The Efficacy of Non-Pharmacological Interventions on Brain-Derived Neurotrophic Factor in Schizophrenia: A Systematic Review and Meta-Analysis

Keto therapy-unveiling the potential of ketogenic diet in psychiatric care: A scoping review

BACKGROUND

Within the framework of gut-brain interactions, the ketogenic diet (KD), a high-fat, low-carbohydrate, and moderate-protein dietary intervention, has gained attention for its potential in psychiatric care. Renowned for its efficacy in managing obesity, KD has demonstrated effectiveness in facilitating weight loss and inducing favorable metabolic changes in the short term. With its established benefits in neurological disorders, KD is now being investigated as a potential therapeutic avenue for individuals with psychiatric conditions.

OBJECTIVE

This scoping review aims to summarize the latest studies on this topic, consider clinical implications, and suggest future research directions.

METHODS

Records were systematically (PRISMA-ScR guidelines) identified through PubMed, Scopus, and EBSCOhost searches.

RESULTS

A total of 58 studies were initially identified, with 13 meeting the eligibility criteria. While clinical trials remain limited, emerging evidence from case reports, case series, and pilot studies highlights the potential of a KD in reducing symptoms across psychiatric conditions, including mood disorders, psychotic disorders, alcohol use, and eating disorders. A KD shows potential in reducing cravings in eating and alcohol use disorders by stabilizing brain metabolism and modulating addictive behaviors, while its neuroprotective and anti-inflammatory effects may contribute to symptom improvement in mood and psychotic disorders.

CONCLUSIONS

Implementing a KD in patients with mental disorders seems to be a feasible and well-tolerated approach, resulting in psychiatric symptom reduction and improvements in metabolic health. Most interestingly, research suggests that KD can also be safely implemented in the care of patients with addictive-like eating disorders.

Impact of Relapse in BDNF Receptors Expression in Patients With a First Episode of Schizophrenia

BACKGROUND AND HYPOTHESIS

Relapsing after a first episode of schizophrenia (FES) is a main predictor of clinical and functional prognosis. Brain-derived neurotrophic factor (BDNF) plays a critical role in neuronal development and plasticity, and its signaling may be altered by successive relapses.

DESIGN

We assessed the impact of first relapse in the expression of the 2 isoforms of the BDNF tropomyosin-related kinase B (TrkB) receptor (active full-length TrkB-F and inactive truncated TrkB-T) in peripheral blood mononuclear cells from 53 FES patients in clinical remission followed up for 3 years.

RESULTS

The group of participants that relapsed (n = 24) during the follow-up presented a significant decrease in the expression of the active TrkB-F receptor compared to baseline (M = 100 ± 28.13 vs. M = 83.42 ± 33.84, t = 2.5, P = .02), with no changes in the inactive TrkB-T receptor expression nor in BDNF plasma levels. This decrease also led to a significant decline in the F/T ratio (M = 1.13 ± 0.38 vs. 0.94 ± 0.36, t = 2.17, P = .041). No significant differences were found in the receptors' expression nor in plasma levels in the group of cases that remained in remission (n = 29). These results were not associated with baseline differences between the groups in terms of the BDNF signaling pathway biomarkers, clinical or treatment variables.

CONCLUSIONS

These findings highlight the biological impact that a relapse produces over the systemic BDNF-TrkB signaling pathway, potentially undermining crucial neuronal functions. Identifying the actors involved can help design specific interventions for relapse prevention and improve the functional prognosis of people in the early stages of schizophrenia.

Long-term effects of antipsychotics on serum BDNF levels in patients with schizophrenia

Brain-derived neurotrophic factor (BDNF) is implicated in the etiology of schizophrenia, and peripheral BDNF levels are affected by the short-term antipsychotic treatment. However, the data on their long-term effects on BDNF levels are scarce, and there is no information whether BDNF levels change during sustained remission in relation to values in healthy individuals. The aim of the present study was to compare serum BDNF levels in patients in long-term remission and healthy controls. This study is an extension of our previous research on the effects of olanzapine and risperidone on serum BDNF in acute-episode patients with schizophrenia. Patients who remained in remission for at least 3 years on the same antipsychotic regimen (40 % of the initial cohort) were included. Symptoms were assessed by the Positive and Negative Syndrome Scale (PANSS). Serum BDNF levels were measured by ELISA in patients in remission (N = 20), evaluated at baseline, after 6 weeks of treatment and after 3 years of treatment, and in healthy individuals (N = 40). At baseline (p = 0.046) and after 6 weeks of treatment (p = 0.028), patients had significantly lower BDNF levels than controls. However, after 3 years of continuous antipsychotic maintenance treatment, serum BDNF levels were increased compared to baseline and values after 6 weeks of treatment in remitted patients, and were also significantly higher in patients than in healthy controls (p = 0.002). Antipsychotic medications appear to have distinct effects on serum BDNF levels in short-and long-term treatment. It remains to be determined if such finding may be related to potential neuroprotective effects of antipsychotic maintenance treatment.

The importance of oxidative biomarkers in diagnosis, treatment, and monitoring schizophrenia patients

INTRODUCTION

The etiology of schizophrenia (SCZ), an incredibly complex disorder, remains multifaceted. Literature suggests the involvement of oxidative stress (OS) in the pathophysiology of SCZ.

OBJECTIVES

Determination of selected OS markers and brain-derived neurotrophic factor (BDNF) in patients with chronic SCZ and those in states predisposing to SCZ-first episode psychosis (FP) and ultra-high risk (UHR).

MATERIALS AND METHODS

Determination of OS markers and BDNF levels by spectrophotometric methods and ELISA in 150 individuals (116 patients diagnosed with SCZ or in a predisposed state, divided into four subgroups according to the type of disorder: deficit schizophrenia, non-deficit schizophrenia, FP, UHR). The control group included 34 healthy volunteers.

RESULTS

Lower activities of analyzed antioxidant enzymes and GSH and TAC concentrations were found in all individuals in the study group compared to controls (p < 0.001). BDNF concentration was also lower in all groups compared to controls except in the UHR subgroup (p = 0.01). Correlations were observed between BDNF, R-GSSG, GST, GPx activity, and disease duration (p < 0.02). A small effect of smoking on selected OS markers was also noted (rho<0.06, p < 0.03).

CONCLUSIONS

OS may play an important role in the pathophysiology of SCZ before developing the complete clinical pattern of the disorder. The redox imbalance manifests itself with such severity in individuals with SCZ and in a state predisposing to the development of this psychiatric disease that natural antioxidant systems become insufficient to compensate against it completely. The discussed OS biomarkers may support the SCZ diagnosis and predict its progression.

"InMotion"-Mixed physical exercise program with creative movement as an intervention for adults with schizophrenia: study protocol for a randomized controlled trial

Background

Schizophrenia is among the world's top 10 causes of long-term disability with symptoms that lead to major problems in social and occupational functioning, and in self-care. Therefore, it is important to investigate the efficacy of complementary treatment options for conventionally used antipsychotic medication, such as physical training, and psychosocial interventions.

Objective

To combine aerobic and strength training with cognitive, emotional and social stimulation in one intervention for people with schizophrenia and test the feasibility and effects of this intervention.

Methods

The study is a mixed-method randomized controlled trial to evaluate the effects of a 12-week intervention for adults with schizophrenia. The treatment group (30 participants) will receive the intervention in addition to standard care and the control group (30 participants) only standard care. The intervention consists of 24 biweekly sessions with a duration of 60 min. The pre-test (weeks from 4 to 2 prior to the intervention) and post-test (week 12) include clinical measure (PANSS), quality of life, social performance, movement quantity, brain function and eye tracking measures. In addition, a treatment subgroup of 12-15 participants and their family member or other next of kin will complete a qualitative interview as a part of their post-test. Two follow-up tests, including clinical, quality of life, brain function and eye tracking will be made at 6 and 12 months from the completion of the intervention to both study groups. The primary outcome is change in negative symptoms. Secondary outcome measures include general and positive symptoms, quality of life, social performance, movement quantity, brain function and eye tracking. Explorative outcome includes patient and family member or other next of kin interview.

Results

Pilot data was collected by June 2023 and the main data collection will begin in September 2023. The final follow-up is anticipated to be completed by 2026.

Conclusion

The InMotion study will provide new knowledge on the feasibility, efficacy, and experiences of a novel intervention for adults with schizophrenia. The hypothesis is that regular participation in the intervention will reduce clinical symptoms, normalize physiological measures such as brain activation, and contribute to new active habits for the participants.

Trial registration

ClinicalTrials.gov, identifier NCT05673941.

Lithium levels and lifestyle in patients with bipolar disorder: a new tool for self-management

BACKGROUND

Patients should get actively involved in the management of their illness. The aim of this study was to assess the influence of lifestyle factors, including sleep, diet, and physical activity, on lithium levels in patients with bipolar disorder.

METHODS

A multicenter study was performed. In total, 157 lithium measurements were done biweekly in a sample of 65 patients (35 women) over 6 weeks. Lifestyle, based on total sleep hours and physical activity, was assessed by actigraphy. Diet was evaluated using the Mediterranean Lifestyle Index (Medlife).

RESULTS

35.4% of patients had a normal weight. The mean Medlife score was 14.5 (± 2.5) (moderate-good adherence to Mediterranean diet). BMI, daily dose of lithium and intensity of physical activity had a combined effect on lithium levels, after adjustment for other variables. Patients who practiced intense physical exercise, who took lower doses and had a higher BMI exhibited lower levels of lithium.

CONCLUSIONS

Higher physical activity and BMI contribute to lower lithium levels. Patients should be made aware of these relationships to improve their perception of control and self-management. Lifestyle-based interventions contribute to establishing a more personalized medicine.

A combined exercise and cognitive training intervention induces fronto-cingulate cortical plasticity in first-episode psychosis patients

OBJECTIVE

Schizophrenia (SZ) is characterized by neurobiological and associated cognitive and functional deficits, including pronounced cortical thinning, that lead to acute and long-term functional impairment. Research with older adults supports the role of non-pharmacological interventions, such as exercise (E) and cognitive training (CT), for cognitive impairments. This literature influenced the development of combined CT&E treatments for individuals with SZ. However, the impact of longer combined treatment duration (6 months) on neuroanatomy has yet to be explored in patients in the early course of the illness. The impact of adding exercise to cognitive training for key brain regions associated with higher-order cognition was examined here using magnetic resonance imaging (MRI) in first-episode psychosis (FEP) patients.

METHODS

UCLA Aftercare Research Program patients with a recent first episode of schizophrenia were randomly assigned to either combined cognitive and exercise training (CT&E) (N = 20) or cognitive training alone (CT) (N = 17) intervention. Cortical thickness was measured longitudinally and analyzed for two regions of interest using FreeSurfer.

RESULTS

Compared to patients in the CT group, those in the CT&E group demonstrated an increase in cortical thickness within the left anterior cingulate cortex over the six-month treatment period (ACC: F(1, 35) = 4.666, P < .04). Directional tendencies were similar in the left dorsolateral prefrontal cortex (DLPFC: F(1,35) = 4.132, P < .05).

CONCLUSIONS

These findings suggest that exercise and cognitive training may synergistically increase fronto-cingulate cortical thickness to mitigate progressive neural atrophy in the early course of SZ. This combined intervention appears to be a valuable adjunct to standard pharmacologic treatment in FEP patients.

Association Between Depressive Symptoms and Serum Brain-Derived Neurotrophic Factor Levels in Patients With First-Episode and Drug-Naïve Schizophrenia

Previous studies have revealed that brain-derived neurotrophic factor (BDNF) levels are inversely associated with the severity of depressive symptoms. In addition, serum BDNF levels tend to increase with improvement in depressive symptoms. There is also evidence that BDNF has a possible role in the pathophysiology of schizophrenia. Therefore, the purpose of this study was to determine whether BDNF levels correlated with depressive symptoms in patients with first-episode and drug-naïve (FEDN) schizophrenia. In this study, 90 patients with FEDN schizophrenia and 60 healthy controls were recruited. The Positive and Negative Syndrome Scale (PANSS) and the 17-item Hamilton Depression Scale (HAMD-17) were used to gage psychopathological and depressive symptoms, respectively. All participants had their BDNF levels measured using a sandwich enzyme-linked immunosorbent test. Serum BDNF levels were lower in patients with FEDN schizophrenia compared with healthy controls. Moreover, patients with depressive symptoms exhibited a higher PANSS total score and a higher general psychopathology score than those without depressive symptoms (p < 0.05). For patients with depressive symptoms, serum BDNF levels were higher than in those without depressive symptoms (p < 0.05). An association between BDNF levels and the positive subscore was also observed (p < 0.01). However, there was no significant association between BDNF levels and HAMD scores (p > 0.05). In conclusion, BDNF levels were shown to be higher in the serum of patients with FEDN schizophrenia with depressive symptoms than in those without. Additionally, low levels of serum BDNF may contribute to the positive symptoms of FEDN schizophrenia but not to depressive symptoms.

The relationship between immune and cognitive dysfunction in mood and psychotic disorder: a systematic review and a meta-analysis

BACKGROUND

In psychotic and mood disorders, immune alterations are hypothesized to underlie cognitive symptoms, as they have been associated with elevated blood levels of inflammatory cytokines, kynurenine metabolites, and markers of microglial activation. The current meta-analysis synthesizes all available clinical evidence on the associations between immunomarkers (IMs) and cognition in these psychiatric illnesses.

METHODS

Pubmed, Web of Science, and Psycinfo were searched for peer-reviewed studies on schizophrenia spectrum disorder (SZ), bipolar disorder (BD), or major depressive disorder (MDD) including an association analysis between at least one baseline neuropsychological outcome measure (NP) and one IM (PROSPERO ID:CRD42021278371). Quality assessment was performed using BIOCROSS. Correlation meta-analyses, and random effect models, were conducted in Comprehensive Meta-Analysis version 3 investigating the association between eight cognitive domains and pro-inflammatory and anti-inflammatory indices (PII and AII) as well as individual IM.

RESULTS

Seventy-five studies (n = 29,104) revealed global cognitive performance (GCP) to be very weakly associated to PII (r = -0.076; p = 0.003; I² = 77.4) or AII (r = 0.067; p = 0.334; I² = 38.0) in the combined patient sample. Very weak associations between blood-based immune markers and global or domain-specific GCP were found, either combined or stratified by diagnostic subgroup (GCP x PII: SZ: r = -0.036, p = 0.370, I² = 70.4; BD: r = -0.095, p = 0.013, I² = 44.0; MDD: r = -0.133, p = 0.040, I² = 83.5). We found evidence of publication bias.

DISCUSSION

There is evidence of only a weak association between blood-based immune markers and cognition in mood and psychotic disorders. Significant publication and reporting biases were observed and most likely underlie the inflation of such associations in individual studies.

A Meta-Analysis of Brain-Derived Neurotrophic Factor Effects on Brain Volume in Schizophrenia: Genotype and Serum Levels

AIM

The Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene has established pleiotropic effects on schizophrenia incidence and morphologic alterations in the illness. The effects of brain-derived neurotrophic factor (BDNF) on brain volume measurements are however mixed seeming to be less established for most brain regions. The current meta-analytic review examined (1) the association of the Val66Met SNP and brain volume alterations in schizophrenia by comparing Met allele carriers to Val/Val homozygotes and (2) the association of serum BDNF with brain volume measurements.

METHOD

Studies included in the meta-analyses were identified through an electronic search of PubMed and PsycInfo (via EBSCO) for English language publications from January 2000 through December 2017. Included studies had conducted a genotyping procedure of Val66Met or obtained assays of serum BDNF and obtained brain volume data in patients with psychotic disorders. Nonhuman studies were excluded.

RESULTS

Study 1 which included 52 comparisons of Met carriers and Val/Val homozygotes found evidence of lower right and left hippocampal volumes among Met allele carriers with schizophrenia. Frontal measurements, while also lower among Met carriers, did not achieve statistical significance. Study 2 which included 7 examinations of the correlation between serum BDNF and brain volume found significant associations between serum BDNF levels and right and left hippocampal volume with lower BDNF corresponding to lower volumes.

DISCUSSION

The meta-analyses provided evidence of associations between brain volume alterations in schizophrenia and variations on the Val66Met SNP and serum BDNF. Given the limited number of studies, it remains unclear if BDNF effects are global or regionally specific.

The Influence of Psychotherapy on Peripheral Brain-Derived Neurotrophic Factor Concentration Levels and Gene Methylation Status: A Systematic Review

Psychotherapy is a well-established method of treating many mental disorders. It has been proven that psychotherapy leads to structural and functional changes in the brain; however, knowledge about the molecular and cellular mechanisms of these changes is limited. Neuroplasticity and one of its mediators, brain-derived neurotrophic factor (BDNF), are potential research targets in this field. To define the role of BDNF concentration in serum, or in plasma, and BDNF promoter gene methylation in saliva or leucocytes, in psychotherapy, an extensive literature search was conducted in the PubMed and Web of Science databases. The literature review was conducted based on papers published up until May 2021 that included pre and post psychotherapy measurements of either BDNF concentration levels or promoter gene methylation status. Ten studies were indicated as eligible for analysis: eight studies that investigated peripheral BDNF concentration levels, one study that investigated methylation status, and one study that included an evaluation of both subject matters. Patients underwent cognitive behavioral therapy or interpersonal psychotherapy. Patients were diagnosed with borderline personality disorder, major depressive disorder, anorexia nervosa, bulimia nervosa, or post-traumatic stress disorder. There were only three of the nine studies that showed statistically significant increases in BDNF concentration levels after psychotherapy. The two studies that involved BDNF gene methylation status showed a decrease in methylation after dialectical behavioral therapy of borderline patients.

A Multicentre, Randomised, Controlled Trial of a Combined Clinical Treatment for First-Episode Psychosis

Introduction: There is evidence that early intervention contributes to improving the prognosis and course of first-episode psychosis (FEP). However, further randomised treatment clinical trials are needed. Objectives: The aim of this study was to compare the efficacy of a combined clinical treatment involving Cognitive Behavioural Therapy (CBT) as an adjunctive to treatment-as-usual (TAU) (CBT+TAU) versus TAU alone for FEP. Patients and methods: In this multicentre, single-blind, randomised controlled trial, 177 participants were randomly allocated to either CBT+TAU or TAU. The primary outcome was post-treatment patient functioning. Results: The CBT+TAU group showed a greater improvement in functioning, which was measured using the Global Assessment Functioning (GAF) and Functioning Assessment Short Test (FAST), compared to the TAU group post-treatment. The CBT+TAU participants exhibited a greater decline in depressive, negative, and general psychotic symptoms; a better awareness of the disease and treatment adherence; and a greater increase in brain-derived neurotrophic factor levels than TAU participants. Conclusions: Early intervention based on a combined clinical treatment involving CBT as an adjunctive to standard treatment may improve clinical and functional outcomes in FEP.

The Emerging Role of BDNF/TrkB Signaling in Cardiovascular Diseases

Brain-derived neurotrophic factor (BDNF) is one of the most abundantneurotrophins in the central nervous system. Numerous studies suggestthat BDNF has extensive roles by binding to its specific receptor, tropomyosin-related kinase receptor B (TrkB), and thereby triggering downstream signaling pathways. Recently, growing evidence highlightsthat the BDNF/TrkB pathway is expressed in the cardiovascular system andclosely associated with the development and outcome of cardiovascular diseases (CVD), including coronary artery disease, heart failure, cardiomyopathy, hypertension, and metabolic diseases. Furthermore, circulating BDNF has also been revealed as a new potential biomarker for both diagnosis and prognosis of CVD. In this review, we discuss the current evidence of the emerging role of BDNF/TrkBsignalingand address the challenges that remain in translating these discoveries to novel therapeutic strategies for CVD.

BDNF as a Biomarker of Cognition in Schizophrenia/Psychosis: An Updated Review

Brain Derived Neurotrophic Factor (BDNF) has been linked to cognitive symptoms of schizophrenia, which has been documented in previous reviews by several authors. However, a trend has recently emerged in this field moving from studying schizophrenia as a disease to studying psychosis as a group. This review article focuses on recent BDNF studies in relation to cognition in human subjects during different stages of the psychotic process, including subjects at high risk of developing psychosis, patients at their first episode of psychosis, and patients with chronic schizophrenia. We aim to provide an update of BDNF as a biomarker of cognitive function on human subjects with schizophrenia or earlier stages of psychosis, covering new trends, controversies, current research gaps, and suggest potential future developments in the field. We found that most of current research regarding BDNF and cognitive symptoms in psychosis is done around schizophrenia as a disease. Therefore, it is necessary to expand the study of the relationship between BDNF and cognitive symptoms to psychotic illnesses of different stages and origins.

Cannabis use influence on peripheral brain-derived neurotrophic factor levels in antipsychotic-naïve first-episode psychosis

The objective of this study is to determine whether cannabis influences BDNF levels in patients with psychosis (FEP) and healthy volunteers (HV) to help understand the role of BDNF in psychosis. We assessed the association between BDNF and cannabis in a cohort of FEP antipsychotic-naïve patients and HV, whilst controlling for other potential confounding factors. 70 FEP drug-naive patients and 57 HV were recruited. A sociodemographic variable collection, structured clinical interview, weight and height measurement, substance use determination, and blood collection to determine BDNF levels by ELISA analysis were done. In FEP patients, cannabis use was associated with BDNF levels (high cannabis use was associated with lower BDNF levels). Moreover, cannabis use was statistically significantly associated with age (high use of cannabis was associated with younger age). In HV, no relationship between cannabis use and BDNF levels was observed. Otherwise, cannabis use was significantly associated with tobacco use, so that high cannabis users were also high tobacco users. This study showed a different association between cannabis use and BDNF levels in FEP patients compared with HV, particularly, with high doses of cannabis. These findings may help understand the deleterious effects of cannabis in some vulnerable individuals, as well as discrepancies in the literature.

The Epigenetic Overlap between Obesity and Mood Disorders: A Systematic Review

(1) Background: Obesity and mood disorders are considered as the most prevalent morbidities in many countries. We suppose that epigenetic mechanisms may induce higher rates of obesity in subjects who suffer from mood disorders. In this systematic review, we focused on the potential roles of DNA methylation on mood disorders and obesity development. (2) Methods: This systematic review was conducted in accordance with the PRISMA statement and registered in Prospero. A systematic search was conducted in MEDLINE, Scopus, Web of Science, Cochrane Central database, EMBASE, and CINHAL. We also conducted a Grey literature search, such as Google Scholar. (3) Results: After deduplication, we identified 198 potentially related citations. Finally, ten unique studies met our inclusion criteria. We have found three overlap genes that show significant DNA methylation changes, both in obesity and depression. Pathway analysis interaction for TAPBP, BDNF, and SORBS2 confirmed the relation of these genes in both obesity and mood disorders. (4) Conclusions: While mechanisms linking both obesity and mood disorders to epigenetic response are still unknown, we have already known chronic inflammation induces a novel epigenetic program. As the results of gene enrichment, pathways analysis showed that TAPBP, BDNF, and SORBS2 linked together by inflammatory pathways. Hypermethylation in these genes might play a crucial rule in the co-occurrence of obesity and mood disorders.

Medial temporal lobe cortical changes in response to exercise interventions in people with early psychosis: A randomized controlled trial

OBJECTIVE

Individuals with early psychosis may have prefrontal-limbic cortical deficits, which are associated with symptom severity and cognitive impairment. This study investigated the impact of an exercise intervention on fronto-temporal cortical plasticity in female participants with early psychosis.

METHODS

In a cohort of 51 female participants with early psychosis from Hong Kong, we investigated the effects of a 12-week, moderate intensity aerobic or Hatha yoga exercise trial (yoga (N = 21), aerobic (N = 18) or waitlist group (N = 12)) on cortical grey matter. Clinical assessments and structural MRI were completed pre- and post- a 12-week exercise intervention.

RESULTS

Increases in cortical volume and thickness were observed in the medial temporal cortical regions, primarily in fusiform cortical thickness (F(2, 48) = 4.221, p = 0.020, η² = 0.150) and volume (F(2, 48) = 3.521, p = 0.037, η² = 0.128) for participants with early psychosis in the aerobic arm, but not in the yoga and waitlist arms. Increased fusiform cortical thickness (ß = 0.402, p = 0.003) was associated with increased hippocampal volume for all psychosis participants. For the aerobic group only, increases in the entorhinal and fusiform temporal gyri were associated with reduced symptom severity.

CONCLUSIONS

These findings suggest exercise-induced neuroplasticity in medial temporal cortical regions occurs with aerobic exercise. These changes may be associated with improvements in psychosis symptom severity. People with early psychosis may benefit from exercise interventions, particularly aerobic exercise, as an adjunct treatment to address clinical, physical health, and neuroanatomic concerns. NIH National Library of Medicine ClinicalTrials.gov Registration #: NCT01207219https://clinicaltrials.gov/ct2/show/NCT01207219.

Dietary modification in the treatment of schizophrenia spectrum disorders: A systematic review

BACKGROUND

Schizophrenia spectrum disorders impact functioning, reduce quality of life and increase the risk of physical illness and premature mortality. Nutritional intervention studies aimed at decreasing body weight have demonstrated efficacy in improving metabolic outcomes; however, few studies have explored the impact of interventions designed to modify diet on mental health outcomes.

AIM

To synthesize the existing experimental studies of adjunctive diet modification as an intervention in the treatment of psychotic disorders, analyze findings related to effectiveness and safety, highlight knowledge gaps and limitations, and set forward recommendations for future research studies.

METHODS

An extensive a priori search strategy was developed and the databases Embase, Embase Classic, Ovid MEDLINE were searched. Screening and data extraction were completed in duplicate. Studies included in this analysis were experimental studies of an adjunctive dietary intervention (overall dietary pattern or education on dietary change) for treatment of schizophrenia spectrum disorders. No restrictions were placed on control groups or blinding. The studies were required to report a mental health outcome.

RESULTS

Twenty-five clinical trials were identified, along with two additional protocols and two meta-analyses. Nineteen of the clinical trials reported improvement in one or more mental health domain including psychosis symptoms, cognition, and quality of life. A high level of heterogeneity was found with respect to patient population, intervention, and study design. All of the studies included lifestyle or psychosocial components in addition to dietary modification. The nutrition advice provided to participants was poorly described overall and compliance was not assessed. The studies that showed benefit tended to have a smaller sample size and were less likely to be randomized but were more likely to use a group delivery intervention.

CONCLUSION

Further research assessing effectiveness and efficacy of clearly reported dietary interventions is warranted, especially those using rigorous methodology, modifying diet in isolation and assessing participant compliance.

Exercise and Schizophrenia

Schizophrenia is a psychiatric disorder characterized by distortions of thinking and perception, with no strictly pathognomonic symptoms that can be divided into positive, negative, and cognitive symptom domains. People with schizophrenia have, between others, a reduced life expectancy and cardiorespiratory and muscular fitness and increased risk of cardiovascular disease, metabolic syndrome, obesity, hypertension, and hyperlipidemia compared to the general population. Furthermore, the economic burden of mental disorders including schizophrenia is evident and it is expected to increase to more than double by 2030. Therefore, reducing the growing burden of mental disorders such as schizophrenia should be a health priority. Improved prevention and treatment are two key factors that may reduce the burden of schizophrenia. Pharmacological- and psychotherapy-based interventions have been traditionally considered for treating schizophrenia disorders; however, there is an increasing amount of scientific evidence confirming that physical activity and physical exercise should be highly considered in prevention and treatment of schizophrenia disorders. In this chapter, we aim to summarize and discuss the research progress of physical activity and exercise in prevention and treatment of schizophrenia disorder. Specifically, we summarized and discussed the research progress of the prognostic use of physical activity for incident schizophrenia; the importance of other outcomes typically improved by physical activity/exercise such as obesity and fitness (cardiorespiratory and muscular fitness) for future schizophrenia; the research progress of the evidence of the benefits of exercise in people with schizophrenia disorders differentiating between effects of exercise on varied health outcomes, cognitive functioning, and cardiorespiratory fitness; and finally the clinical practice recommendations.

Assessment of psychiatric and behavioral adverse effects of antiepileptic drugs monotherapy: Could they have a neuroendocrine correlation in persons with epilepsy?

OBJECTIVE

The study investigated overall adverse event (AE) burden and specifically psychiatric and behavioral side effects (PBAEs) in persons with epilepsy (PWE) on antiepileptic drugs (AEDs) monotherapy. It also assessed their correlation with neuroendocrine and oxidative stress biomarkers.

METHODS

This cross-sectional observational study was conducted at a tertiary care hospital between 2016 and 2018. Persons with epilepsy above 18 years on monotherapy of levetiracetam (LEV) and conventional AEDs {carbamazepine (CBZ), phenytoin (PHT), or valproate (VPA)} for at least 6 months were enrolled. Validated questionnaires, 'Mini-International Neuropsychiatric Interview (MINI 7.02)', 'Depression, Anxiety, and Stress Scale 21 (DASS-21)', 'Buss-Perry Aggression Questionnaire (BPAQ)', 'patient-weighted Quality of life Index in Epilepsy (QOLIE-10)', 'Pittsburgh Sleep Quality Index (PSQI)', and 'Liverpool Adverse Events Profile (LAEP)' were used to assess the PBAEs, quality of life, sleep quality, and AE profile. A subgroup of PWE recruited consecutively were considered for estimation of the following neuroendocrine biomarker levels: brain-derived neurotrophic factor (BDNF), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and total antioxidant capacity (TAC) which were then correlated with scores of above questionnaires.

RESULTS

After screening 220 PWE, 163 PWE (58 on LEV and 105 on conventional AEDs) with a mean age of 29 ± 10 years were enrolled. Mini-International Neuropsychiatric Interview revealed that LEV group had higher association with PBAEs and lower quality of sleep compared to conventional AEDs (p = 0.032 and 0.046, respectively). Other scales did not show significant difference between LEV and conventional AEDs. In the subset of PWE (n = 74, 36 on LEV and 38 on conventional AEDs), LEV group had more association with the PBAEs (p = 0.010), higher physical aggression and anger components of BPAQ (p = 0.03 and 0.02, respectively), and more AE (p = 0.049) than conventional AED group. However, there was no significant difference in neuroendocrine biomarker levels.

CONCLUSION

Levetiracetam had a higher association with PBAEs and more AE when compared to conventional AEDs. There was no differential correlation of AEDs with the following neuroendocrine markers: BDNF, HVA, 5-HIAA, and TAC. These facts necessitate exploration of other mechanisms for LEV-induced PBAEs.

Sensory-targeted cognitive training for schizophrenia

INTRODUCTION

Auditory and visual dysfunctions are key pathophysiological features of schizophrenia (Sz). Therefore, remedial interventions that directly target such impairments could potentially drive gains in higher-order cognition (e.g., memory, executive functions, emotion processing), symptoms and functional outcome, in addition to improving sensory abilities in this population. Here, we reviewed available sensory-targeted cognitive training (S-TCT) programs that were investigated so far in Sz patients. Area covered: A systematic review of the literature was conducted following PRISMA guidelines. Twenty-seven relevant records were included. The superiority of S-TCT over control conditions on higher-order cognition measures was repeatedly demonstrated, but mostly lost significance at later endpoints of evaluation. Clinical symptoms and functional outcome were improved in a minority of studies. S-TCT interventions were associated with the relative normalization of several neurobiological biomarkers of neuroplasticity and sensory mechanisms. Expert commentary: S-TCT, although time-intensive, is a cost-efficient, safe and promising technique for Sz treatment. Its efficacy on higher-order cognition opens a critical window for clinical and functional improvement. The biological impact of S-TCT may allow for the identification of therapeutic biomarkers to further precision-medicine. Additional research is required to investigate the long-term effects of S-TCT, optimal training parameters and potential confounding factors associated with the illness.

Mindfulness-based program for stress reduction in infertile women: Randomized controlled trial

Infertile women often experience chronic stress, which may have a negative impact on general well-being and may increase the burden of infertility. In this open-label, parallel, randomized controlled trial, infertile women aged 18-50 years (median 37 years) were assigned to an 8-week mindfulness-based program (MBP) or no intervention. The primary outcome was stress severity measured by the Lipp's Stress Symptoms Inventory (ISSL). Data were analyzed by modified intent-to-treat principle, which included all cases available to follow-up regardless of adherence to the intervention (62 participants from the MBP group and 37 from the control group). The median number of symptoms of chronic stress recorded in the past month decreased from six (interquartile range 2 to 9) before the MBP to two (interquartile range 1 to 4) after the intervention (p < 0.001, repeated measures analysis of variance with Time × Group interaction). Depressive symptoms also decreased after MBP, whereas general well-being improved (p < 0.01 for both outcomes). Hair cortisol and serum brain-derived neurotrophic factor (BDNF) did not change significantly between preintervention and postintervention. None of the outcomes changed significantly in the control group. MBP was effective in reducing stress and depressive symptoms while increasing general well-being in infertile women.

Elevated brain-derived neurotrophic factor (BDNF) serum levels in an acute episode of schizophrenia in polish women: Correlation with clinical and metabolic parameters

Brain-derived neurotrophic factor (BDNF) has been implicated in the pathogenesis of psychiatric disorders. Schizophrenia is associated with metabolic abnormalities and BDNF regulates energy homeostasis and glucose metabolism in peripheral tissues. The aim of this study was to examine serum levels of BDNF in schizophrenic women during 8 weeks of treatment and control group, and its correlation with clinical and metabolic parameters. The study was performed on a group of 96 women: 55 diagnosed with paranoid schizophrenia according to DSM-IV criteria, and 41 healthy controls. Positive and Negative Syndrome Scale (PANSS) was used to assess the severity of schizophrenia. BDNF serum levels and metabolic parameters: fasting serum glucose, total cholesterol, triglyceride (TG), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C) were measured at baseline and week 8 of treatment. BDNF serum levels were significantly elevated in medicated patients with schizophrenia comparing to controls. After 8 weeks of antipsychotic treatment, BDNF levels did not significantly change. Increase in TG and TG/HDL-C ratio and a decrease in HDL-C was detected in medicated patients. Correlation between BDNF and lipid profile as well as symptoms severity was found. In our study we detected abnormalities in BDNF levels and lipid profile in medicated schizophrenic women in Polish population.

Correlates of neurocognitive functions in individuals at ultra-high risk for psychosis - A 6-month follow-up study

Cognitive deficits are evident at the prodromal phase of psychosis. It has been noted that brain-derived neurotrophic factor (BDNF) is correlated with cognition in both preclinical and clinical studies. However, to our knowledge, no study has evaluated blood BDNF levels and their association with cognitive impairment in individuals at ultra-high risk for psychosis (UHR). We included 13 individuals at UHR and 30 healthy controls (HC) matched by sex, age, and educational level. Plasma BDNF levels were measured at baseline and 6 months. Neurocognitive functions (executive functions, speed of processing, verbal learning and memory, working memory) were examined at 6 months. Regression analyses were conducted to examine the relationship between BDNF levels and cognitive performance. BDNF levels were lower in UHR group than in HC group both at baseline and at 6 months (P = 0.001, and P = 0.007, respectively). There were no associations between plasma BDNF levels and all of the cognitive domains in both groups. Our findings showed that peripheral BDNF levels were not related to cognitive deficits in UHR and HC groups while the lower BDNF level in the former persisted up to 6 months. Further research is needed in a large sample.

Association between Obesity and Circulating Brain-Derived Neurotrophic Factor (BDNF) Levels: Systematic Review of Literature and Meta-Analysis

Reduction in brain-derived neurotrophic factor (BDNF) expression in the brain as well as mutations in BDNF gene and/or of its receptor are associated to obesity in both human and animal models. However, the association between circulating levels of BDNF and obesity is still not defined. To answer this question, we performed a meta-analysis carrying out a systematic search in electronic databases. Ten studies (307 obese patients and 236 controls) were included in the analysis. Our data show that obese patients have levels of BDNF similar to those of controls (SMD: 0.01, 95% CI: −0.28, 0.30, p = 0.94). The lack of difference was further confirmed both in studies in which BDNF levels were assessed in serum (MD: −0.93 ng/mL, 95% CI: −3.34, 1.48, p = 0.45) and in plasma (MD: 0.15 ng/mL, 95% CI: −0.09, 0.39, p = 0.23). Data evaluation has shown that some bias might affect BDNF measurements (e.g., subject recruitment, procedures of sampling, handling, and storage), leading to a difficult interpretation of the results. Standardization of the procedures is still needed to reach strong, affordable, and reliable conclusions.

[Physical activity in patients with schizophrenia: From neurobiology to clinical benefits]

Schizophrenia is a severe chronic mental disorder that mainly manifests by positive symptoms, negative symptoms, disorganized behavior and thought and cognitive impairments. Taken together, these symptoms have substantial impact on quality of life, well-being and functional outcome. Patients with schizophrenia have dramatically higher levels of cardiovascular and metabolic morbidity than the general population due to poor physical fitness and to sedentary lifestyle. They have a reduced life expectancy, and an excess mortality being two or three times more than that in the general population. Moreover, despite major therapeutic advances in the overall management of these patients, some symptomatic dimensions, and more specifically the negative and cognitive ones, remain to be resistant to the usual pharmacological approaches. Moreover, antipsychotics can also reinforce the global cardiovascular risk due to side effects and low neurometabolic tolerance. The benefits of physical activity on health are now well described in the general population and in many medical diseases. More recently, physical activity has also found its place as an adjuvant therapy in severe mental illnesses, particularly in schizophrenia. In the literature physical activity programs, in addition to pharmacological treatments, appear to be feasible in patients and improve both physical and mental health as well as functional outcome. Clinical benefits of physical activity would be underpinned by biological and cerebral mechanisms, which remain unclear. In this review, we propose to present a state of the art and to present an update of the interests of physical activity in the management of patients with schizophrenia. We emphasize the clinical benefits of physical activity regarding the different symptomatic dimensions and its impact specifically on cognitive deficits. Finally, we describe the various underlying pathophysiological mechanisms in particular in the neurobiological, cerebral and physiological fields. We then discuss the barriers, facilitators and motivating factors towards physical activity to enhance health promotion initiatives, to optimize resource allocation when delivering physical activity programs in clinical practice, and to maximize physical activity participation. Physical activity appears to be an original and novel adjunctive therapeutic approach in the management of patients with schizophrenia and would both reduce schizophrenic symptoms and act like pro-cognitive therapy, improve quality of life and long-term functioning in daily life and reduce cardiovascular comorbidities. However, efforts are still needed to increase the motivating factors and adherence towards physical activity participation for people with schizophrenia.

The involvement of DARPP-32 in the pathophysiology of schizophrenia

Schizophrenia is one of the most devastating heterogeneous psychiatric disorders. The dopamine hypothesis is the longest standing pathoetiologic theory of schizophrenia based on neurochemical evidences of elevated brain striatal dopamine synthesis capacity and increased dopamine release in response to stress. Dopamine and cyclic AMP-regulated phosphoprotein of relative molecular mass 32,000 (DARPP-32) is a cytosolic protein highly enriched in the medium spiny neurons of the neostriatum, considered as the most important integrator between the cortical input and the basal ganglia, and associated with motor control. Accumulating evidences has indicated the involvement of DARPP-32 in the development of schizophrenia; i. DARPP-32 phosphorylation is regulated by several neurotransmitters, including dopamine and glutamate, neurotransmitters implicated in schizophrenia pathogenesis; ii. decrease of both total and phosphorylated DARPP-32 in the prefrontal cortex are observed in schizophrenic animal models; iii. postmortem brain studies indicated decreased expression of DARPP-32 protein in the superior temporal gyrus and dorsolateral prefrontal cortex in patients with schizophrenia; iv. DARPP-32 phosphorylation is increased upon therapy with antipsychotic drugs, such as haloperidol and risperidone which improve behavioral performance in experimental animal models and patients; v. Genetic analysis of the gene coding for DARPP-32 propose an association with schizophrenia. Cumulatively, these findings implicate DARPP-32 protein in schizophrenia and propose it as a potential therapeutic target. Here, we summarize the possible roles of DARPP-32 during the development of schizophrenia and make some recommendations for future research. We propose that DARPP-32 and its interacting proteins may serve as potential therapeutic targets in the treatment of schizophrenia.