Dopamine dysregulation syndrome: implications for a dopamine hypothesis of bipolar disorder

Machine learning-based differentiation of schizophrenia and bipolar disorder using multiscale fuzzy entropy and relative power from resting-state EEG

Schizophrenia (SZ) and bipolar disorder (BD) pose diagnostic challenges due to overlapping clinical symptoms and genetic factors, often resulting in misdiagnosis and suboptimal treatment outcomes. This study aimed to identify EEG-based biomarkers that can differentiate SZ from BD using multiscale fuzzy entropy (MFE) and relative power (RP) analyses and to evaluate their diagnostic utility using machine learning. EEG data were collected from 65 patients with SZ and 49 patients with BD under resting-state conditions. The MFE and RP were calculated for the bilateral frontal, central, and parietal regions using 30 s EEG segments. For MFE, the band-scale fuzzy entropy (FuzzyEn) was determined across the theta, alpha, beta, and gamma bands based on simulation results demonstrating an inverse relationship between scale factors and frequency components. RP was derived by segmenting the EEG data into 2 s intervals with a 500 ms moving window. A support vector machine (SVM) was used to differentiate between patients with SZ and BD based on band-scale FuzzyEn and RP. The SVM classifier achieved an accuracy of 78.94%, a sensitivity of 81.53%, and a specificity of 75.51%. Patients with SZ showed higher theta-scale FuzzyEn in the right frontal, left central, and bilateral parietal regions; higher alpha-scale FuzzyEn in the right parietal region; and increased theta power in the bilateral frontal, central, and right parietal regions. These differences remained robust after controlling for medication effects. These findings demonstrate the potential of combining MFE, RP, and machine learning to differentiate between SZ and BD, contributing to improved diagnostic precision in psychiatric disorders.

Linking Mitochondrial Dysfunction, Neurotransmitter, and Neural Network Abnormalities and Mania: Elucidating Neurobiological Mechanisms of the Therapeutic Effect of the Ketogenic Diet in Bipolar Disorder

There is growing interest in the ketogenic diet as a treatment for bipolar disorder (BD), and there are promising anecdotal and small case study reports of efficacy. However, the neurobiological mechanisms by which diet-induced ketosis might ameliorate BD symptoms remain to be determined, particularly in manic and hypomanic states-defining features of BD. Identifying these mechanisms will provide new markers to guide personalized interventions and provide targets for novel treatment developments for individuals with BD. In this critical review, we describe recent findings highlighting 2 types of neurobiological abnormalities in BD: 1) mitochondrial dysfunction and 2) neurotransmitter and neural network functional abnormalities. We link these abnormalities to mania/hypomania and depression in BD and then describe the biological underpinnings by which the ketogenic diet may have a beneficial effect in individuals with BD. We end the review by describing approaches that can be employed in future studies to elucidate the neurobiology that underlies the therapeutic effect of the ketogenic diet in BD. Doing this may provide marker predictors to identify individuals who will respond well to the ketogenic diet, as well as offer neural targets for novel treatment developments for BD.

Risk of subsequent Parkinson's disease among patients with bipolar disorder or major depression: A nationwide longitudinal study in Taiwan

AIM

Bipolar disorder (BD) and major depression have been associated with an increased risk of developing Parkinson's disease (PD); however, few studies have directly compared the risk of PD development between patients with BD and major depression while considering relevant risk factors and psychotropic medications.

METHODS

Using the Taiwan National Health Insurance Research Database, 21,186 patients with BD, 21,188 patients with major depression, and 42,374 controls were enrolled between 2001 and 2009, and followed until the end of 2011. Individuals who developed PD during the follow-up period were identified. Cox regression models were used to analyze the hazard ratio (HR) of developing PD, adjusting for demographic factors, comorbidities, and psychotropic medication usage.

RESULTS

Both patients with BD [HR 8.63, 95% confidence interval (CI) 6.35-11.72] and those with major depression (HR 5.68, 95% CI 4.15-7.78) had an elevated risk of subsequent PD compared to the controls. Patients with BD were associated with a 51% increased risk of subsequent PD compared with patients with major depression. Long-term treatment with antiepileptic mood stabilizers was associated with increased PD risk among patients with late-onset BD and high Charlson comorbidity index scores. Lithium was not associated with an increased PD risk.

CONCLUSIONS

The study highlights an elevated PD risk in patients with BD and major depression compared to the controls, with BD patients at highest risk. Further research is needed to elucidate the complex interplay between psychotropic medications and neurodegenerative processes in BD, aiming to optimize therapeutic strategies and improve patient outcomes.

Vitamin D3 and zinc supplements augment the antimanic efficacy of lithium and olanzapine treatments in an animal model of mania

Objective: Bipolar disorder (BD) is a challenging psychiatric disorder and a complex disease. The associated reduction in serum vitamin D3 (VitD3) levels in BD patients and the contribution of zinc (Zn) to the treatment, along with the severe side effects of lithium (Li) treatment, were encouraging to assess the efficacy of different correlated combinations of therapeutic/nutraceutical treatments such as olanzapine (Oln), VitD3, and Zn against Li. Methods: Mania was induced in C57BL/6 mice by administering methylphenidate (MPH) for 14 consecutive days. On the 8th day of MPH injection, different treatment regimens were administered, Li, Oln, VitD3/Zn, VitD3/Zn/Oln, VitD3 + Zn + Oln + Li50mg/kg (C50), and VitD3 + Zn + Oln + Li100mg/kg (C100). Both VitD3 (850 IU/kg) and Zn (180 mg/kg) were supplied with food for 2 weeks before starting the induction of mania, which continued until the end of MPH administration. Behavioral, brain oxidative stress, thyroid hormones, VitD3, Zn, GsK-3β, and Bcl2 levels, as well as brain histopathological alterations, were assessed. Results: Manic mice exhibited alterations in all tested parameters, and the histopathological examination of the cortex and hippocampus confirmed these results. The VitD3/Zn/Oln, C50, and C100 treatment regimens reversed most of the behavioral and pathophysiological alterations; however, the C50 treatment regimen was the most efficient. Conclusions: This study emphasizes the importance of combining different antimanic medications like Li and Oln with nutraceutical supplements to increase their antimanic efficacy, reduce their adverse effects, and, ideally, improve the BD patient's quality of life.

Unraveling the role of the renin-angiotensin system in severe mental illnesses: An insight into psychopathology and cognitive deficits

Severe mental illnesses (SMI), especially schizophrenia and bipolar disorder (BD), are associated with significant distress to patients, reduced life expectancy and a higher cost of care. There is growing evidence that SMI may increase the risk of dementia in later life, posing an additional challenge in the management of these patients. SMI present a complex and highly heterogeneous pathophysiology, which has hampered the understanding of its underlying pathological mechanisms and limited the success of the available therapies. Despite the advances in therapeutic approaches in psychiatry over the past decades, treatment resistance is still a common problem in clinical practice, highlighting the urgent need for novel therapeutic targets for SMI. The discovery that renin-angiotensin system (RAS) components are expressed in the central nervous system opened new possibilities for investigating a potential role for this system in the neurobiology of SMI. The safety and efficacy of AT1 receptor blockers and angiotensin-converting enzyme inhibitors in cardiovascular and metabolic diseases, common medical comorbidities among SMI patients and well-known risk factors for dementia, suggest the potential scalability of these strategies for the management of SMI outcomes including the risk of subsequent dementia. This review aimed to discuss the available evidence from animal models and human studies of the potential involvement of RAS in the pathophysiology of SMI. We also provided a reflection on drawbacks and perspectives that can foster the development of new related therapeutic strategies.

Deletion of histamine H2 receptor in VTA dopaminergic neurons of mice induces behavior reminiscent of mania

Hyperfunction of the dopamine system has been implicated in manic episodes in bipolar disorders. How dopaminergic neuronal function is regulated in the pathogenesis of mania remains unclear. Histaminergic neurons project dense efferents into the midbrain dopaminergic nuclei. Here, we present mice lacking dopaminergic histamine H2 receptor (H2R) in the ventral tegmental area (VTA) that exhibit a behavioral phenotype mirroring some of the symptoms of mania, including increased locomotor activity and reduced anxiety- and depression-like behavior. These behavioral deficits can be reversed by the mood stabilizers lithium and valproate. H2R deletion in dopaminergic neurons significantly enhances neuronal activity, concurrent with a decrease in the γ-aminobutyric acid (GABA) type A receptor (GABAAR) membrane presence and inhibitory transmission. Conversely, either overexpression of H2R in VTA dopaminergic neurons or treatment of H2R agonist amthamine within the VTA counteracts amphetamine-induced hyperactivity. Together, our results demonstrate the engagement of H2R in reducing VTA dopaminergic activity, shedding light on the role of H2R as a potential target for mania therapy.

The emerging neuroimmune hypothesis of bipolar disorder: An updated overview of neuroimmune and microglial findings

Bipolar disorder (BD) is a severe and multifactorial disease, with onset usually in young adulthood, which follows a progressive course throughout life. Replicated epidemiological studies have suggested inflammatory mechanisms and neuroimmune risk factors as primary contributors to the onset and development of BD. While not all patients display overt markers of inflammation, significant evidence suggests that aberrant immune signaling contributes to all stages of the disease and seems to be mood phase dependent, likely explaining the heterogeneity of findings observed in this population. As the brain's immune cells, microglia orchestrate the brain's immune response and play a critical role in maintaining the brain's health across the lifespan. Microglia are also highly sensitive to environmental changes and respond to physiological and pathological events by adapting their functions, structure, and molecular expression. Recently, it has been highlighted that instead of a single population of cells, microglia comprise a heterogeneous community with specialized states adjusted according to the local molecular cues and intercellular interactions. Early evidence has highlighted the contribution of microglia to BD neuropathology, notably for severe outcomes, such as suicidality. However, the roles and diversity of microglial states in this disease are still largely undermined. This review brings an updated overview of current literature on the contribution of neuroimmune risk factors for the onset and progression of BD, the most prominent neuroimmune abnormalities (including biomarker, neuroimaging, ex vivo studies) and the most recent findings of microglial involvement in BD neuropathology. Combining these different shreds of evidence, we aim to propose a unifying hypothesis for BD pathophysiology centered on neuroimmune abnormalities and microglia. Also, we highlight the urgent need to apply novel multi-system biology approaches to characterize the diversity of microglial states and functions involved in this enigmatic disorder, which can open bright perspectives for novel biomarkers and therapeutic discoveries.

Intracellular effects of lithium in aging neurons

Lithium therapy received approval during the 1970s, and it has been used for its antidepressant, antimanic, and anti-suicidal effects for acute and long-term prophylaxis and treatment of bipolar disorder (BPD). These properties have been well established; however, the molecular and cellular mechanisms remain controversial. In the past few years, many studies demonstrated that at the cellular level, lithium acts as a regulator of neurogenesis, aging, and Ca2+ homeostasis. At the molecular level, lithium modulates aging by inhibiting glycogen synthase kinase-3β (GSK-3β), and the phosphatidylinositol (PI) cycle; latter, lithium specifically inhibits inositol production, acting as a non-competitive inhibitor of inositol monophosphatase (IMPase). Mitochondria and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) have been related to lithium activity, and its regulation is mediated by GSK-3β degradation and inhibition. Lithium also impacts Ca2+ homeostasis in the mitochondria modulating the function of the lithium-permeable mitochondrial Na+-Ca2+exchanger (NCLX), affecting Ca2+ efflux from the mitochondrial matrix to the endoplasmic reticulum (ER). A close relationship between the protease Omi, GSK-3β, and PGC-1α has also been established. The purpose of this review is to summarize some of the intracellular mechanisms related to lithium activity and how, through them, neuronal aging could be controlled.

Doxycycline reversal of amphetamine-induced mania-like behavior is related to adjusting brain monoamine abnormalities and antioxidant effects in primary hippocampal neurons

Mania is associated with disturbed dopaminergic transmission in frontotemporal regions. D-amphetamine (AMPH) causes increased extracellular DA levels, considered an acknowledged mania model in rodents. Doxycycline (DOXY) is a second-generation tetracycline with promising neuroprotective properties. Here, we tested the hypothesis that DOXY alone or combined with Lithium (Li) could reverse AMPH-induced mania-like behavioral alterations in mice by the modulation of monoamine levels in brain areas related to mood regulation, as well as cytoprotective and antioxidant effects in hippocampal neurons. Male Swiss mice received AMPH or saline intraperitoneal (IP) injections for 14 days. Between days 8-14, mice receive further IP doses of DOXY, Li, or their combination. For in vitro studies, we exposed hippocampal neurons to DOXY in the presence or absence of AMPH. DOXY alone or combined with Li reversed AMPH-induced risk-taking behavior and hyperlocomotion. DOXY also reversed AMPH-induced hippocampal and striatal hyperdopaminergia. In AMPH-exposed hippocampal neurons, DOXY alone and combined with Li presented cytoprotective and antioxidant effects, while DOXY+Li also increased the expression of phospho-Ser133-CREB. Our results add novel evidence for DOXY's ability to reverse mania-like features while revealing that antidopaminergic activity in some brain areas, such as the hippocampus and striatum, as well as hippocampal cytoprotective effects may account for this drug's antimanic action. This study provides additional rationale for designing clinical trials investigating its potential as a mood stabilizer agent.

Anti-manic effect of deep brain stimulation of the ventral tegmental area in an animal model of mania induced by methamphetamine

BACKGROUND

Treatment of refractory bipolar disorder (BD) is extremely challenging. Deep brain stimulation (DBS) holds promise as an effective treatment intervention. However, we still understand very little about the mechanisms of DBS and its application on BD.

AIM

The present study aimed to investigate the behavioural and neurochemical effects of ventral tegmental area (VTA) DBS in an animal model of mania induced by methamphetamine (m-amph).

METHODS

Wistar rats were given 14 days of m-amph injections, and on the last day, animals were submitted to 20 min of VTA DBS in two different patterns: intermittent low-frequency stimulation (LFS) or continuous high-frequency stimulation (HFS). Immediately after DBS, manic-like behaviour and nucleus accumbens (NAc) phasic dopamine (DA) release were evaluated in different groups of animals through open-field tests and fast-scan cyclic voltammetry. Levels of NAc dopaminergic markers were evaluated by immunohistochemistry.

RESULTS

M-amph induced hyperlocomotion in the animals and both DBS parameters reversed this alteration. M-amph increased DA reuptake time post-sham compared to baseline levels, and both LFS and HFS were able to block this alteration. LFS was also able to reduce phasic DA release when compared to baseline. LFS was able to increase dopamine transporter (DAT) expression in the NAc.

CONCLUSION

These results demonstrate that both VTA LFS and HFS DBS exert anti-manic effects and modulation of DA dynamics in the NAc. More specifically the increase in DA reuptake driven by increased DAT expression may serve as a potential mechanism by which VTA DBS exerts its anti-manic effects.

Associations between dietary habits and bipolar disorder: a diet-wide mendelian randomization study

Background

Diet/nutrition is critically important in the pathogenesis, progression, and treatment outcomes of various mental disorders. Current research predominantly focuses on the role of diet in the development and treatment of depression, with less attention given to the relationship between diet and Bipolar Disorder (BD).

Method

We employed Mendelian Randomization (MR) to investigate the relationship between 28 dietary habits and BD. An analysis was conducted using publicly available genome-wide association study data from the UK Biobank dataset. Various dietary habits were analyzed as exposures with BD as the outcome, mainly using the Inverse Variance Weighted (IVW) method.

Results

Intake of non-oily fish and sponge pudding both have a positive association with BD. Oily fish, dried fruit, apples, salt, and cooked vegetables intake also appeared potentially risky for BD, although the possibility of false positives cannot be ruled out. Sensitivity analysis further confirmed the robustness of these findings.

Conclusion

Our research provides evidence of a relationship between various dietary habits and BD. It underscores the need for careful dietary management and balance to reduce the risk of BD, suggesting caution with dietary preferences for fish and sponge pudding. Furthermore, more detailed studies are needed to further understand the potential impacts of high-sugar and high-protein diets on BD development.

Efficacy and safety of established and off-label ADHD drug therapies for cognitive impairment or attention-deficit hyperactivity disorder symptoms in bipolar disorder: A systematic review by the ISBD Targeting Cognition Task Force

BACKGROUND

Abnormalities in dopamine and norepinephrine signaling are implicated in cognitive impairments in bipolar disorder (BD) and attention-deficit hyperactivity disorder (ADHD). This systematic review by the ISBD Targeting Cognition Task Force therefore aimed to investigate the possible benefits on cognition and/or ADHD symptoms and safety of established and off-label ADHD therapies in BD.

METHODS

We included studies of ADHD medications in BD patients, which involved cognitive and/or safety measures. We followed the procedures of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 statement. Searches were conducted on PubMed, Embase and PsycINFO from inception until June 2023. Two authors reviewed the studies independently using the Revised Cochrane Collaboration's Risk of Bias tool for Randomized trials.

RESULTS

Seventeen studies were identified (N = 2136), investigating armodafinil (k = 4, N = 1581), methylphenidate (k = 4, N = 84), bupropion (k = 4, n = 249), clonidine (k = 1, n = 70), lisdexamphetamine (k = 1, n = 25), mixed amphetamine salts (k = 1, n = 30), or modafinil (k = 2, n = 97). Three studies investigated cognition, four ADHD symptoms, and 10 the safety. Three studies found treatment-related ADHD symptom reduction: two involved methylphenidate and one amphetamine salts. One study found a trend towards pro-cognitive effects of modafinil on some cognitive domains. No increased risk of (hypo)mania was observed. Five studies had low risk of bias, eleven a moderate risk, and one a serious risk of bias.

CONCLUSIONS

Methylphenidate or mixed amphetamine salts may improve ADHD symptoms in BD. However, there is limited evidence regarding the effectiveness on cognition. The medications produced no increased mania risk when used alongside mood stabilizers. Further robust studies are needed to assess cognition in BD patients receiving psychostimulant treatment alongside mood stabilizers.

The Pathophysiological Underpinnings of Gamma-Band Alterations in Psychiatric Disorders

Investigating the biophysiological substrates of psychiatric illnesses is of great interest to our understanding of disorders' etiology, the identification of reliable biomarkers, and potential new therapeutic avenues. Schizophrenia represents a consolidated model of γ alterations arising from the aberrant activity of parvalbumin-positive GABAergic interneurons, whose dysfunction is associated with perineuronal net impairment and neuroinflammation. This model of pathogenesis is supported by molecular, cellular, and functional evidence. Proof for alterations of γ oscillations and their underlying mechanisms has also been reported in bipolar disorder and represents an emerging topic for major depressive disorder. Although evidence from animal models needs to be further elucidated in humans, the pathophysiology of γ-band alteration represents a common denominator for different neuropsychiatric disorders. The purpose of this narrative review is to outline a framework of converging results in psychiatric conditions characterized by γ abnormality, from neurochemical dysfunction to alterations in brain rhythms.

L-Carnitine in the Treatment of Psychiatric and Neurological Manifestations: A Systematic Review

OBJECTIVE

L-carnitine (LC), a vital nutritional supplement, plays a crucial role in myocardial health and exhibits significant cardioprotective effects. LC, being the principal constituent of clinical-grade supplements, finds extensive application in the recovery and treatment of diverse cardiovascular and cerebrovascular disorders. However, controversies persist regarding the utilization of LC in nervous system diseases, with varying effects observed across numerous mental and neurological disorders. This article primarily aims to gather and analyze database information to comprehensively summarize the therapeutic potential of LC in patients suffering from nervous system diseases while providing valuable references for further research.

METHODS

A comprehensive search was conducted in PubMed, Web Of Science, Embase, Ovid Medline, Cochrane Library and Clinicaltrials.gov databases. The literature pertaining to the impact of LC supplementation on neurological or psychiatric disorders in patients was reviewed up until November 2023. No language or temporal restrictions were imposed on the search.

RESULTS

A total of 1479 articles were retrieved, and after the removal of duplicates through both automated and manual exclusion processes, 962 articles remained. Subsequently, a meticulous re-screening led to the identification of 60 relevant articles. Among these, there were 12 publications focusing on hepatic encephalopathy (HE), while neurodegenerative diseases (NDs) and peripheral nervous system diseases (PNSDs) were represented by 9 and 6 articles, respectively. Additionally, stroke was addressed in five publications, whereas Raynaud's syndrome (RS) and cognitive disorder (CD) each had three dedicated studies. Furthermore, migraine, depression, and amyotrophic lateral sclerosis (ALS) each accounted for two publications. Lastly, one article was found for other symptoms under investigation.

CONCLUSION

In summary, LC has demonstrated favorable therapeutic effects in the management of HE, Alzheimer's disease (AD), carpal tunnel syndrome (CTS), CD, migraine, neurofibromatosis (NF), PNSDs, RS, and stroke. However, its efficacy appears to be relatively limited in conditions such as ALS, ataxia, attention deficit hyperactivity disorder (ADHD), depression, chronic fatigue syndrome (CFS), Down syndrome (DS), and sciatica.

Pharmacological Mechanism of Herbal Interventions for Bipolar Disorder

Bipolar disorder is a neuropsychiatric disease characterized by an abundance of undesired ideas and thoughts associated with recurrent episodes of mania or hypomania and depression. Alterations in the circuits, including the prefrontal cortex, striatum, and limbic system, regulate mood and cause variation in several crucial neurotransmitters, including serotonin, dopamine, GABA, and glutamate. Imbalances in dopamine levels have been implicated in the manic phase, while variance in serotonin is linked to depressive episodes. The precise pathophysiology of bipolar disorder is still unknown. Though different treatments are available, like lithium, risperidone, valproic acid, etc., which are widely used, they come with certain limitations, including narrow therapeutic index, hypothyroidism, weight gain, extrapyramidal symptoms, etc. The interest in herbal- based treatments for bipolar disorder arises from the desire for alternative, potentially more natural, and holistic approaches with fewer side effects. The current review focuses on the potential effects of herbal drugs and their derivatives to alleviate the symptoms of bipolar disorder.

Examining the link between impulse control disorder and antidepressant use in Parkinson's disease

INTRODUCTION

Impulse control disorders (ICD) in Parkinson's disease (PD) and hypomanic episodes of bipolar disorder show overlapping symptoms, suggesting a shared neurobiology. To explore this, the following hypotheses are tested: (1) larger changes in affective symptoms from OFF to ON medication states will be associated with ICD, (2) antidepressant exposure will be associated with larger OFF to ON affective symptom changes, and (3) antidepressant exposure will be associated with ICD.

METHODS

200 participants (mean age 65, 61 % male) were evaluated in "off" and "on" dopamine states. Affective symptoms were captured using the Hamilton Anxiety and Depression Rating Scales. Differences in clinical outcomes were compared using two-sample Wilcoxon rank-sum tests and Pearson χ2 tests. We performed multivariable logistic regression to assess the association of antidepressant exposure on ICD.

RESULTS

Participants with an ICD had higher anxiety and depressive scores in "on" and "off" states and larger changes in depressive symptoms from OFF to ON states compared to those without an ICD. Participants on antidepressants had higher anxiety scores in "on" and "off" states, higher depressive scores in the "off" state, and larger changes in anxiety symptoms from OFF to ON states than those not on an antidepressant. Antidepressant use was associated with a higher odds of an ICD (OR 2.3, CI [1.0-4.5], p-value 0.04).

CONCLUSIONS

Affective symptom severity in "on" and "off" dopamine states is associated with ICD. Antidepressant therapy may be associated with ICD. Future prospective studies clarifying temporal associations between antidepressant initiation and ICD emergence are needed.

Case report: Dopamine Dysregulation Syndrome, mania, and compulsive buying in a patient with Parkinson's disease

Neuropsychiatric symptoms and syndromes are among the most common non-motor symptoms of Parkinson's Disease but they are frequently unrecognized and untreated. Dopamine Dysregulation Syndrome is an uncommon complication of the treatment of Parkinson's disease, characterized by an addictive use of dopamine far more than the dosage required for treatment of objective motor impairment, leading to severe dyskinesia, euphoria, aggressivity, or psychosis. We present a paradigmatic case of Dopamine Dysregulation Syndrome, Mania, and Compulsive Buying in a 55-year-old male with Parkinson's Disease. We also reviewed the risk factors and the therapeutic management of Dopamine Dysregulation Syndrome in Parkinson's Disease.

Oxycodone-induced dopaminergic and respiratory effects are modulated by deep brain stimulation

Introduction: Opioids are the leading cause of overdose death in the United States, accounting for almost 70,000 deaths in 2020. Deep brain stimulation (DBS) is a promising new treatment for substance use disorders. Here, we hypothesized that VTA DBS would modulate both the dopaminergic and respiratory effect of oxycodone. Methods: Multiple-cyclic square wave voltammetry (M-CSWV) was used to investigate how deep brain stimulation (130 Hz, 0.2 ms, and 0.2 mA) of the rodent ventral segmental area (VTA), which contains abundant dopaminergic neurons, modulates the acute effects of oxycodone administration (2.5 mg/kg, i.v.) on nucleus accumbens core (NAcc) tonic extracellular dopamine levels and respiratory rate in urethane-anesthetized rats (1.5 g/kg, i.p.). Results: I.V. administration of oxycodone resulted in an increase in NAcc tonic dopamine levels (296.9 ± 37.0 nM) compared to baseline (150.7 ± 15.5 nM) and saline administration (152.0 ± 16.1 nM) (296.9 ± 37.0 vs. 150.7 ± 15.5 vs. 152.0 ± 16.1, respectively, p = 0.022, n = 5). This robust oxycodone-induced increase in NAcc dopamine concentration was associated with a sharp reduction in respiratory rate (111.7 ± 2.6 min-1 vs. 67.9 ± 8.3 min-1; pre- vs. post-oxycodone; p < 0.001). Continuous DBS targeted at the VTA (n = 5) reduced baseline dopamine levels, attenuated the oxycodone-induced increase in dopamine levels to (+39.0% vs. +95%), and respiratory depression (121.5 ± 6.7 min-1 vs. 105.2 ± 4.1 min-1; pre- vs. post-oxycodone; p = 0.072). Discussion: Here we demonstrated VTA DBS alleviates oxycodone-induced increases in NAcc dopamine levels and reverses respiratory suppression. These results support the possibility of using neuromodulation technology for treatment of drug addiction.

Amantadine in Treatment of Dysthymia-The Pilot Case Series Study

Dysthymia is a common chronic mood disorder in which isolated symptoms of depression persist for at least 2 years. Despite the many medications recommended for the treatment of dysthymia, no recommendations have yet been made for the treatment of patients who fail to achieve clinical improvement. This justifies attempts to identify second-line drugs for the treatment of dysthymia. In an open and naturalistic case study, five patients diagnosed with dysthymia in whom at least one antidepressant treatment was ineffective were treated with amantadine. In the age- and gender-matched external control group, patients were treated with sertraline at 100 mg/day. Depressive symptoms were assessed using HDRS-17. Two men and three women were treated with 100 mg amantadine for 3 months with 3-5 months follow-up. After 1 month of treatment with amantadine, a significant reduction in the intensity of depressive symptoms was achieved in all patients, and the clinical improvement increased over the next 2 months of treatment. No deterioration in well-being was observed in any patient after discontinuation of amantadine. The effect of amantadine treatment was comparable to that of sertraline treatment in patients with dysthymia who improved with this drug. The present study indicates that amantadine is an effective and well-tolerated drug in the treatment of dysthymia. Amantadine may be associated with a quick improvement in symptoms in the treatment of dysthymia. Treatment with this drug seems to be associated with good tolerability and persistency of the therapeutic effect after the discontinuation of the treatment.

Effects of varenicline on the serum levels of olanzapine in male patients with Schizophrenia: a randomized controlled trial

Background

Smoking in patients with Schizophrenia is more common than in the general population. Varenicline, a partial agonist at α4β2 nicotinic acetylcholine receptors, is an effective smoking cessation pharmacotherapy in patients with Schizophrenia. However, its effects on the serum levels of antipsychotics in Schizophrenia are understudied. This study investigated the impact of smoking cessation with varenicline on the serum concentration of olanzapine in patients with Schizophrenia.

Methods

Adult smokers with Schizophrenia were enrolled in a 12-week course of varenicline and placebo for smoking cessation. The serum concentration of olanzapine was measured at baseline and weeks 1, 2, 4, 8, and 12. Data were analyzed with the generalized additive mixed model.

Results

During the 12-week study, the results indicated that olanzapine concentrations increased nonlinearly in the varenicline and placebo groups. Threshold effect analysis suggested that the olanzapine concentrations increased over time until the turning point (week 4). However, there was no significant difference between the two treatment groups.

Conclusion

Varenicline showed safety and efficacy in smoking cessation in people with Schizophrenia.

Absconding among admitted patients with bipolar affective disorder diagnosis in Uganda

BACKGROUND

Hospitalization is often necessary for individuals with Bipolar affective Disorder (BAD) during severe manic or depressive episodes, as well as for stabilizing treatment regimens. However, a significant proportion of patients admitted for treatment of BAD abscond or leave the hospital without permission during their stay. In addition, patients managed for BAD may have unique characteristics that might force them into absconding. For example, the high prevalence of co-morbid substance use disorder - craving to use substances, suicidal behaviors - attempts to die by suicide, and cluster B personality disorders - characterized by impulsive acts. It is, therefore, essential to understand the factors contributing to absconding among patients with BAD, to facilitate designing strategies for preventing and managing this behavior.

METHOD

This study was based on a retrospective chart review of the inpatients diagnosed with BAD at a tertiary psychiatry facility in Uganda from January 2018 to December 2021.

RESULTS

Approximately 7.8% of those with BAD absconded from the hospital. The likelihood of absconding among those with BAD increased with the use of cannabis [adjusted odds ratio (aOR) = 4.00, 95% confidence interval (CI) = 1.22-13.09, p-value = 0.022] and having mood lability [aOR = 2.15, 95% CI = 1.10-4.21, p-value = 0.025]. However, receiving psychotherapy during the admission (aOR = 0.44, 95 CI = 0.26-0.74, p-value = 0.002) and treatment with haloperidol (aOR = 0.39, 95% CI = 0.18-0.83, p-value = 0.014) reduced the likelihood of absconding.

CONCLUSION

Absconding among patients with BAD is common in Uganda. Those with symptoms of affective lability and those with comorbid cannabis use tend to abscond more, while those who receive haloperidol and psychotherapy are less likely to abscond.

Gait disorders in unipolar and bipolar depression

Objectives

Bipolar and unipolar depressions have a similar clinical picture, but different neurological and psychological mechanisms. These misleading similarities can lead to overdiagnosis and increased suicide risk. Recent studies show that gait is a sensitive objective marker for distinguishing the type of depression. The present study aims to compare psychomotor reactivity disorders and gait activity in unipolar and bipolar depression.

Methods

A total of 636 people aged 40.7 ± 11.2 years are studied with an ultrasound cranio-corpo-graph. They are divided into three groups - patients with unipolar depression, with bipolar depression and healthy controls. Each person performs three psychomotor tasks - a classic Unterberger task, a simplified version with open eyes and a complex version with an additional cognitive task.

Results

We find significant differences in psychomotor activity and reactivity between the three groups. Bipolar patients have more inhibited psychomotor skills than unipolar and they are both more inhibited than the norms. The simplified variant of the equilibriometric task is the most sensitive one and psychomotor reactivity is a more precise marker than psychomotor activity.

Conclusion

Both psychomotor activity and reactivity in gait could be sensitive markers for distinguishing similar psychiatric conditions. The application of the cranio-corpo-graph and the possible development of similar devices could lead to new diagnostic and therapeutic approaches, including early detection and prediction of the type of depression.

Mood and behavior regulation: interaction of lithium and dopaminergic system

Lithium is one of the most effect mood-stabilizing drugs prescribed especially for bipolar disorder. Lithium has wide range effects on different molecular factors and neural transmission including dopaminergic signaling. On the other hand, mesolimbic and mesocortical dopaminergic signaling is significantly involved in the pathophysiology of neuropsychiatric disorders. This review article aims to study lithium therapeutic mechanisms, dopaminergic signaling, and the interaction of lithium and dopamine. We concluded that acute and chronic lithium treatments often reduce dopamine synthesis and level in the brain. However, some studies have reported conflicting results following lithium treatment, especially chronic treatment. The dosage, duration, and type of lithium administration, and the brain region selected for measuring dopamine level were not significant differences in different chronic treatments used in previous studies. It was suggested that lithium has various mechanisms affecting dopaminergic signaling and mood, and that many molecular factors can be involved, including brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), β-catenin, protein kinase B (Akt), and glycogen synthase kinase-3 beta (GSK-3β). Thus, molecular effects of lithium can be the most important mechanisms of lithium that also alter neural transmissions including dopaminergic signaling in mesolimbic and mesocortical pathways.

Comparative efficacy, acceptability, and tolerability of adjunctive anti-inflammatory agents on bipolar disorder: A systemic review and network meta-analysis

OBJECTIVES

We performed a network meta-analysis (NMA) with up-to-date evidence to compare different anti-inflammatory agents to improve the treatment of bipolar disorder (BD) patients.

METHODS

Four databases (i.e., the Cochrane Library, Web of Science, PubMed, and Embase) were searched for randomized controlled trials (RCTs) published between 1995 and 2022 on the use of anti-inflammatory agents in the treatment of BD. A systematic review and NMA were conducted.

RESULTS

Adjunctive N-acetylcysteine (NAC) was superior to placebo for the treatment of BD according to the endpoint scale score (SMD -0.65, 95% confidence interval (CI): - 0.99 to - 0.31), response rate (odds ratio (OR) 3.42, 95% CI: 1.23-9.52), remission rate (OR 4.94, 95% CI: 1.03-41.38) and surface under the cumulative ranking curve (SUCRA) value of the endpoint scale score (0.84). Adjunctive nonsteroidal anti-inflammatory drugs (NSAIDs) were more favorable than placebo based on the remission rate (OR 3.93, 95% CI: 1.15-13.43) and were significantly more acceptable than other treatments (OR 0.60, 95% CI: 0.36-0.99). Adjunctive coenzyme Q10 (CoQ10) was superior to other agents in terms of the response rate (OR 18.85, 95% CI: 2.63-135.00), with a SUCRA value for the response rate of 0.90 and that for the remission rate of 0.71.

CONCLUSION

Adjunctive NAC is recommended for the treatment of BD. Adjunctive NSAIDs and CoQ10 are still seen as effective, but more high-quality clinical studies are needed to verify their efficacy. Other anti-inflammatory agents may not be recommended for clinical use at present. All anti-inflammatory agents demonstrated a good safety profile. We call for further research on the combined treatment of BD with different anti-inflammatory agents to be included in future trials.

High frequency deep brain stimulation can mitigate the acute effects of cocaine administration on tonic dopamine levels in the rat nucleus accumbens

Cocaine's addictive properties stem from its capacity to increase tonic extracellular dopamine levels in the nucleus accumbens (NAc). The ventral tegmental area (VTA) is a principal source of NAc dopamine. To investigate how high frequency stimulation (HFS) of the rodent VTA or nucleus accumbens core (NAcc) modulates the acute effects of cocaine administration on NAcc tonic dopamine levels multiple-cyclic square wave voltammetry (M-CSWV) was used. VTA HFS alone decreased NAcc tonic dopamine levels by 42%. NAcc HFS alone resulted in an initial decrease in tonic dopamine levels followed by a return to baseline. VTA or NAcc HFS following cocaine administration prevented the cocaine-induced increase in NAcc tonic dopamine. The present results suggest a possible underlying mechanism of NAc deep brain stimulation (DBS) in the treatment of substance use disorders (SUDs) and the possibility of treating SUD by abolishing dopamine release elicited by cocaine and other drugs of abuse by DBS in VTA, although further studies with chronic addiction models are required to confirm that. Furthermore, we demonstrated the use of M-CSWV can reliably measure tonic dopamine levels in vivo with both drug administration and DBS with minimal artifacts.

Circadian rhythms as modulators of brain health during development and throughout aging

The circadian clock plays a prominent role in neurons during development and throughout aging. This review covers topics pertinent to the role of 24-h rhythms in neuronal development and function, and their tendency to decline with aging. Pharmacological or behavioral modification that augment the function of our internal clock may be central to decline of cognitive disease and to future chronotherapy for aging-related diseases of the central nervous system.

Inhibition of glycogen synthase kinase 3 by lithium, a mechanism in search of specificity

Inhibition of Glycogen synthase kinase 3 (GSK3) is a popular explanation for the effects of lithium ions on mood regulation in bipolar disorder and other mental illnesses, including major depression, cyclothymia, and schizophrenia. Contribution of GSK3 is supported by evidence obtained from animal and patient derived model systems. However, the two GSK3 enzymes, GSK3α and GSK3β, have more than 100 validated substrates. They are thus central hubs for major biological functions, such as dopamine-glutamate neurotransmission, synaptic plasticity (Hebbian and homeostatic), inflammation, circadian regulation, protein synthesis, metabolism, inflammation, and mitochondrial functions. The intricate contributions of GSK3 to several biological processes make it difficult to identify specific mechanisms of mood stabilization for therapeutic development. Identification of GSK3 substrates involved in lithium therapeutic action is thus critical. We provide an overview of GSK3 biological functions and substrates for which there is evidence for a contribution to lithium effects. A particular focus is given to four of these: the transcription factor cAMP response element-binding protein (CREB), the RNA-binding protein FXR1, kinesin subunits, and the cytoskeletal regulator CRMP2. An overview of how co-regulation of these substrates may result in shared outcomes is also presented. Better understanding of how inhibition of GSK3 contributes to the therapeutic effects of lithium should allow for identification of more specific targets for future drug development. It may also provide a framework for the understanding of how lithium effects overlap with those of other drugs such as ketamine and antipsychotics, which also inhibit brain GSK3.

Is SARS-CoV-2 a Risk Factor of Bipolar Disorder?-A Narrative Review

For 2.5 years we have been facing the coronavirus disease (COVID-19) and its health, social and economic effects. One of its known consequences is the development of neuropsychiatric diseases such as anxiety and depression. However, reports of manic episodes related to COVID-19 have emerged. Mania is an integral part of the debilitating illness-bipolar disorder (BD). Due to its devastating effects, it is therefore important to establish whether SARS-CoV-2 infection is a causative agent of this severe mental disorder. In this narrative review, we discuss the similarities between the disorders caused by SARS-CoV-2 and those found in patients with BD, and we also try to answer the question of whether SARS-CoV-2 infection may be a risk factor for the development of this affective disorder. Our observation shows that disorders in COVID-19 showing the greatest similarity to those in BD are cytokine disorders, tryptophan metabolism, sleep disorders and structural changes in the central nervous system (CNS). These changes, especially intensified in severe infections, may be a trigger for the development of BD in particularly vulnerable people, e.g., with family history, or cause an acute episode in patients with a pre-existing BD.

Schizophrenia, Bipolar and Major Depressive Disorders: Overview of Clinical Features, Neurotransmitter Alterations, Pharmacological Interventions, and Impact of Oxidative Stress in the Disease Process

Psychiatric disorders are one of the leading causes of disability worldwide and affect the quality of life of both individuals and the society. The current understanding of these disorders points toward receptor dysfunction and neurotransmitter imbalances in the brain. Treatment protocols are hence oriented toward normalizing these imbalances and ameliorating the symptoms. However, recent literature has indicated the possible role of depleted levels of antioxidants like glutathione (GSH) as well as an alteration in the levels of the pro-oxidant, iron in the pathogenesis of major psychiatric diseases, viz., schizophrenia (Sz), bipolar disorder (BD), and major depressive disorder (MDD). This review aims to highlight the involvement of oxidative stress (OS) in these psychiatric disorders. An overview of the clinical features, neurotransmitter abnormalities, and pharmacological treatments concerning these psychiatric disorders has also been presented. Furthermore, it attempts to synthesize literature from existing magnetic resonance spectroscopy (MRS) and quantitative susceptibility mapping (QSM) studies for these disorders, assessing GSH and iron, respectively. This manuscript is a sincere attempt to stimulate research discussion to advance the knowledge base for further understanding of the pathoetiology of Sz, BD, and MDD.

A motivation model of sex addiction - Relevance to the controversy over the concept

An integrative model of sexual addiction is presented, involving a combination of models based upon (i) incentive motivation theory and (ii) the dual organisation of the control of behavior. The model is related to ongoing arguments about the validity of the notion of addiction when applied to sexual behavior. It is suggested that the evidence strongly favors the viability of an addiction model of sex. Strong similarities to the classical addiction to hard drugs are observed and features can be better understood with the help of the model. These include tolerance, escalation and withdrawal symptoms. It is argued that other candidates for accounting for the phenomena, such as obsessive-compulsive behavior, faulty impulse control, high drive and hypersexuality do not fit the evidence. The role of dopamine is central to the model. The model's relevance to stress, abuse, development, psychopathy, fantasy, sex differences, evolutionary psychology and the interaction with drug-taking is shown.

Association of Polymorphism within the Putative miRNA Target Site in the 3'UTR Region of the DRD2 Gene with Neuroticism in Patients with Substance Use Disorder

The study aims at looking into associations between the polymorphism rs6276 that occurs in the putative miRNA target site in the 3'UTR region of the DRD2 gene in patients with substance use disorder (SUD) comorbid with a maniacal syndrome (SUD MANIA). In our study, we did not state any essential difference in DRD2 rs6276 genotype frequencies in the studied samples of SUD MANIA, SUD, and control subjects. A significant result was found for the SUD MANIA group vs. SUD vs. controls on the Neuroticism Scale of NEO FFI test, and DRD2 rs6276 (p = 0.0320) accounted for 1.7% of the variance. The G/G homozygous variants were linked with lower results on the neuroticism scale in the SUD MANIA group because G/G alleles may serve a protective role in the expression of neuroticism in patients with SUD MANIA. So far, there have been no data in the literature on the relationship between the miRSNP rs6276 region in the DRD2 gene and neuroticism (personal traits) in patients with a diagnosis of substance use disorder comorbid with the affective, maniacal type disturbances related to SUD. This is the first report on this topic.

Strategies and foundations for scientific discovery in longitudinal studies of bipolar disorder

Bipolar disorder (BD) is a complex and dynamic condition with a typical onset in late adolescence or early adulthood followed by an episodic course with intervening periods of subthreshold symptoms or euthymia. It is complicated by the accumulation of comorbid medical and psychiatric disorders. The etiology of BD remains unknown and no reliable biological markers have yet been identified. This is likely due to lack of comprehensive ontological framework and, most importantly, the fact that most studies have been based on small nonrepresentative clinical samples with cross-sectional designs. We propose to establish large, global longitudinal cohorts of BD studied consistently in a multidimensional and multidisciplinary manner to determine etiology and help improve treatment. Herein we propose collection of a broad range of data that reflect the heterogenic phenotypic manifestations of BD that include dimensional and categorical measures of mood, neurocognitive, personality, behavior, sleep and circadian, life-story, and outcomes domains. In combination with genetic and biological information such an approach promotes the integrating and harmonizing of data within and across current ontology systems while supporting a paradigm shift that will facilitate discovery and become the basis for novel hypotheses.

The effects of early life stress on impulsivity

Elevated impulsivity is a symptom shared by various psychiatric disorders such as substance use disorder, bipolar disorder, and attention-deficit/hyperactivity disorder. However, impulsivity is not a unitary construct and impulsive behaviors fall into two subcategories: impulsive action and impulsive choice. Impulsive choice refers to the tendency to prefer immediate, small rewards over delayed, large rewards, whereas impulsive action involves difficulty inhibiting rash, premature, or mistimed behaviors. These behaviors are mediated by the mesocorticolimbic dopamine (DA) system, which consists of projections from the ventral tegmental area to the nucleus accumbens and prefrontal cortex. Early life stress (ELS) alters both impulsive choice and impulsive action in rodents. ELS also changes DA receptor expression, transmission, and activity within the mesocorticolimbic system. This review integrates the dopamine, impulsivity, and ELS literature to provide evidence that ELS alters impulsivity via inducing changes in the mesocorticolimbic DA system. Understanding how ELS affects brain circuits associated with impulsivity can help advance treatments aimed towards reducing impulsivity symptoms in a variety of psychiatric disorders.

Bipolar Spectrum disorders in Parkinson's disease: a systematic evaluation

OBJECTIVE

Psychiatric disorders are very common in patients affected by Parkinson's disease (PD). However, comorbidity with Bipolar Spectrum disorders is understudied. The aim of this study is to explore the clinical correlates of PD associated with Bipolar Spectrum disorders.

METHODS

One hundred PD patients were screened for psychiatric comorbidities, cognitive profile, motor, and non-motor symptoms. The sample was divided into three groups: PD-patients with Bipolar Spectrum disorders (bipolar disorder type I, type II, and spontaneous or induced hypomania; N = 32), PD-patients with others psychiatric comorbidities (N = 39), PD-patients without psychiatric comorbidities (N = 29). Clinical features were compared among the groups using analysis of variance and chi-square test. A logistic regression was performed to evaluate the association between Bipolar Spectrum disorders and early onset of PD (≤50 years) controlling for lifetime antipsychotic use.

RESULTS

In comparison with PD patients with and without other psychiatric comorbidity, subjects affected by Bipolar Spectrum disorders were younger, showed more frequently an early onset PD, reported more involuntary movements and a higher rate of impulse control disorders and compulsive behaviors. No differences were observed in indexes of exposure to dopamine agonist treatments. The early onset of PD was predicted by Bipolar Spectrum comorbidity, independently from lifetime antipsychotic use.

CONCLUSION

Bipolar Spectrum disorders are common in early onset PD. The presence of bipolar comorbidity could identify a particular subtype of PD, showing higher rates of neurological and psychiatric complications and deserving further investigation.

Neuromolecular Etiology of Bipolar Disorder: Possible Therapeutic Targets of Mood Stabilizers

Bipolar disorder is a mental illness that causes extreme mood swings and has a chronic course. However, the mechanism by which mood episodes with completely opposite characteristics appear repeatedly, or a mixture of symptoms appears, in patients with bipolar disorder remains unknown. Therefore, mood stabilizers are indicated only for single mood episodes, such as manic episodes and depressive episodes, and no true mood-stabilizing drugs effective for treating both manic and depressive episodes currently exist. Therefore, in this review, therapeutic targets that facilitate the development of mood stabilizers were examined by reviewing the current understanding of the neuromolecular etiology of bipolar disorder.

Risperidone Induced Hyperprolactinemia: From Basic to Clinical Studies

Risperidone is one of the most commonly used antipsychotics (AP), due to its safety and efficacy in reducing psychotic symptoms. Despite the favorable side effect profile, the therapy is accompanied by side effects due to the non-selectivity of this medicine. This review will briefly highlight the most important basic and clinical findings in this area, consider the clinical effects of AP-induced hyperprolactinemia (HPL), and suggest different approaches to the treatment.The route of application of this drug primarily affects the daily variation and the total concentration of drug levels in the blood, which consequently affects the appearance of side effects, either worsening or even reducing them. Our attention has been drawn to HPL, a frequent but neglected adverse effect observed in cases treated with Risperidone and its secondary manifestations. An increase in prolactin levels above the reference values result in impairment of other somatic functions (lactation, irregular menses, fertility) as well as a significant reduction in quality of life. It has been frequently shown that the side effects of the Risperidone are the most common cause of non-compliance with therapy, resulting in worsening of psychiatric symptoms and hospitalization. However, the mechanism of Risperidone-induced HPL is complicated and still far from fully understood. Most of the preclinical and clinical studies described in this study show that hyperprolactinemia is one of the most common if not the leading side effect of Risperidone therefore to improve the quality of life of these patients, clinicians must recognize and treat HPL associated with the use of these drugs.

Neurobiological and behavioral mechanisms of circadian rhythm disruption in bipolar disorder: A critical multi-disciplinary literature review and agenda for future research from the ISBD task force on chronobiology

AIM

Symptoms of bipolar disorder (BD) include changes in mood, activity, energy, sleep, and appetite. Since many of these processes are regulated by circadian function, circadian rhythm disturbance has been examined as a biological feature underlying BD. The International Society for Bipolar Disorders Chronobiology Task Force (CTF) was commissioned to review evidence for neurobiological and behavioral mechanisms pertinent to BD.

METHOD

Drawing upon expertise in animal models, biomarkers, physiology, and behavior, CTF analyzed the relevant cross-disciplinary literature to precisely frame the discussion around circadian rhythm disruption in BD, highlight key findings, and for the first time integrate findings across levels of analysis to develop an internally consistent, coherent theoretical framework.

RESULTS

Evidence from multiple sources implicates the circadian system in mood regulation, with corresponding associations with BD diagnoses and mood-related traits reported across genetic, cellular, physiological, and behavioral domains. However, circadian disruption does not appear to be specific to BD and is present across a variety of high-risk, prodromal, and syndromic psychiatric disorders. Substantial variability and ambiguity among the definitions, concepts and assumptions underlying the research have limited replication and the emergence of consensus findings.

CONCLUSIONS

Future research in circadian rhythms and its role in BD is warranted. Well-powered studies that carefully define associations between BD-related and chronobiologically-related constructs, and integrate across levels of analysis will be most illuminating.

Treatment-induced mood switching in affective disorders

Many patients under treatment for mood disorders, in particular patients with bipolar mood disorders, experience episodes of mood switching from one state to another. Various hypotheses have been proposed to explain the mechanism of mood switching, spontaneously or induced by drug treatment. Animal models have also been used to test the role of psychotropic drugs in the switching of mood states. We examine the possible relationship between the pharmacology of psychotropic drugs and their reported incidents of induced mood switching, with reference to the various hypotheses of mechanisms of mood switching.

Gut Microbiota – A Potential Contributor in the Pathogenesis of Bipolar Disorder

Bipolar disorder (BD) is one of the major psychiatric disorders that is characterized by recurrent episodes of depression and mania (or hypomania), leading to seriously adverse outcomes with unclear pathogenesis. There is an underlying relationship between bacterial communities residing in the gut and brain function, which together form the gut-brain axis (GBA). Recent studies have shown that changes in the gut microbiota have been observed in a large number of BD patients, so the axis may play a role in the pathogenesis of BD. This review summarizes briefly the relationship between the GBA and brain function, the composition and changes of gut microbiota in patients with BD, and further explores the potential role of GBA-related pathway in the pathogenesis of BD as well as the limitations in this field at present in order to provide new ideas for the future etiology research and drug development.

Therapeutic Interventions to Mitigate Mitochondrial Dysfunction and Oxidative Stress–Induced Damage in Patients with Bipolar Disorder

Bipolar disorder (BD) is characterized by mood changes, including recurrent manic, hypomanic, and depressive episodes, which may involve mixed symptoms. Despite the progress in neurobiological research, the pathophysiology of BD has not been extensively described to date. Progress in the understanding of the neurobiology driving BD could help facilitate the discovery of therapeutic targets and biomarkers for its early detection. Oxidative stress (OS), which damages biomolecules and causes mitochondrial and dopamine system dysfunctions, is a persistent finding in patients with BD. Inflammation and immune dysfunction might also play a role in BD pathophysiology. Specific nutrient supplements (nutraceuticals) may target neurobiological pathways suggested to be perturbed in BD, such as inflammation, mitochondrial dysfunction, and OS. Consequently, nutraceuticals may be used in the adjunctive treatment of BD. This paper summarizes the possible roles of OS, mitochondrial dysfunction, and immune system dysregulation in the onset of BD. It then discusses OS-mitigating strategies that may serve as therapeutic interventions for BD. It also analyzes the relationship between diet and BD as well as the use of nutritional interventions in the treatment of BD. In addition, it addresses the use of lithium therapy; novel antipsychotic agents, including clozapine, olanzapine, risperidone, cariprazine, and quetiapine; and anti-inflammatory agents to treat BD. Furthermore, it reviews the efficacy of the most used therapies for BD, such as cognitive–behavioral therapy, bright light therapy, imagery-focused cognitive therapy, and electroconvulsive therapy. A better understanding of the roles of OS, mitochondrial dysfunction, and inflammation in the pathogenesis of bipolar disorder, along with a stronger elucidation of the therapeutic functions of antioxidants, antipsychotics, anti-inflammatory agents, lithium therapy, and light therapies, may lead to improved strategies for the treatment and prevention of bipolar disorder.

Bipolar spectrum disorders in neurologic disorders

Psychiatric symptoms frequently predate or complicate neurological disorders, such as neurodegenerative diseases. Symptoms of bipolar spectrum disorders (BSD), like mood, behavioral, and psychotic alterations, are known to occur - individually or as a syndromic cluster - in Parkinson's disease and in the behavioral variant of frontotemporal dementia (FTD). Nonetheless, due to shared pathophysiological mechanisms, or genetic predisposition, several other neurological disorders show significant, yet neglected, clinical and biological overlaps with BSD like neuroinflammation, ion channel dysfunctions, neurotransmission imbalance, or neurodegeneration. BSD pathophysiology is still largely unclear, but large-scale network dysfunctions are known to participate in the onset of mood disorders and psychotic symptoms. Thus, functional alterations can unleash BSD symptoms years before the evidence of an organic disease of the central nervous system. The aim of our narrative review was to illustrate the numerous intersections between BSD and neurological disorders from a clinical-biological point of view and the underlying predisposing factors, to guide future diagnostic and therapeutical research in the field.

Lithium as a Neuroprotective Agent for Bipolar Disorder: An Overview

Lithium (Li+) is a first option treatment for adult acute episodes of Bipolar Disorder (BD) and for the prophylaxis of new depressed or manic episodes. It is also the preferred choice as maintenance treatment. Numerous studies have shown morphological abnormalities in the brains of BD patients, suggesting that this highly heritable disorder may exhibit progressive and deleterious changes in brain structure. Since treatment with Li+ ameliorates these abnormalities, it has been postulated that Li+ is a neuroprotective agent in the same way atypical antipsychotics are neuroprotective in patients diagnosed with schizophrenia spectrum disorders. Li+'s neuroprotective properties are related to its modulation of nerve growth factors, inflammation, mitochondrial function, oxidative stress, and programmed cell death mechanisms such as autophagy and apoptosis. Notwithstanding, it is not known whether Li+-induced neuroprotection is related to the inhibition of its putative molecular targets in a BD episode: the enzymes inositol-monophosphatase, (IMPase), glycogen-synthase-kinase 3β (GSK3), and Protein kinase C (PKC). Furthermore, it is uncertain whether these neuroprotective mechanisms are correlated with Li+'s clinical efficacy in maintaining mood stability. It is expected that in a nearby future, precision medicine approaches will improve diagnosis and expand treatment options. This will certainly contribute to ameliorating the medical and economic burden created by this devastating mood disorder.

Morphological and biochemical repercussions of Toxoplasma gondii infection in a 3D human brain neurospheres model

Background

Toxoplasmosis is caused by the parasite Toxoplasma gondii that can infect the central nervous system (CNS), promoting neuroinflammation, neuronal loss, neurotransmitter imbalance and behavioral alterations. T. gondii infection is also related to neuropsychiatric disorders such as schizophrenia. The pathogenicity and inflammatory response in rodents are different to the case of humans, compromising the correlation between the behavioral alterations and physiological modifications observed in the disease. In the present work we used BrainSpheres, a 3D CNS model derived from human pluripotent stem cells (iPSC), to investigate the morphological and biochemical repercussions of T. gondii infection in human neural cells.

Methods

We evaluated T. gondii ME49 strain proliferation and cyst formation in both 2D cultured human neural cells and BrainSpheres. Aspects of cell morphology, ultrastructure, viability, gene expression of neural phenotype markers, as well as secretion of inflammatory mediators were evaluated for 2 and 4 weeks post infection in BrainSpheres.

Results

T. gondii can infect BrainSpheres, proliferating and inducing cysts formation, neural cell death, alteration in neural gene expression and triggering the release of several inflammatory mediators.

Conclusions

BrainSpheres reproduce many aspects of T. gondii infection in human CNS, constituting a useful model to study the neurotoxicity and neuroinflammation mediated by the parasite. In addition, these data could be important for future studies aiming at better understanding possible correlations between psychiatric disorders and human CNS infection with T. gondii.

•

T. gondii infects, proliferates and induce cysts formation in neurospheres.

•

T. gondii infection induces neural cell death in neurospheres.

•

T. gondii infection promotes alteration in neural gene expression in neurospheres.

•

T. gondii infection promotes release of inflammatory mediators in neurospheres.

Sex Differences in Dopamine Receptors and Relevance to Neuropsychiatric Disorders

Dopamine is an important neurotransmitter that plays a key role in neuropsychiatric illness. Sex differences in dopaminergic signaling have been acknowledged for decades and have been linked to sex-specific heterogeneity in both dopamine-related behaviours as well as in various neuropsychiatric disorders. However, the overall number of studies that have evaluated sex differences in dopamine signaling, both in health and in these disorders, is low. This review will bring together what is known regarding sex differences in innate dopamine receptor expression and function, as well as highlight the known sex-specific roles of dopamine in addiction, depression, anxiety, schizophrenia, and attention deficit hyperactivity disorder. Due to differences in prognosis, diagnosis, and symptomatology between male and female subjects in disorders that involve dopamine signaling, or in responses that utilize pharmacological interventions that target dopamine receptors, understanding the fundamental sex differences in dopamine receptors is of vital importance for the personalization of therapeutic treatment strategies.

Incidence of Parkinson's disease, dementia, cerebrovascular disease and stroke in bipolar disorder compared to other psychiatric disorders: An electronic health records network study of 66 million people

OBJECTIVES

Bipolar disorder has been associated with an increased risk for neurodegenerative diseases, but uncertainties remain. The risk relative to other psychiatric disorders is not established.

METHODS

We used a federated electronic health records network of 66 million people including over 700,000 with bipolar disorder. We assessed incidence of a first diagnosis of Parkinson's disease, dementia, cerebrovascular disease and stroke, in patients at least 1 year after diagnosis of bipolar disorder. Rates were compared to propensity score matched cohorts of subjects with mixed disorders, recurrent major depressive disorder (MDD) or schizophrenia.

RESULTS

Parkinson's disease was commoner in bipolar disorder compared to all three cohorts (odds ratios [OR] ranging from 1.26 to 2.65). Dementia incidence was greater in bipolar disorder than in mixed disorders (OR = 1.61) or MDD (OR = 1.40), but not different from schizophrenia (OR = 0.96). Cerebrovascular disease and stroke were commoner in bipolar disorder than in schizophrenia (OR = 1.35) or mixed disorders (OR = 1.20) and equivocally raised compared to MDD. Results were robust to a wide range of confounding demographic, diagnostic and medication risk factors for neurodegenerative disorders.

CONCLUSIONS

Bipolar disorder confers an elevated risk for developing neurodegenerative disorders and cerebrovascular disease compared to other major adult psychiatric disorders. The results cannot be attributed to recognised confounders. The results are consistent with neuroprogressive views of bipolar disorder. The underlying mechanisms remain to be discovered.

Valproate reverses mania-like behaviors in mice via preferential targeting of HDAC2

Valproate (VPA) has been used in the treatment of bipolar disorder since the 1990s. However, the therapeutic targets of VPA have remained elusive. Here we employ a preclinical model to identify the therapeutic targets of VPA. We find compounds that inhibit histone deacetylase proteins (HDACs) are effective in normalizing manic-like behavior, and that class I HDACs (e.g., HDAC1 and HDAC2) are most important in this response. Using an RNAi approach, we find that HDAC2, but not HDAC1, inhibition in the ventral tegmental area (VTA) is sufficient to normalize behavior. Furthermore, HDAC2 overexpression in the VTA prevents the actions of VPA. We used RNA sequencing in both mice and human induced pluripotent stem cells (iPSCs) derived from bipolar patients to further identify important molecular targets. Together, these studies identify HDAC2 and downstream targets for the development of novel therapeutics for bipolar mania.

Is being born in spring significantly associated with early-onset bipolar affective disorder? A case-control study

Few studies have investigated relationships between birth season and early-onset bipolar affective disorder (BAD) in young adults. In the current study, birth season was compared in patients with early-onset BAD and in sex-matched and age-matched controls. A total of 957 patients aged <25 years of age from three hospitals in the North China Plain region were enrolled in the study. Sex-matched and age-matched control group data were collected in universities and schools via questionnaires. The R*C chi-square test was used to assess distributional differences in season of birth both in the patient and control group. A binary logistic regression model adjusted for age and sex was used to evaluate associations between season of birth and BAD. Using spring as the reference season, BAD patients showed significantly lower odds ratios of being born in any other season. There were associations between birth season and early-onset BAD, and early-onset BAD patients were more likely to have been born in spring. These data have implications for future disease prevention strategies and future research.

Novel loci and potential mechanisms of major depressive disorder, bipolar disorder, and schizophrenia

Different psychiatric disorders share genetic relationships and pleiotropic loci to certain extent. We integrated and analyzed datasets related to major depressive disorder (MDD), bipolar disorder (BIP), and schizophrenia (SCZ) from the Psychiatric Genomics Consortium using multitrait analysis of genome-wide association analysis (MTAG). MTAG significantly increased the effective sample size from 99,773 to 119,754 for MDD, from 909,061 to 1,450,972 for BIP, and from 856,677 to 940,613 for SCZ. We discovered 7, 32, and 43 novel lead single nucleotide polymorphisms (SNPs) and 1, 6, and 3 novel causal SNPs for MDD, BIP, and SCZ, respectively, after fine-mapping. We identified rs8039305 in the FURIN gene as a novel pleiotropic locus across the three disorders. We performed marker analysis of genomic annotation (MAGMA) and Hi-C-coupled MAGMA (H-MAGMA) based gene-set analysis and identified 101 genes associated with the three disorders, which were enriched in the regulation of postsynaptic membranes, postsynaptic membrane dopaminergic synapses, and Notch signaling pathway. Next, we performed Mendelian randomization analysis using different tools and detected a causal effect of BIP on SCZ. Overall, we demonstrated the usage of combined genome-wide association studies summary statistics for exploring potential novel mechanisms of the three psychiatric disorders, providing an alternative approach to integrate publicly available summary data.

Schizophrenia and bipolar disorder are associated with opposite brain reward anticipation-associated response

Blunted and exaggerated neuronal response to rewards are hypothesized to be core features of schizophrenia spectrum disorders (SZ) and bipolar disorder (BD), respectively. Nonetheless, direct tests of this hypothesis, in which response between SZ and BD is compared in the same study, are lacking. Here we examined the functional correlates of reward processing during the Incentivized Control Engagement Task (ICE-T) using 3T fMRI. Reward-associated activation was examined in 49 healthy controls (HCs), 52 recent-onset individuals with SZ, and 22 recent-onset individuals with Type I BD using anterior cingulate (ACC), anterior insula, and ventral striatal regions of interest. Significant group X reward condition (neutral vs. reward) interactions were observed during reward anticipation in the dorsal ACC (F(2,120) = 4.21, P = 0.017) and right insula (F(2,120) = 4.77, P = 0.010). The ACC interaction was driven by relatively higher activation in the BD group vs. HCs (P = 0.007) and vs. individuals with SZ (P = 0.010). The insula interaction was driven by reduced activation in the SZ group relative to HCs (P = 0.018) and vs. people with BD (P = 0.008). A composite of reward anticipation-associated response across all associated ROIs also differed significantly by diagnosis (F(1,120) = 5.59, P = 0.02), BD > HC > SZ. No effects of group or group X reward interactions were observed during reward feedback. These results suggest that people with SZ and BD have opposite patterns of activation associated with reward anticipation but not reward receipt. Implications of these findings in regard to Research Domain Criteria-based classification of illness and the neurobiology of reward in psychosis are discussed.