitive impairment may benefit from dedicated treatment. Further research is required to confirm this hypothesis, to better characterize the distinction between primary and secondary cognitive impairment in a clinical and in a neurobiological perspective, and to evaluate the impact of systematically assessing and treating secondary cognitive impairment.

Definition, assessment and treatment of cognitive impairment associated with schizophrenia: expert opinion and practical recommendations

A considerable proportion of patients with schizophrenia perform below population norms on standardized neuropsychological tests, and the performance of those performing within normal range is lower than predicted based on parental education. Cognitive impairment predates the onset of psychosis, is observed during symptom remission and in non-affected first-degree relatives of patients. At the present time, cognitive deficits are regarded as key features of schizophrenia, important determinants of poor psychosocial outcome and targets for both pharmacological and non-pharmacological treatment strategies. A group of eight key opinion leaders reviewed and discussed latest advances in scientific research and current good clinical practices on assessment, management, and treatment of CIAS. In the present paper they summarize the current evidence, identify main gaps between current knowledge and mental health services clinical practice, and provide practical recommendations to reduce the gap.

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.

Pharmacological Treatment of Cognitive Impairment Associated With Schizophrenia: State of the Art and Future Perspectives

Cognitive Impairment Associated with Schizophrenia (CIAS) represents one of the core dimensions of Schizophrenia Spectrum Disorders (SSD), with an important negative impact on real-world functional outcomes of people living with SSD. Treatment of CIAS represents a therapeutic goal of considerable importance, and while cognition-oriented evidence-based psychosocial interventions are available, effective pharmacological treatment could represent a game-changer in the lives of people with SSD. The present critical review reports and discusses the evidence regarding the effects of several pharmacological agents that are available in clinical practice or are under study, commenting on both current and future perspectives of CIAS treatment. In particular, the effects on CIAS of antipsychotic medications, anticholinergic medications, benzodiazepines, which are currently commonly used in the treatment of SSD, and of iclepertin, d-serine, luvadaxistat, xanomeline-trospium, ulotaront, anti-inflammatory molecules, and oxytocin, which are undergoing regulatory trials or can be considered as experimental agents, will be reported and discussed. Currently, available pharmacological agents do not appear to provide substantial benefits on CIAS, but accurate management of antipsychotic medications and avoiding treatments that can further exacerbate CIAS represent important strategies. Some molecules that are currently being investigated in Phase 2 and Phase 3 trials have provided very promising preliminary results, but more information is currently required to assess their effectiveness in real-world contexts and to provide clear recommendations regarding their use in clinical practice. The results of ongoing and future studies will reveal whether any of these molecules represents the awaited pharmacological game-changer in the treatment of CIAS.

N-Acetylcysteine and a Specialized Preventive Intervention for Individuals at High Risk for Psychosis: A Randomized Double-Blind Multicenter Trial

Background and Hypothesis

Clinical high risk for psychosis (CHR-P) offers a window of opportunity for early intervention and recent trials have shown promising results for the use of N-acetylcysteine (NAC) in schizophrenia. Moreover, integrated preventive psychological intervention (IPPI), applies social-cognitive remediation to aid in preventing the transition to the psychosis of CHR-P patients.

Study Design

In this double-blind, randomized, controlled multicenter trial, a 2 × 2 factorial design was applied to investigate the effects of NAC compared to placebo (PLC) and IPPI compared to psychological stress management (PSM). The primary endpoint was the transition to psychosis or deterioration of CHR-P symptoms after 18 months.

Study Results

While insufficient recruitment led to early trial termination, a total of 48 participants were included in the study. Patients receiving NAC showed numerically higher estimates of event-free survival probability (IPPI + NAC: 72.7 ± 13.4%, PSM + NAC: 72.7 ± 13.4%) as compared to patients receiving PLC (IPPI + PLC: 56.1 ± 15.3%, PSM + PLC: 39.0 ± 17.4%). However, a log-rank chi-square test in Kaplan-Meier analysis revealed no significant difference of survival probability for NAC vs control (point hazard ratio: 0.879, 95% CI 0.281-2.756) or IPPI vs control (point hazard ratio: 0.827, 95% CI 0.295-2.314). The number of adverse events (AE) did not differ significantly between the four groups.

Conclusions

The superiority of NAC or IPPI in preventing psychosis in patients with CHR-P compared to controls could not be statistically validated in this trial. However, results indicate a consistent pattern that warrants further testing of NAC as a promising and well-tolerated intervention for CHR patients in future trials with adequate statistical power.

Low-dose lithium mono- and adjunctive therapies improve MK-801-induced cognitive impairment and schizophrenia-like behavior in mice - Evidence from altered prefrontal lobe Ca2+ activity

BACKGROUND

Few studies have evaluated lithium either as monotherapy or in combination with anti-psychotic agents to improve cognition in murine models of schizophrenia.

METHODS

Visualization of Ca²⁺ activity in the prefrontal cortex was used to characterize brain neural activity. Novel object recognition (NOR), Morris water maze (MWM), and fear conditioning (FCT) tests were used to characterize cognitive performance; while pre-pulse inhibition (PPI), elevated plus maze (EPM) and the open field test (OFT) were used to characterize schizophrenia-like behavior.

RESULTS

A 28-day course of low-dose lithium (human equivalent dose of 250 mg/day) combined with moderate-dose quetiapine (human equivalent dose of 600 mg/day) improved Ca²⁺ ratio by 70.10 %, PPI by 69.28 %, NOR by 70.09 %, MWM by 71.28 %, FCT by 68.56 %, EPM by 70.95 % and OFT by 75.23 % compared to the results of positive controls. Unexpectedly, moderate-dose lithium (human equivalent dose of 500 mg/day) used either as monotherapy or as an adjunct with quetiapine worsened Ca²⁺ activity, PPI, MWM, FCT, EPM, and OPT.

LIMITATIONS

Our study cannot explain the contrasting positive and negative effects of low-dose and moderate-dose lithium, respectively, when used either as monotherapies or as adjuncts. Further studies, especially Western blotting, may reveal molecular mechanisms of action.

CONCLUSIONS

Low-dose lithium (human equivalent dose of 250 mg/day) combined with moderate-dose quetiapine (human equivalent dose of 600 mg/day) provided the best improvements. Furthermore, benefits persisted for 14 days post-treatment. Our data provide directions for further research of therapeutic alternatives to mitigate schizophrenia-related cognopathy.

Recent Advances in Psychopharmacology: From Bench to Bedside Novel Trends in Schizophrenia

Research in the field of psychopharmacology is ongoing to develop novel compounds which can revolutionize the treatment of psychiatric disorders. The concept of bench-to-bedside is a tedious process, transforming the initial research performed in the laboratories into novel treatment options. Schizophrenia (SCZ) is a chronic psychiatric illness with significant morbidity and mortality. SCZ not only presents with psychotic symptoms including hallucinations and delusions but also with negative and cognitive symptoms. The negative symptoms include the diminished ability to express emotions, loss of pleasure, and motivation with minimal social interactions. Conventional antipsychotics primarily target positive symptoms with minimal therapeutic benefits for negative and cognitive symptoms along with metabolic side effects. Researchers have explored novel targets to develop new compounds to overcome the above limitations. The glutamatergic system has provided new hope in treating schizophrenia by targeting negative and cognitive symptoms. Other receptor modulators, including serotonergic, phosphodiesterase, trans-amine-associated receptors, etc., are novel targets for developing new compounds. Future research is required in this field to explore novel compounds and establish their efficacy and safety for the treatment of schizophrenia. Last but not least, pharmacogenomics has effectively utilized genetic information to develop novel compounds by minimizing the risk of failure of the clinical trials and enhancing efficacy and safety.

Impact of Physical Exercise Alone or in Combination with Cognitive Remediation on Cognitive Functions in People with Schizophrenia: A Qualitative Critical Review

Physical exercise and cognitive remediation represent the psychosocial interventions with the largest basis of evidence attesting their effectiveness in improving cognitive performance in people living with schizophrenia according to recent international guidance. The aims of this review are to provide an overview of the literature on physical exercise as a treatment for cognitive impairment in schizophrenia and of the studies that have combined physical exercise and cognitive remediation as an integrated rehabilitation intervention. Nine meta-analyses and systematic reviews on physical exercise alone and seven studies on interventions combining physical exercise and cognitive remediation are discussed. The efficacy of physical exercise in improving cognitive performance in people living with schizophrenia is well documented, but more research focused on identifying moderators of participants response and optimal modalities of delivery is required. Studies investigating the effectiveness of integrated interventions report that combining physical exercise and cognitive remediation provides superior benefits and quicker improvements compared to cognitive remediation alone, but most studies included small samples and did not explore long-term effects. While physical exercise and its combination with cognitive remediation appear to represent effective treatments for cognitive impairment in people living with schizophrenia, more evidence is currently needed to better understand how to implement these treatments in psychiatric rehabilitation practice.

Cognitive impairment in psychiatric diseases: Biomarkers of diagnosis, treatment, and prevention

Psychiatric diseases, such as schizophrenia, bipolar disorder, autism spectrum disorder, and major depressive disorder, place a huge health burden on society. Cognitive impairment is one of the core characteristics of psychiatric disorders and a vital determinant of social function and disease recurrence in patients. This review thus aims to explore the underlying molecular mechanisms of cognitive impairment in major psychiatric disorders and identify valuable biomarkers for diagnosis, treatment and prevention of patients.

Management of cognitive and negative symptoms in schizophrenia

Currently available antipsychotics provide only modest benefit in managing the cognitive and negative symptoms of schizophrenia even though these symptoms are often the most impairing in patients' daily lives. Certain antipsychotics may have slight benefits over others, and several nonpharmacologic and pharmacologic adjunctive treatments have been evaluated in recent clinical trials. Recently published meta-analyses and clinical studies of such treatments are reviewed. Potential strategies to manage cognitive and negative symptoms, including deprescribing of medications that may exacerbate these symptoms, are described using theoretical case examples.

Chronic N-Acetylcysteine Treatment Prevents Amphetamine-Induced Hyperactivity in Heterozygous Disc1 Mutant Mice, a Putative Prodromal Schizophrenia Animal Model

Symptoms of schizophrenia (SZ) typically emerge during adolescence to young adulthood, which gives a window before full-blown psychosis for early intervention. Strategies for preventing the conversion from the prodromal phase to the psychotic phase are warranted. Heterozygous (Het) Disc1 mutant mice are considered a prodromal model of SZ, suitable for studying psychotic conversion. We evaluated the preventive effect of chronic N-acetylcysteine (NAC) administration, covering the prenatal era to adulthood, on the reaction following the Amph challenge, which mimics the outbreak or conversion of psychosis, in adult Het Disc1 mice. Biochemical and morphological features were examined in the striatum of NAC-treated mice. Chronic NAC treatment normalized the Amph-induced activity in the Het Disc1 mice. Furthermore, the striatal phenotypes of Het Disc1 mice were rescued by NAC including dopamine receptors, the expression of GSK3s, MSN dendritic impairments, and striatal PV density. The current study demonstrated a potent preventive effect of chronic NAC treatment in Disc1 Het mice on the acute Amph test, which mimics the outbreak of psychosis. Our findings not only support the benefit of NAC as a dietary supplement for SZ prodromes, but also advance our knowledge of striatal dopamine receptors, PV neurons, and GSK3 signaling pathways as therapeutic targets for treating or preventing the pathogenesis of mental disorders.

Association between lipid metabolism and cognitive function in patients with schizophrenia

BACKGROUND

The association between blood lipids and cognitive function in schizophrenia is still controversial. Thus, the present study aimed to verify the association between various lipid parameters and cognitive impairment in schizophrenic patients and potential lipid pathways.

METHODS

A total of 447 adult inpatients with schizophrenia were divided into cognitive normal and cognitive impairment groups based on the Mini-Mental State Examination with a cut-off of 26. The blood lipid parameters were defined as abnormal levels based on the guideline. The liquid chromatography-mass spectrometry method was used to preliminarily explore the potential lipid metabolism pathway associated with cognitive impairment.

RESULTS

There were 368 (82.3%) patients who had cognitive impairment. Herein, apolipoprotein B was positively associated with cognitive function in overall patients and age (≥45 and <45 years) and sex subgroups. After excluding patients with hypertension and diabetes, ApoB was still significantly associated with cognitive function in all the patients. The associations between other lipid parameters, including non-high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride, and cognitive impairment were heterogeneous in age and sex subgroups. In contrast, total cholesterol and apolipoprotein A1 were not significantly associated with cognitive impairment. Metabolomics analysis showed that metabolic pathway mainly involved sphingolipid metabolism. Meanwhile, sphinganine and 3-dehydrosphinganine were positively correlated with lipid parameters and decreased in patients with cognitive impairment as compared to those with normal cognition.

CONCLUSIONS

The present study suggests a positive association between lipids and cognitive function in schizophrenic patients and needs to be further verified by a prospective study.