Melatonin: an overlooked factor in schizophrenia and in the inhibition of anti-psychotic side effects

The clock is ticking on schizophrenia: a study protocol for a translational study integrating phenotypic, genomic, microbiome and biomolecular data to overcome disability

Background

Shared biological factors may play a role in both the cognitive deficits and the increased prevalence of metabolic syndrome observed in individuals with Schizophrenia (SCZ). These factors could entail disturbances in tryptophan (Trp) to both melatonin (MLT) and kynurenine (Kyn) metabolic pathways, as well as inflammation and alterations in the gut microbiome composition.

Methods

The present research project aims to investigate this hypothesis by recruiting 170 SCZ patients from two different recruitment sites, assessing their cognitive functions and screening for the presence of metabolic syndrome. Additionally, we plan to assess the impact of a 3-month cognitive remediation therapy on 30 of these patients. We will analyze clinical data alongside serum biomarkers and gene expression related to the Trp- to MLT and Kyn metabolic pathways, markers of inflammatory and composition of the gut microbiome. The association between Trp-MLT-Kyn levels, expression levels of selected genes, inflammatory markers and clinical phenotypes will be analyses in the context of general linear models.

Discussion

This project has the potential to identify some typical SCZ symptomatic clusters that will be more stringently associated with variations in the Trp-MLT-Kyn/inflammatory system and with a better response to cognitive remediation therapy. Moreover, in a future perspective, it may highlight a group of patients who may benefit from a pharmacological treatment aiming at reinstating the physiological Trp to MLT and Kyn system. Therefore, it has the potential to move research toward a personalized approach for SCZ management.

Modulation of neural circuits by melatonin in neurodegenerative and neuropsychiatric disorders

Neurodegenerative and neuropsychiatric disorders are two broad categories of neurological disorders characterized by progressive impairments in movement and cognitive functions within the central and peripheral nervous systems, and have emerged as a significant cause of mortality. Oxidative stress, neuroinflammation, and neurotransmitter imbalances are recognized as prominent pathogenic factors contributing to cognitive deficits and neurobehavioral anomalies. Consequently, preventing neurodegenerative and neuropsychiatric diseases has surfaced as a pivotal challenge in contemporary public health. This review explores the investigation of neurodegenerative and neuropsychiatric disorders using both synthetic and natural bioactive compounds. A central focus lies on melatonin, a neuroregulatory hormone secreted by the pineal gland in response to light-dark cycles. Melatonin, an amphiphilic molecule, assumes multifaceted roles, including scavenging free radicals, modulating energy metabolism, and synchronizing circadian rhythms. Noteworthy for its robust antioxidant and antiapoptotic properties, melatonin exhibits diverse neuroprotective effects. The inherent attributes of melatonin position it as a potential key player in the pathophysiology of neurological disorders. Preclinical and clinical studies have demonstrated melatonin's efficacy in alleviating neuropathological symptoms across neurodegenerative and neuropsychiatric conditions (depression, schizophrenia, bipolar disorder, and autism spectrum disorder). The documented neuroprotective prowess of melatonin introduces novel therapeutic avenues for addressing neurodegenerative and psychiatric disorders. This comprehensive review encompasses many of melatonin's applications in treating diverse brain disorders. Despite the strides made, realizing melatonin's full neuroprotective potential necessitates further rigorous clinical investigations. By unravelling the extended neuroprotective benefits of melatonin, future studies promise to deepen our understanding and augment the therapeutic implications against neurological deficits.

Total antioxidant capacity, obesity and clinical correlates in first-episode and drug-naïve patients with schizophrenia

BACKGROUND

Overweight/obesity is a growing concern in schizophrenia (SZ). A few studies have shown that excessive oxidative stress and abnormal antioxidants were associated with pathogenesis and psychiatric symptoms in first episode antipsychotics naïve (FEAN) patients with SZ. However, there is no study has explored the interrelationships between total antioxidant status (TAS) and the severity of psychiatric symptoms in the early stage of SZ. This study aimed to evaluate the impact of overweight/obesity on psychiatric symptoms in FEAN patients with SZ.

METHODS

A total of 241 patients with FEAN SZ and 119 healthy controls were recruited and symptoms were evaluated by the Positive and Negative Syndrome Scale (PANSS). TAS levels were also measured in patients and healthy controls.

RESULTS

We found a significant negative association between body mass index (BMI) and TAS in FEAN patients, but not in controls. In addition, BMI and TAS were negatively associated with psychiatric symptoms. Interestingly, further regression analysis revealed that the interaction between BMI and TAS was associated with the negative symptoms in the early stage of SZ.

CONCLUSIONS

Our study indicates that abnormal TAS levels interacting with overweight/obesity may be involved in the pathophysiology of SZ, in particular negative symptoms.

Sleep disturbances and the association with attenuated psychotic symptoms in individuals at ultra high-risk of psychosis

Sleep disturbances are common in individuals at ultra high-risk (UHR) of psychosis and have proven to play a causal role in the occurrence of psychotic symptoms in healthy individuals. Only a few studies have systematically investigated sleep disturbances in UHR individuals. The help-seeking UHR individuals were 18-40 years old, and we included 72 UHR individuals according to the Comprehensive Assessment of At-Risk Mental State criteria (CAARMS) and 36 healthy controls. Sleep was measured with a modified version of the Karolinska Sleep Questionnaire and actigraphy for one night, and melatonin was measured at awakening and bedtime. We compared subjective rated sleep and actigraphy between healthy and UHR individuals (t-test and chi-square test) and examined the association between a CAARMS-composite score (linear regression). UHR individuals subjectively experienced poor sleep, categorised as disturbed sleep- and awakening index compared with healthy controls. We found no differences in actigraphy variables or morning/evening melatonin between UHR and healthy controls (t-test and chi-square). A high CAARMS-composite score was associated with high morning melatonin (B = 0.15, CI 0.02 to 0.27, p = 0.024) and high awakening index (B = 1.86, CI 0.58 to 3.14, p = 0.004) in UHR individuals. The results suggest that UHR individuals with high CAARMS scores have a delayed sleep phase; they have difficulties waking up and feel exhausted at awakening. It might be necessary to evaluate how UHR individuals sleep, and it would be of great interest to follow these patients over time according to the development of psychosis.

Pharmacological Strategies for Bipolar Disorders in Acute Phases and Chronic Management with a Special Focus on Lithium, Valproic Acid, and Atypical Antipsychotics

Bipolar disorders (BDs) are a heterogeneous group of severe affective disorders generally described by the alternation of (hypo)manic, depressive, and mixed phases, with euthymic intervals of variable duration. BDs are burdened with high psychiatric and physical comorbidity, increased suicide risk and reduced life expectancy. In addition, BDs can progress into complicated forms (e.g., mixed states, rapid/irregular cycling), which are more difficult to treat and often require personalized pharmacological combinations. Mood stabilizers, particularly Lithium and Valproic acid (VPA), still represent the cornerstones of both acute and chronic pharmacotherapies of BDs. Lithium is the gold standard in BD-I and BDII with typical features, while VPA seems more effective for atypical forms (e.g., mixed-prevalence and rapid-cycling). However, despite appropriate mood stabilization, many patients show residual symptoms, and more than a half recur within 1-2 years, highlighting the need of additional strategies. Among these, the association of atypical antipsychotics (AAPs) with mood stabilizers is recurrent in the treatment of acute phases, but it is also being growingly explored in the maintenance pharmacotherapy. These combinations are clinically more aggressive and often needed in the acute phases, whereas simplifying pharmacotherapies to mood stabilizers only is preferable in the long-term, whenever possible. When mood stabilizers are not enough for maintenance treatment, Quetiapine and, less consistently, Aripiprazole have been proposed as the most advisable adjunctive strategies, for their safety and tolerability profiles. However, in view of the increased risk of serious adverse effects, a careful patient-centered balance between costs and benefits is mandatory.

Schizophrenia Hypothesis: Autonomic Nervous System Dysregulation of Fetal and Adult Immune Tolerance

The autonomic nervous system can control immune cell activation via both sympathetic adrenergic and parasympathetic cholinergic nerve release of norepinephrine and acetylcholine. The hypothesis put forward in this paper suggests that autonomic nervous system dysfunction leads to dysregulation of immune tolerance mechanisms in brain-resident and peripheral immune cells leading to excessive production of pro-inflammatory cytokines such as Tumor Necrosis Factor alpha (TNF-α). Inactivation of Glycogen Synthase Kinase-3β (GSK3β) is a process that takes place in macrophages and microglia when a toll-like receptor 4 (TLR4) ligand binds to the TLR4 receptor. When Damage-Associated Molecular Patterns (DAMPS) and Pathogen-Associated Molecular Patterns (PAMPS) bind to TLR4s, the phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) pathway should be activated, leading to inactivation of GSK3β. This switches the macrophage from producing pro-inflammatory cytokines to anti-inflammatory cytokines. Acetylcholine activation of the α7 subunit of the nicotinic acetylcholine receptor (α7 nAChR) on the cell surface of immune cells leads to PI3K/Akt pathway activation and can control immune cell polarization. Dysregulation of this pathway due to dysfunction of the prenatal autonomic nervous system could lead to impaired fetal immune tolerance mechanisms and a greater vulnerability to Maternal Immune Activation (MIA) resulting in neurodevelopmental abnormalities. It could also lead to the adult schizophrenia patient’s immune system being more vulnerable to chronic stress-induced DAMP release. If a schizophrenia patient experiences chronic stress, an increased production of pro-inflammatory cytokines such as TNF-α could cause significant damage. TNF-α could increase the permeability of the intestinal and blood brain barrier, resulting in lipopolysaccharide (LPS) and TNF-α translocation to the brain and consequent increases in glutamate release. MIA has been found to reduce Glutamic Acid Decarboxylase mRNA expression, resulting in reduced Gamma-aminobutyric acid (GABA) synthesis, which combined with an increase of glutamate release could result in an imbalance of glutamate and GABA neurotransmitters. Schizophrenia could be a “two-hit” illness comprised of a genetic “hit” of autonomic nervous system dysfunction and an environmental hit of MIA. This combination of factors could lead to neurotransmitter imbalance and the development of psychotic symptoms.

Pineal morphology of the clinical high-risk state for psychosis and different psychotic disorders

BACKGROUND

Pineal volume reductions have been reported in schizophrenia and clinical high-risk states for the development of psychosis, supporting the role of melatonin dysregulation in the pathophysiology of psychosis. However, it remains unclear whether pineal volume is associated with the later onset of psychosis in individuals at clinical high-risk (CHR) of psychosis or if pineal atrophy is specific to schizophrenia among different psychotic disorders.

METHODS

This magnetic resonance imaging study examined the volume of and cyst prevalence in the pineal gland in 135 individuals at CHR of psychosis [52 (38.5%) subsequently developed psychosis], 162 with first-episode psychosis (FEP), 89 with chronic schizophrenia, and 87 healthy controls. The potential contribution of the pineal morphology to clinical characteristics was also examined in the CHR and FEP groups.

RESULTS

Pineal volumes did not differ significantly between the CHR, FEP, and chronic schizophrenia groups, but were significantly smaller than that in healthy controls. However, pineal volumes were not associated with the later onset of psychosis in the CHR group or FEP sub-diagnosis (i.e., schizophrenia, schizophreniform disorder, affective psychosis, and other psychoses). No significant differences were observed in the prevalence of pineal cysts between the groups, and it also did not correlate with clinical characteristics in the CHR and FEP groups.

CONCLUSION

These results suggest that pineal atrophy is a general vulnerability marker of psychosis, while pineal cysts do not appear to contribute to the pathophysiology of psychosis.

Potential contribution of pineal atrophy and pineal cysts toward vulnerability and clinical characteristics of psychosis

BACKGROUND

Magnetic resonance imaging (MRI) studies reported pineal gland atrophy in schizophrenia patients and individuals at a clinical high risk of developing psychosis, implicating abnormalities in melatonin secretion in the pathophysiology of psychosis. However, it currently remains unclear whether the morphology of the pineal gland contributes to symptomatology and sociocognitive functions.

METHODS

This MRI study examined pineal gland volumes and the prevalence of pineal cysts as well as their relationship with clinical characteristics in 57 at risk mental state (ARMS) subjects, 63 patients with schizophrenia, and 61 healthy controls. The Social and Occupational Functioning Assessment Scale (SOFAS), the Schizophrenia Cognition Rating Scale (SCoRS), and the Brief Assessment of Cognition in Schizophrenia (BACS) were used to assess sociocognitive functions, while the Positive and Negative Syndrome Scale was employed to evaluate clinical symptoms in ARMS subjects and schizophrenia patients.

RESULTS

Pineal gland volumes were significantly smaller in the ARMS and schizophrenia groups than in the controls, while no significant differences were observed in the prevalence of pineal cysts. Although BACS, SCoRS, and SOFAS scores were not associated with pineal morphology, patients with pineal cysts in the schizophrenia group exhibited severe positive psychotic symptoms with rather mild negative symptoms.

CONCLUSION

The present results indicate the potential of pineal atrophy as a vulnerability marker in various stages of psychosis and suggest that pineal cysts influence the clinical subtype of schizophrenia.

Effect of Haloperidol and Risperidone on Serum Melatonin and GAP-43 in Patients with Schizophrenia: A Prospective Cohort Study

OBJECTIVE

Serum melatonin, a biomarker of circadian rhythm, can upregulate Growth-associated protein 43 (GAP-43) which is involved in neural regeneration and plasticity. The present study was conducted to investigate the adequacy of the first-line antipsychotic drugs to improve sleep and circadian rhythm disruptions by assessing the effect of haloperidol and risperidone on serum melatonin and GAP-43 in schizophrenia.

METHODS

In this cohort study, 100 schizophrenic patients were recruited, and clinical evaluations were done using the Positive and Negative Syndrome Scale (PANSS) and the Pittsburgh sleep quality index (PSQI). The patients with predominantly positive symptoms taking haloperidol (Group I) and patients with predominantly negative symptoms taking risperidone (Group II) were admitted and serum melatonin, arylalkylamine N-acetyltransferase, GAP-43 and urinary melatonin were estimated. After 8 weeks, all clinical and biochemical parameters were repeated.

RESULTS

Serum melatonin (2:00 hours) was significantly decreased in both haloperidol (2.42; 95% confidence interval [95% CI]: 0.67-4.17; p = 0.008) and risperidone group (3.40; 95% CI: 0.54-6.25; p = 0.021). Urinary melatonin was significantly decreased in both haloperidol (p = 0.005) and risperidone group (p = 0.014). PSQI score was significantly increased in both haloperidol (p = 0.001) and risperidone group (p = 0.003). Serum GAP-43 was significantly decreased in both haloperidol and risperidone group (p < 0.001). PANSS decreased significantly in both the groups and there was a significant negative correlation between serum melatonin at 2:00 hours and PANSS (r = -0.5) at baseline.

CONCLUSION

Monotherapy with haloperidol and risperidone can achieve symptomatic improvement but cannot improve sleep and circadian rhythm disturbances in schizophrenia.

Schizophrenia-like behavior is not altered by melatonin supplementation in rodents

An emerging area in schizophrenia research focuses on the impact of immunomodulatory drugs such as melatonin, which have played important roles in many biological systems and functions, and appears to be promising. The objective was to evaluate the effect of melatonin on behavioral parameters in an animal model of schizophrenia. For this, Wistar rats were divided and used in two different protocols. In the prevention protocol, the animals received 1 or 10mg/kg of melatonin or water for 14 days, and between the 8th and 14th day they received ketamine or saline. In the reversal protocol, the opposite occurred. On the 14th day, the animals underwent behavioral tests: locomotor activity and prepulse inhibition task. In both protocols, the results revealed that ketamine had effects on locomotor activity and prepulse inhibition, confirming the validity of ketamine construction as a good animal model of schizophrenia. However, at least at the doses used, melatonin was not able to reverse/prevent ketamine damage. More studies are necessary to evaluate the role of melatonin as an adjuvant treatment in psychiatric disorders.

Chronobiology Revisited in Psychiatric Disorders: From a Translational Perspective

OBJECTIVE

Several lines of evidence support a relationship between circadian rhythms disruption in the onset, course, and maintenance of mental disorders. Despite the study of circadian phenotypes promising a decent understanding of the pathophysiologic or etiologic mechanisms of psychiatric entities, several questions still need to be addressed. In this review, we aimed to synthesize the literature investigating chronobiologic theories and their associations with psychiatric entities.

METHODS

The Medline, Embase, PsycInfo, and Scopus databases were comprehensively and systematically searched and articles published between January 1990 and October 2019 were reviewed. Different combinations of the relevant keywords were polled. We first introduced molecular elements and mechanisms of the circadian system to promote a better understanding of the chronobiologic implications of mental disorders. Then, we comprehensively and systematically reviewed circadian system studies in mood disorders, schizophrenia, and anxiety disorders.

RESULTS

Although subject characteristics and study designs vary across studies, current research has demonstrated that circadian pathologies, including genetic and neurohumoral alterations, represent the neural substrates of the pathophysiology of many psychiatric disorders. Impaired HPA-axis function-related glucocorticoid rhythm and disrupted melatonin homeostasis have been prominently demonstrated in schizophrenia and other psychotic disorders, while alterations of molecular expressions of circadian rhythm genes including CLOCK, PER, and CRY have been reported to be involved in the pathogenesis of mood disorders.

CONCLUSION

Further translational work is needed to identify the causal relationship between circadian physiology abnormalities and mental disorders and related psychopathology, and to develop sound pharmacologic interventions.

An Ensemble Approach to Predict Schizophrenia Using Protein Data in the N-methyl-D-Aspartate Receptor (NMDAR) and Tryptophan Catabolic Pathways

In the wake of recent advances in artificial intelligence research, precision psychiatry using machine learning techniques represents a new paradigm. The D-amino acid oxidase (DAO) protein and its interaction partner, the D-amino acid oxidase activator (DAOA, also known as G72) protein, have been implicated as two key proteins in the N-methyl-D-aspartate receptor (NMDAR) pathway for schizophrenia. Another potential biomarker in regard to the etiology of schizophrenia is melatonin in the tryptophan catabolic pathway. To develop an ensemble boosting framework with random undersampling for determining disease status of schizophrenia, we established a prediction approach resulting from the analysis of genomic and demographic variables such as DAO levels, G72 levels, melatonin levels, age, and gender of 355 schizophrenia patients and 86 unrelated healthy individuals in the Taiwanese population. We compared our ensemble boosting framework with other state-of-the-art algorithms such as support vector machine, multilayer feedforward neural networks, logistic regression, random forests, naive Bayes, and C4.5 decision tree. The analysis revealed that the ensemble boosting model with random undersampling [area under the receiver operating characteristic curve (AUC) = 0.9242 ± 0.0652; sensitivity = 0.8580 ± 0.0770; specificity = 0.8594 ± 0.0760] performed maximally among predictive models to infer the complicated relationship between schizophrenia disease status and biomarkers. In addition, we identified a causal link between DAO and G72 protein levels in influencing schizophrenia disease status. The study indicates that the ensemble boosting framework with random undersampling may provide a suitable method to establish a tool for distinguishing schizophrenia patients from healthy controls using molecules in the NMDAR and tryptophan catabolic pathways.

Seasonality in schizophrenia-An analysis of a nationwide registry with 110,735 hospital admissions

Background.

Seasonal patterns in hospitalizations have been observed in various psychiatric disorders, however, it is unclear whether they also exist in schizophrenia. Previous studies found mixed results and those reporting the presence of seasonality differ regarding the characteristics of these patterns. Further, they are inconclusive whether sex is an influencing factor. The aim of this study was therefore to examine if seasonal patterns in hospitalizations can be found in schizophrenia, with special regard to a possible influence of sex, by using a large national dataset.

Methods.

Data on all hospital admissions within Austria due to schizophrenia (F20.0–F20.6) for the time period of 2003–2016 were included. Age standardized monthly variation of hospitalization for women and men was analyzed and the level of significance adjusted for multiple testing.

Results.

The database comprised of 110,735 admissions (59.6% men). Significant seasonal variations were found in the total sample with hospitalization peaks in January and June and a trough in December (p < 0.0001). No significant difference in these patterns was found between women and men with schizophrenia (p < 0.0001).

Conclusion.

Our study shows that schizophrenia-related hospitalizations follow a seasonal pattern in both men and women. The distribution of peaks might be influenced by photoperiod changes which trigger worsening of symptoms and lead to exacerbations in schizophrenia. Further research is necessary to identify underlying factors influencing seasonal patterns and to assess whether a subgroup of patients with schizophrenia is especially vulnerable to the impact of seasonal variations.

Pineal gland and schizophrenia: A systematic review and meta-analysis

Melatonin (MLT), the main hormone of the pineal gland (PG), is assumed to support initiation and maintenance of sleep, and a stable sleep-wake cycle, exerting antioxidative and neuroprotective actions. Evidence demonstrates that sleep and circadian rhythm abnormalities are very common in schizophrenia patients. Some imaging studies suggest structural abnormalities of the PG in these patients as well. We aimed to critically appraise the literature on PG imaging and melatonin secretion in schizophrenia patients, in comparison to matched healthy controls, and to review placebo-controlled trials of add-on exogenous MLT treatment in schizophrenia patients. In this systematic review, twenty-nine studies were included. Meta-analytical evaluation of data was possible only for MLT secretion finding that midnight plasma levels were significantly reduced in individuals with schizophrenia as compared to healthy controls (Hedge`s g = 1.32, p < 0.01). Imaging studies demonstrated greater prevalence of enlarged calcifications (>1 cm) of the PG (2 out of 2 computed tomography studies) and smaller PG volume (2 out of 3 magnetic resonance studies) compared with healthy controls. Anatomic and functional abnormalities of the PG were not associated with duration of illness or with treatment factors, maybe suggesting them to be primary characteristics of the disease and genetically based. Add-on MLT treatment leads to a modest improvement of objective and subjective sleep quality, of metabolic adverse effects of antipsychotics, and of tardive dyskinesia symptoms in schizophrenia patients. It remains to be established whether MLT treatment in prodromal phases of the disease could prevent neurostructural abnormalities.

Evidence for an association of serum melatonin concentrations with recognition and circadian preferences in patients with schizophrenia

Melatonin, a neuro-differentiation factor, may play a role in the neurodevelopmental origins of schizophrenia. Cognitive impairment and decreased melatonin are reported in schizophrenia; however, the relationship between them remains unclear. We hypothesised that patients with schizophrenia would have lower concentrations of circulating melatonin than healthy controls and that melatonin levels would be associated with cognitive impairment. This study included 47 patients with schizophrenia and 40 healthy controls (HC). Serum melatonin concentrations were measured using the enzyme-linked immunosorbent assay. Positive and Negative Syndrome Scales (PANSS), The Morningness-Eveningness Questionnaire (MEQ), Pittsburgh Sleep Quality Index (PSQI), the Stroop and Oktem verbal memory processes (VMPT) tests were applied. Patients with schizophrenia had lower levels of melatonin compared to the HC group (p = 0.016), also after controlling for age, sex, and body mass index (BMI) (p = 0.024). In patients with schizophrenia, melatonin concentrations were associated with higher BMI (rho = 0.34, p = 0.01) and lower MEQ score (rho = -0.29, p = 0.035). The patient sample was split into low and high melatonin categories by using the median melatonin concentration in HC as the cut-off. Patients in the low melatonin group had poorer performance in VMPT-Recognition (p = 0.026) and Stroop-Colour Error (p = 0.032). Notwithstanding its limitations, the findings of this exploratory study suggest that decreased serum melatonin concentrations observed in schizophrenia might also be associated with cognitive impairment and circadian preferences. Future studies are required to investigate the role of melatonergic pathways in patients with schizophrenia.

Reduced pineal gland volume across the stages of schizophrenia

A few magnetic resonance imaging (MRI) studies reported reduced pineal gland volume in chronic schizophrenia (Sz), implicating the involvement of melatonin in the pathophysiology of the illness. However, it is not known whether this abnormality, if present, exists at the early illness stages and/or develops progressively over the course of the illness. This MRI study examined pineal gland volume in 64 patients with first-episode schizophrenia (FESz), 40 patients with chronic Sz, 22 individuals with at-risk mental state (ARMS), and 84 healthy controls. Longitudinal changes in pineal volume (mean inter-scan interval = 2.5 ± 0.7 years) were also examined in a subsample of 23 FESz, 16 chronic Sz, and 21 healthy subjects. In the cross-sectional comparison, the ARMS, FESz, and chronic Sz groups had significantly smaller pineal volume to the same degree as compared with healthy controls. A longitudinal comparison demonstrated that pineal volume did not change over time in any group. There was no association between pineal volume and clinical variables (e.g., symptom severity, medication) in the ARMS and Sz groups. The results suggest that a smaller pineal gland may be a static vulnerability marker of Sz, which probably reflects an early neurodevelopmental abnormality.

Microbes and Monoamines: Potential Neuropsychiatric Consequences of Dysbiosis

From an evolutionary perspective, the genes of enteric microbes transmitted reliably across generations are nearly as much a part of the human organism as our own genes. Disruption of the microbiome leading to extinction of key 'heirloom' taxa can deprive individuals of metabolic pathways that have been present in their ancestors for millennia. Some of these pathways support essential synthesis and toxin clearance processes, including the generation of blood-brain barrier-crossing metabolic products crucial for normal brain function. Here, we discuss three such pathways: endogenous benzodiazepine synthesis, production of queuine/queuosine, and excretion of dietary mercury. Among them, these pathways have the potential to impact systems relevant to a wide range of neurodevelopmental and psychiatric conditions including autism, depression, anxiety, and schizophrenia.

The effects of melatonin supplementation on blood pressure in patients with metabolic disorders: a systematic review and meta-analysis of randomized controlled trials

The current systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to evaluate the potential effect of melatonin supplementation on blood pressure in patients with metabolic disorders. The following databases were searched until June 2018: PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials. Two reviewers independently assessed the eligibility of retrieved studies, extracted data from included trials, and evaluated the risk of bias of included studies. Statistical heterogeneity was tested using Cochran's Q test and I-square (I²) statistic. Data were pooled using random-effect models and standardized mean difference (SMD) was considered as the effect size. Eight RCTs, out of 743 potential citations, were eligible to be included in the current meta-analysis. The pooled findings indicated a significant reduction in systolic (SBP) (SMD = -0.87; 95% CI, -1.36, -0.38; P = 0.001; I²: 84.3) and diastolic blood pressure (DBP) (SMD = -0.85; 95% CI, -1.20, -0.51; P = 0.001; I²: 68.7) following melatonin supplementation in individuals with metabolic disorders. In summary, the current meta-analysis demonstrated that melatonin supplementation significantly decreased SBP and DBP in patients with metabolic disorders. Additional prospective studies are recommended using higher supplementation doses and longer intervention periods to confirm our findings.

Nutritional modulation of the intestinal microbiota; future opportunities for the prevention and treatment of neuroimmune and neuroinflammatory disease

The gut-brain axis refers to the bidirectional communication between the enteric nervous system and the central nervous system. Mounting evidence supports the premise that the intestinal microbiota plays a pivotal role in its function and has led to the more common and perhaps more accurate term gut-microbiota-brain axis. Numerous studies have identified associations between an altered microbiome and neuroimmune and neuroinflammatory diseases. In most cases, it is unknown if these associations are cause or effect; notwithstanding, maintaining or restoring homeostasis of the microbiota may represent future opportunities when treating or preventing these diseases. In recent years, several studies have identified the diet as a primary contributing factor in shaping the composition of the gut microbiota and, in turn, the mucosal and systemic immune systems. In this review, we will discuss the potential opportunities and challenges with respect to modifying and shaping the microbiota through diet and nutrition in order to treat or prevent neuroimmune and neuroinflammatory disease.

Reciprocal Interactions of Mitochondria and the Neuroimmunoendocrine System in Neurodegenerative Disorders: An Important Role for Melatonin Regulation

Structural and functional alterations of mitochondria are intimately linked to a wide array of medical conditions. Many factors are involved in the regulation of mitochondrial function, including cytokines, chaperones, chemokines, neurosteroids, and ubiquitins. The role of diffusely located cells of the neuroendocrine system, including biogenic amines and peptide hormones, in the management of mitochondrial function, as well as the role of altered mitochondrial function in the regulation of these cells and system, is an area of intense investigation. The current article looks at the interactions among the cells of the neuronal-glia, immune and endocrine systems, namely the diffuse neuroimmunoendocrine system (DNIES), and how DNIES interacts with mitochondrial function. Whilst changes in DNIES can impact on mitochondrial function, local, and systemic alterations in mitochondrial function can alter the component systems of DNIES and their interactions. This has etiological, course, and treatment implications for a wide range of medical conditions, including neurodegenerative disorders. Available data on the role of melatonin in these interactions, at cellular and system levels, are reviewed, with directions for future research indicated.

Breastfeeding and the gut-brain axis: is there a role for melatonin?

The benefits of breastfeeding over formula feed are widely appreciated. However, for many mothers breastfeeding is not possible, highlighting the need for a significant improvement in the contents of formula feed. In this article, the overlooked role of melatonin and the melatonergic pathways in breast milk and in the regulation of wider breast milk components are reviewed. There is a growing appreciation that the benefits of breastfeeding are mediated by its effects in the infant gut, with consequences for the development of the gut-brain axis and the immune system. The melatonergic pathways are intimately associated with highly researched processes in the gut, gut microbiome and gut-brain axis. As the melatonergic pathways are dependent on the levels of serotonin availability as a necessary precursor, decreased melatonin is linked to depression and depression-associated disorders. The association of breastfeeding and the gut-brain axis with a host of medical conditions may be mediated by their regulation of processes that modulate depression susceptibility. The biological underpinnings of depression include increased levels of pro-inflammatory cytokines, oxidative stress, kynurenine pathway activity and dysregulation of the hypothalamic-pituitary adrenal axis, all of which can decrease melatonergic pathway activity. The inclusion of the melatonergic pathways in the biological interactions of breast milk and gut development has significant theoretical and treatment implications, as well as being important to the prevention of a host of infant-, child- and adult-onset medical conditions.

Antipsychotic-induced Tardive dyskinesia: from biological basis to clinical management

INTRODUCTION

Tardive dyskinesia (TD) is a chronic and disabling movement disorder with a complex pathophysiological basis. A significant percentage of patients does not receive correct diagnosis, resulting in delayed or inaccurate treatment and poor outcome. Therefore, there is a critical need for prompt recognition, implementation of efficacious treatment regimens and long-term follow up of patients with TD. Areas covered: The current paper provides an overview of emerging data concerning proposed pathophysiology theories, epidemiology, risk factors, and therapeutic strategies for TD. Expert commentary: Despite considerable research efforts, TD remains a challenge in the treatment of psychosis as the available strategies remain sub-optimal. The best scenario will always be the prophylaxis or prevention of TD, which entails limiting the use of antipsychotics.

Melatonin attenuates behavioural deficits and reduces brain oxidative stress in a rodent model of schizophrenia

Melatonin is a neurohormone that is linked to the aetiopathogenesis of schizophrenia. The aim of this study was to assess the potentials of oral melatonin supplement in the management of induced schizophrenia-like behavioural and brain oxidative status changes, using an animal model. The relative degrees of modulation of ketamine-induced behaviours by haloperidol, olanzapine or melatonin were assessed in the open-field, Y-maze, elevated plus maze and the social interaction tests. 12-week old, male mice were assigned to six groups of ten each (n=10). They were pretreated with daily intraperitoneal ketamine at 15mg/kg (except vehicle) for 10days, before commencement of 14day treatment with standard drug (haloperidol or olanzapine) or melatonin. Ketamine injection also continued alongside melatonin or standard drugs administration for the duration of treatment. Melatonin, haloperidol and olanzapine were administered by gavage. Treatments were given daily, and behaviours assessed on days 11 and 24. On day 24, animals were sacrificed and whole brain homogenates used for the estimation of glutathione, nitric oxide and malondialdehyde levels. Ketamine injection increased open-field behaviours; while it decreased working-memory, social-interaction and glutathione activity. Nitric oxide and malondialdehyde levels also increased after ketamine injection. Administration of melatonin was associated with variable degrees of reversal of these effects. In conclusion, melatonin may have the potential of a possible therapeutic agent and/or adjunct in the management of schizophrenia.

Neurocognitive performance, subjective well-being, and psychosocial functioning after benzodiazepine withdrawal in patients with schizophrenia or bipolar disorder: a randomized clinical trial of add-on melatonin versus placebo

Chronic benzodiazepine use is common in patients with mental illness and is associated with cognitive impairment. It is unclear whether benzodiazepine-induced cognitive impairment is reversible. Amelioration of cognitive dysfunction may be facilitated during benzodiazepine tapering by add-on melatonin due to its anti-inflammatory and neuroprotective properties. We examined how melatonin and benzodiazepine withdrawal affect cognition, subjective well-being, and psychosocial functioning. Eighty patients with schizophrenia or bipolar disorder were randomized to add-on treatment once daily with either prolonged-release melatonin or placebo in a 24-week, double-blind clinical trial. All participants gradually tapered usual benzodiazepine dosage in a closely monitored treatment setting. We used the Brief Assessment of Cognition in Schizophrenia (BACS) to assess neurocognitive performance with additional assessments of subjective well-being and psychosocial functioning. BACS composite and subscale scores (except motor speed) significantly improved in parallel with benzodiazepine dose reduction, but there was no additional effect of melatonin. Cognitive performance was still markedly impaired post-tapering compared with normative data. Neither benzodiazepine withdrawal nor treatment group affected subjective well-being or psychosocial functioning. In conclusion, add-on melatonin does not seem to affect cognition, well-being, or psychosocial functioning in patients with severe mental illness. The observed improvement in cognitive performance could not be distinguished from retest effects, which may in turn have been facilitated by the benzodiazepine tapering.

The association between sleep dysfunction and psychosis-like experiences among college students

Sleep problems are prominent and pervasive clinical issues experienced by many people with psychotic disorders, often causing distress and functional impairment. Sleep problems are also related to psychosis-like experiences (PLE; non-diagnosable phenomenon such as transient perceptual disturbances, unusual thoughts, periodic suspiciousness) in epidemiological studies. Prior studies in this field have used brief measures that precluded the ability to test (1) whether risk for psychosis-like experiences are related to specific sub-types of sleep disturbance, and (2) whether sleep disturbance is specifically related to clinically significant (i.e., distressing) psychosis-like experiences. The current project examined the relation between specific sleep issues, and PLEs and distress associated with PLEs, in a college sample. Participants (N=420) completed the Prodromal Questionnaire-Brief (PQ-B), which assesses PLEs and associated distress, and the Iowa Sleep Disturbances Inventory - extended version (ISDI-E), which assesses thirteen separate disturbed sleep domains. Symptoms of fragmented sleep, sleep hallucinations, and night anxiety significantly correlated with PLEs, and several sleep domains were significantly associated with PLE-related distress.

Reversal of schizophrenia-like symptoms and immune alterations in mice by immunomodulatory drugs

Immune dysregulation observed in schizophrenia alters tryptophan metabolism. Tryptophan metabolism is triggered by indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO). Tryptophan is converted to quinolinic acid, a potent neurotoxin, and to kynurenic acid, an NMDA antagonist. 1-Methyl-D-tryptophan (MDT) inhibits IDO. Melatonin is metabolized by IDO while inhibiting TDO. We evaluated the reversal of ketamine-induced schizophrenia-like behavioral and neurochemical alterations in mice by the administration of MDT (20 or 40 mg/kg, i.p.) or melatonin (15 mg/kg, per os). Oxidative stress and inflammatory alterations, i.e. myeloperoxidase activity (MPO), reduced glutathione (GSH), lipid peroxidation (LPO) and interleukin (IL)-4 and IL-6 were measured in the prefrontal cortex (PFC), hippocampus and striatum. Risperidone was used as standard antipsychotic. Ketamine triggered positive- (PPI deficits and hyperlocomotion), cognitive- (working memory deficits) and negative (social interaction deficits) schizophrenia-like symptoms. These symptoms were accompanied by increased MPO activity, decreased GSH and increased LPO in all brain areas and increments in hippocampal IL-4 and IL-6. MDT and melatonin reversed all ketamine-induced behavioral alterations. Risperidone did not reverse working memory deficits. MDT and melatonin reversed alterations in MPO activity and GSH levels. LP was reversed only by melatonin and risperidone. Risperidone could not reverse MPO alterations in the PFC and striatum. All drugs reversed the alterations in IL-4 and IL-6. The hippocampus and striatum of ketamine+melatonin-treated animals had lower levels of IL-6. Our findings provide further preclinical evidence that immune-inflammatory and oxidative pathways are involved in schizophrenia and that targeting these pathways is a valid treatment option in schizophrenia.

Prolonged-release melatonin versus placebo for benzodiazepine discontinuation in patients with schizophrenia or bipolar disorder: A randomised, placebo-controlled, blinded trial

OBJECTIVES

We assessed if prolonged-release melatonin can facilitate withdrawal of long-term benzodiazepine usage in patients with schizophrenia or bipolar disorder.

METHODS

Randomised, placebo-controlled, blinded, parallel superiority trial of 24 weeks duration. Participants were randomised to prolonged-release melatonin 2 mg daily versus matching placebo and were continuously guided to gradually reduce their usual benzodiazepine dosage. The primary outcome was mean benzodiazepine daily dosage at 24 weeks. Secondary outcomes included pattern of benzodiazepine dosage over time, benzodiazepine cessation proportion, and benzodiazepine withdrawal symptoms.

RESULTS

In total, 86 patients (21-74 years) were enrolled: 42 were randomised to melatonin versus 44 to placebo. We found no significant effect of melatonin on mean benzodiazepine dosage at 24 weeks (melatonin group 8.01 mg versus placebo group 5.72 mg diazepam equivalents; difference between means -2.29; 95% CI -5.78 to 1.21; P = 0.20). Benzodiazepine cessation proportion was 38.1% (16/42) in the melatonin group versus 47.7% (21/44) in the placebo group (OR 0.64; 95% CI 0.26 to 1.56; P = 0.32). Prolonged-release melatonin had no effect on benzodiazepine withdrawal symptoms.

CONCLUSIONS

Benzodiazepine dosage was comparably low between the groups after 24 weeks of guided gradual dose reduction. In this context, prolonged-release melatonin did not seem to further facilitate benzodiazepine discontinuation.

Objective and subjective sleep quality: Melatonin versus placebo add-on treatment in patients with schizophrenia or bipolar disorder withdrawing from long-term benzodiazepine use

Benzodiazepines are frequently long-term prescribed for the treatment of patients with severe mental illness. This prescribing practice is problematic because of well-described side effects including risk of dependence. We examined the efficacy of prolonged-release melatonin on objective and subjective sleep quality during benzodiazepine discontinuation and whether sleep variables were associated with benzodiazepine withdrawal. Eligible patients included adults with a diagnosis of schizophrenia, schizoaffective disorder, or bipolar disorder and long-term use of benzodiazepines in combination with antipsychotics. All participants gradually tapered the use of benzodiazepines after randomization to add-on treatment with melatonin versus placebo. Here we report a subsample of 23 patients undergoing sleep recordings (one-night polysomnography) and 55 patients participating in subjective sleep quality ratings. Melatonin had no effect on objective sleep efficiency, but significantly improved self-reported sleep quality. Reduced benzodiazepine dosage at the 24-week follow-up was associated with a significantly decreased proportion of stage 2 sleep. These results indicate that prolonged-release melatonin has some efficacy for self-reported sleep quality after gradual benzodiazepine dose reduction, and that benzodiazepine discontinuation is not associated with rebound insomnia in medicated patients with severe mental illness. However, these findings were limited by a small sample size and a low retention rate.

Sleep and inflammatory markers in different psychiatric disorders

Many psychiatric disorders, like schizophrenia, affective disorders, addictions and different forms of dementia are associated with sleep disturbances. In the etiology and course of those diseases inflammatory processes are regarded to be an increasingly important factor. They are also a frequently discussed element of the pathology of sleep. In this literature review reports on correlations between poor sleep and inflammatory responses in various psychiatric conditions are discussed. The link between schizophrenia, affective disorders and inflammatory cytokines is a complex phenomenon, which has been already confirmed in a number of studies. However, the presence of sleep deficits in those conditions, being a common symptom of depression and psychoses, can be an additional factor having a considerable impact on the immunological processes in mental illnesses. In the analyzed data, a number of studies are presented describing the role of inflammatory markers in sleep disturbances and psychopathological symptoms of affective, psychotic, neurogenerative and other disorders. Also attention is drawn to possible implications for their treatment. Efforts to use, e.g., anti-inflammatory agents in psychiatry in the context of their impact on sleep are reported. The aspect of inflammatory markers in the role of sleep deprivation as the treatment method in major depressive disorder is also discussed. A general conclusion is drawn that the improvement of sleep quality plays a crucial role in the care for psychiatric patients.

The role of sleep dysfunction in the occurrence of delusions and hallucinations: A systematic review

BACKGROUND

Sleep dysfunction is extremely common in patients with schizophrenia. Recent research indicates that sleep dysfunction may contribute to psychotic experiences such as delusions and hallucinations.

OBJECTIVES

The review aims to evaluate the evidence for a relationship between sleep dysfunction and individual psychotic experiences, make links between the theoretical understanding of each, and highlight areas for future research.

METHOD

A systematic search was conducted to identify studies investigating sleep and psychotic experiences across clinical and non-clinical populations.

RESULTS

66 papers were identified. This literature robustly supports the co-occurrence of sleep dysfunction and psychotic experiences, particularly insomnia with paranoia. Sleep dysfunction predicting subsequent psychotic experiences receives support from epidemiological surveys, research on the transition to psychosis, and relapse studies. There is also evidence that reducing sleep elicits psychotic experiences in non-clinical individuals, and that improving sleep in individuals with psychosis may lessen psychotic experiences. Anxiety and depression consistently arise as (partial) mediators of the sleep and psychosis relationship.

CONCLUSION

Studies are needed that: determine the types of sleep dysfunction linked to individual psychotic experiences; establish a causal connection between sleep and psychotic experiences; and assess treatments for sleep dysfunction in patients with non-affective psychotic disorders such as schizophrenia.

Fetal programming of schizophrenia: select mechanisms

Mounting evidence indicates that schizophrenia is associated with adverse intrauterine experiences. An adverse or suboptimal fetal environment can cause irreversible changes in brain that can subsequently exert long-lasting effects through resetting a diverse array of biological systems including endocrine, immune and nervous. It is evident from animal and imaging studies that subtle variations in the intrauterine environment can cause recognizable differences in brain structure and cognitive functions in the offspring. A wide variety of environmental factors may play a role in precipitating the emergent developmental dysregulation and the consequent evolution of psychiatric traits in early adulthood by inducing inflammatory, oxidative and nitrosative stress (IO&NS) pathways, mitochondrial dysfunction, apoptosis, and epigenetic dysregulation. However, the precise mechanisms behind such relationships and the specificity of the risk factors for schizophrenia remain exploratory. Considering the paucity of knowledge on fetal programming of schizophrenia, it is timely to consolidate the recent advances in the field and put forward an integrated overview of the mechanisms associated with fetal origin of schizophrenia.

Bipolar disorder: role of immune-inflammatory cytokines, oxidative and nitrosative stress and tryptophan catabolites

Bipolar disorder (BD) is a complex disorder with a range of presentations. BD is defined by the presentation of symptoms of mania or depression, with classification dependent on patient/family reports and behavioural observations. Recent work has investigated the biological underpinnings of BD, highlighting the role played by increased immune-inflammatory activity, which is readily indicated by changes in pro-inflammatory cytokines or signalling, both centrally and systemically, e.g. increased interleukin-6 trans-signalling. Here, we review the recent data on immune-inflammatory pathways and cytokine changes in BD. Such changes are intimately linked to changes in oxidative and nitrosative stress (O&NS) and neuroregulatory tryptophan catabolites (TRYCATs), both centrally and peripherally. TRYCATs take tryptophan away from serotonin, N-acetylserotonin and melatonin synthesis, driving it down the TRYCAT pathway, predominantly as a result of the pro-inflammatory cytokine induction of indoleamine 2,3-dioxygenase. This has led to an emerging biological perspective on the aetiology, course and treatment of BD. Such data also better integrates the numerous comorbidities associated with BD, including addiction, cardiovascular disorders and increased reporting of pain. Immune-inflammatory, O&NS and TRYCAT pathways are also likely to be relevant biological underpinnings to the significant decrease in life expectancy in BD.

Nutritional interventions for the adjunctive treatment of schizophrenia: a brief review

Schizophrenia is a chronic condition that impacts significantly not only on the individual and family, but the disorder also has wider consequences for society in terms of significant costs to the economy. This highly prevalent condition affects approximately 1% of the worldwide population, yet there are few therapeutic options. The predominant treatment strategy for schizophrenia is anti-psychotic medication (with or without additional talking therapy) even though this approach lacks efficacy in managing the negative symptoms of the condition, is not effective in one-third of the patient group and the side effects of the medication can be severe and debilitating. In recent years, a number of pathophysiological processes have been identified in groups of people with schizophrenia including oxidative stress, one-carbon metabolism and immune-mediated responses. A number of studies have shown that these altered physiological mechanisms can be ameliorated by nutritional interventions in some individuals with schizophrenia. This review briefly describes the aforementioned processes and outlines research that has investigated the utility of nutritional approaches as an adjunct to anti-psychotic medication including antioxidant and vitamin B supplementation, neuroprotective and anti-inflammatory nutrients and exclusion diets. Whilst none of these interventions provides a ‘one-size-fits-all’ therapeutic solution, we suggest that a personalised approach warrants research attention as there is growing agreement that schizophrenia is a spectrum disorder that develops from the interplay between environmental and genetic factors.

Augmentation of clozapine with agomelatine in partial-responder schizophrenia: a 16-week, open-label, uncontrolled pilot study

The present 16-week open-label uncontrolled trial was aimed to explore the efficacy of adjunctive agomelatine on clinical symptoms and cognitive functioning in 20 schizophrenia patients showing partial response (Brief Psychiatric Rating Scale, mean [SD] baseline total score = 37.5 [6.6]) to clozapine monotherapy at the highest tolerated dosage. The results obtained evidenced that agomelatine at a dosage of 50 mg/d was associated with score reduction in all Positive and Negative Syndrome Scale domains (positive, P = 0.011 and Cohen d = 0.7; negative, P < 0.0001 and Cohen d = 1.1; psychopathology, P = 0.001 and Cohen d = 0.9) and total score (P = 0.001, Cohen d = 1.2), depressive (Calgary Depression Scale for Schizophrenia, P = 0.013 and Cohen d = 0.6), and overall clinical symptoms (Brief Psychiatric Rating Scale, P = 0.001 and Cohen d = 0.6 ); moreover, improved performances on Stroop task (P = 0.006, Cohen d = 0.7) and Wisconsin Card Sorting Test "perseverative errors" (P = 0.033, Cohen d = 0.3) were observed. The favorable effect of agomelatine on clinical and cognitive symptoms was encouraging, and more research is needed to better identify subgroups of patients who are partially responsive to clozapine monotherapy in which agomelatine augmentation may be of benefit.

ASMT gene expression correlates with cognitive impairment in patients with recurrent depressive disorder

BACKGROUND

Recurrent depressive disorder is a multifactorial disease; one of the typical features is cognitive impairment. The purpose of this study was analysis of ASMT gene expression both on mRNA and protein levels in patients with recurrent depressive disorder (rDD) and assessment of the relationship between plasma level of ASMT protein, gene expression on mRNA level, and cognitive performance.

MATERIAL AND METHODS

The study included 236 subjects: patients with rDD (n=131) and healthy subjects (n=105, CG). Cognitive function assessment was based on: Trail Making Test, The Stroop Test, Verbal Fluency Test (VFT), and Auditory Verbal Learning Test (AVLT).

RESULTS

Both mRNA and protein expression levels of ASMT gene were significantly higher in healthy subjects when compared to rDD. The average ASMT mRNA expression level measured for the entire group was M=0.21 (SD=0.09), and the protein level was M=12.84 (SD=3.29). In patients with rDD, statistically significant correlations occurred between both mRNA and protein expression levels and part A of the TMT (negative correlation) and verbal fluency test (positive correlation). In the group CG, there was no statistically significant association between the analyzed variables. In the entire group there was a statistically significant correlation between both ASMT mRNA and protein expression levels and all the neuropsychological tests used in the survey.

CONCLUSIONS

1. Our study confirms previous results showing decreased mRNA and protein expression levels of ASMT gene in depression. 2. Our data suggest a relationship between decreased mRNA and protein expression levels of ASMT gene and cognitive impairment.

Melatonin attenuates antipsychotic metabolic effects: an eight-week randomized, double-blind, parallel-group, placebo-controlled clinical trial

OBJECTIVE

Second-generation antipsychotics (SGAs) are among the first-line treatments for bipolar disorder and schizophrenia, but have a tendency to generate metabolic disturbances. These features resemble a metabolic syndrome for which a central autonomic imbalance has been proposed that may originate from the hypothalamic suprachiasmatic nuclei. In a clinical trial, we hypothesized that melatonin, a hormone that regulates the suprachiasmatic nucleus, could attenuate SGA-induced adverse metabolic effects.

METHODS

In an eight-week, double-blind, randomized, placebo-controlled, parallel-group clinical trial, we evaluated the metabolic effect of melatonin in SGA-treated patients in terms of weight, blood pressure, lipid, glucose, body composition, and anthropometric measures. A total of 44 patients treated with SGAs, 20 with bipolar disorder and 24 with schizophrenia, randomly received placebo (n = 24) or melatonin 5 mg (n = 20).

RESULTS

The melatonin group showed a decrease in diastolic blood pressure (5.1 versus 1.1 mmHg for placebo, p = 0.003) and attenuated weight gain (1.5 versus 2.2 kg for placebo, F = 4.512, p = 0.040) compared to the placebo group. The strong beneficial metabolic effects of melatonin in comparison to placebo on fat mass (0.2 versus 2.7 kg, respectively, p = 0.032) and diastolic blood pressure (5.7 versus 5.5 mmHg, respectively, p = 0.001) were observed in the bipolar disorder and not in the schizophrenia group. No adverse events were reported.

CONCLUSIONS

Our results show that melatonin is effective in attenuating SGAs' adverse metabolic effects, particularly in bipolar disorder. The clinical findings allow us to propose that SGAs may disturb a centrally mediated metabolic balance that causes adverse metabolic effects and that nightly administration of melatonin helps to restore. Melatonin could become a safe and cost-effective therapeutic option to attenuate or prevent SGA metabolic effects.

Melatonin for prevention of metabolic side-effects of olanzapine in patients with first-episode schizophrenia: randomized double-blind placebo-controlled study

We aimed to determine the efficacy of melatonin 3 mg/day in prevention of olanzapine-induced metabolic side-effects. In a randomized double-blind placebo-controlled study, 48 patients with first-episode schizophrenia who were eligible for olanzapine treatment, were randomly assigned to olanzapine plus either melatonin 3 mg/day or matched placebo for eight weeks. Anthropometric and metabolic parameters as well as psychiatric symptoms using The Positive and Negative Syndrome Scale (PANSS) were assessed at baseline, week 4, and 8. Primary outcome measure was the change from baseline in weight at week 8. Data were analyzed using t-test, Mann-Whitney U test, and mixed-effects model. Thirty-six patients had at least one post-baseline measurement. At week eight, melatonin was associated with significantly less weight gain [mean difference (MD) = 3.2 kg, P = 0.023], increase in waist circumference [MD = 2.83 cm, P = 0.041] and triglyceride concentration [MD = 62 mg/dl, P = 0.090 (nearly significant)] than the placebo. Changes in cholesterol, insulin, and blood sugar concentrations did not differ significantly between the two groups. Patients in the melatonin group experienced significantly more reduction in their PANSS scores [MD = 12.9 points, P = 0.014] than the placebo group. No serious adverse events were reported. To summarize, in patients treated with olanzapine, short-term melatonin treatment attenuates weight gain, abdominal obesity, and hypertriglyceridemia. It might also provide additional benefit for treatment of psychosis. The study was registered in the ClinicalTrials.gov (

REGISTRATION NUMBER

NCT01593774).

Effects of melatonin on prepulse inhibition, habituation and sensitization of the human startle reflex in healthy volunteers

Prepulse inhibition of the startle reflex (PPI) is an operational measure of sensorimotor gating, which is demonstrated to be impaired in patients with schizophrenia. In addition, a disruption of the circadian rhythm together with blunted melatonin secretion is regularly found in patients with schizophrenia and it is theorized that these may contribute to their attentional deficits. The aim of this study was to assess the effects of acute melatonin on healthy human sensorimotor gating. Twenty-one healthy male volunteers were administered melatonin or placebo after which their levels of PPI were assessed. Melatonin significantly reduced startle magnitude and ratings of alertness, but did not influence PPI, nor sensitization and habituation. However, when taking baseline scores in consideration, melatonin significantly increased PPI in low scoring individuals while significantly decreasing it in high scoring individuals in low intensity prepulse trialtypes only. In addition, subjective ratings of alertness correlated with PPI. The results suggest that melatonin has only minor influences on sensorimotor gating, habituation and sensitization of the startle reflex of healthy males. The data do indicate a relationship between alertness and PPI. Further research examining the effects of melatonin on these processes in patients with schizophrenia is warranted.

Mitochondrial dysfunction in psychiatric and neurological diseases: cause(s), consequence(s), and implications of antioxidant therapy

Mitochondrial dysfunction is at the base of development and progression of several psychiatric and neurologic diseases with different etiologies. MtDNA/nDNA mutational damage, failure of endogenous antioxidant defenses, hormonal malfunction, altered membrane permeability, metabolic dysregulation, disruption of calcium buffering capacity and ageing have been found to be the root causes of mitochondrial dysfunction in psychatric and neurodegenerative diseases. However, the overall consequences of mitochondrial dysfunction are only limited to increase in oxidative/nitrosative stress and cellular energy crises. Thus far, extensive efforts have been made to improve mitochondrial function through specific cause-dependent antioxidant therapy. However, owing to complex genetic and interlinked causes of mitochondrial dysfunction, it has not been possible to achieve any common, unique supportive antioxidant therapeutic strategy for the treatment of psychiatric and neurologic diseases. Hence, we propose an antioxidant therapeutic strategy for management of consequences of mitochondrial dysfunction in psychiatric and neurologic diseases. It is expected that this will not only reduces oxidative stress, but also promote anaerobic energy production.

Schizophrenia is primed for an increased expression of depression through activation of immuno-inflammatory, oxidative and nitrosative stress, and tryptophan catabolite pathways

Schizophrenia and depression are two common and debilitating psychiatric conditions. Up to 61% of schizophrenic patients have comorbid clinical depression, often undiagnosed. Both share significant overlaps in underlying biological processes, which are relevant to the course and treatment of both conditions. Shared processes include changes in cell-mediated immune and inflammatory pathways, e.g. increased levels of pro-inflammatory cytokines and a Th1 response; activation of oxidative and nitrosative stress (O&NS) pathways, e.g. increased lipid peroxidation, damage to proteins and DNA; decreased antioxidant levels, e.g. lowered coenzyme Q10, vitamin E, glutathione and melatonin levels; autoimmune responses; and activation of the tryptophan catabolite (TRYCAT) pathway through induction of indoleamine-2,3-dioxygenase. Both show cognitive and neurostructural evidence of a neuroprogressive process. Here we review the interlinked nature of these biological processes, suggesting that schizophrenia is immunologically primed for an increased expression of depression. Such a conceptualization explains, and incorporates, many of the current perspectives on the nature of schizophrenia and depression, and has implications for the nature of classification and treatment of both disorders. An early developmental etiology to schizophrenia, driven by maternal infection, with subsequent impact on offspring immuno-inflammatory responses, creates alterations in the immune pathways, which although priming for depression, also differentiates the two disorders.

Putative neuroprotective agents in neuropsychiatric disorders

In many individuals with major neuropsychiatric disorders including depression, bipolar disorder and schizophrenia, their disease characteristics are consistent with a neuroprogressive illness. This includes progressive structural brain changes, cognitive and functional decline, poorer treatment response and an increasing vulnerability to relapse with chronicity. The underlying molecular mechanisms of neuroprogression are thought to include neurotrophins and regulation of neurogenesis and apoptosis, neurotransmitters, inflammatory, oxidative and nitrosative stress, mitochondrial dysfunction, cortisol and the hypothalamic-pituitary-adrenal axis, and epigenetic influences. Knowledge of the involvement of each of these pathways implies that specific agents that act on some or multiple of these pathways may thus block this cascade and have neuroprotective properties. This paper reviews the potential of the most promising of these agents, including lithium and other known psychotropics, aspirin, minocycline, statins, N-acetylcysteine, leptin and melatonin. These agents are putative neuroprotective agents for schizophrenia and mood disorders.