Motor symptoms of schizophrenia: is tardive dyskinesia a symptom or side effect? A modern treatment

Investigating the Impacts of Diet, Supplementation, Microbiota, Gut-Brain Axis on Schizophrenia: A Narrative Review

Schizophrenia is a disease with a complex etiology that significantly impairs the functioning of patients. In recent years, there has been increasing focus on the importance of the gut microbiota in the context of the gut-brain axis. In our study, we analyzed data on the gut-brain axis in relation to schizophrenia, as well as the impacts of eating habits, the use of various supplements, and diets on schizophrenia. Additionally, the study investigated the impact of antipsychotics on the development of metabolic disorders, such as diabetes, dyslipidemia, and obesity. There may be significant clinical benefits to be gained from therapies supported by supplements such as omega-3 fatty acids, B vitamins, and probiotics. The results suggest the need for a holistic approach to the treatment of schizophrenia, incorporating both drug therapy and dietary interventions.

Deep Brain Stimulation in the Treatment of Tardive Dyskinesia

Tardive dyskinesia (TD) is a phenomenon observed following the predominantly long-term use of dopamine receptor blockers (antipsychotics) widely used in psychiatry. TD is a group of involuntary, irregular hyperkinetic movements, mainly in the muscles of the face, eyelid, lips, tongue, and cheeks, and less frequently in the limbs, neck, pelvis, and trunk. In some patients, TD takes on an extremely severe form, massively disrupting functioning and, moreover, causing stigmatization and suffering. Deep brain stimulation (DBS), a method used, among others, in Parkinson's disease, is also an effective treatment for TD and often becomes a method of last resort, especially in severe, drug-resistant forms. The group of TD patients who have undergone DBS is still very limited. The procedure is relatively new in TD, so the available reliable clinical studies are few and consist mainly of case reports. Unilateral and bilateral stimulation of two sites has proven efficacy in TD treatment. Most authors describe stimulation of the globus pallidus internus (GPi); less frequent descriptions involve the subthalamic nucleus (STN). In the present paper, we provide up-to-date information on the stimulation of both mentioned brain areas. We also compare the efficacy of the two methods by comparing the two available studies that included the largest groups of patients. Although GPi stimulation is more frequently described in literature, our analysis indicates comparable results (reduction of involuntary movements) with STN DBS.

The critical balance between dopamine D2 receptor and RGS for the sensitive detection of a transient decay in dopamine signal

In behavioral learning, reward-related events are encoded into phasic dopamine (DA) signals in the brain. In particular, unexpected reward omission leads to a phasic decrease in DA (DA dip) in the striatum, which triggers long-term potentiation (LTP) in DA D2 receptor (D2R)-expressing spiny-projection neurons (D2 SPNs). While this LTP is required for reward discrimination, it is unclear how such a short DA-dip signal (0.5-2 s) is transferred through intracellular signaling to the coincidence detector, adenylate cyclase (AC). In the present study, we built a computational model of D2 signaling to determine conditions for the DA-dip detection. The DA dip can be detected only if the basal DA signal sufficiently inhibits AC, and the DA-dip signal sufficiently disinhibits AC. We found that those two requirements were simultaneously satisfied only if two key molecules, D2R and regulators of G protein signaling (RGS) were balanced within a certain range; this balance has indeed been observed in experimental studies. We also found that high level of RGS was required for the detection of a 0.5-s short DA dip, and the analytical solutions for these requirements confirmed their universality. The imbalance between D2R and RGS is associated with schizophrenia and DYT1 dystonia, both of which are accompanied by abnormal striatal LTP. Our simulations suggest that D2 SPNs in patients with schizophrenia and DYT1 dystonia cannot detect short DA dips. We finally discussed that such psychiatric and movement disorders can be understood in terms of the imbalance between D2R and RGS.

Long-Term Follow-Up of 12 Patients Treated with Bilateral Pallidal Stimulation for Tardive Dystonia

Tardive dystonia (TD) is a side effect of prolonged dopamine receptor antagonist intake. TD can be a chronic disabling movement disorder despite medical treatment. We previously demonstrated successful outcomes in six patients with TD using deep brain stimulation (DBS); however, more patients are needed to better understand the efficacy of DBS for treating TD. We assessed the outcomes of 12 patients with TD who underwent globus pallidus internus (GPi) DBS by extending the follow-up period of previously reported patients and enrolling six additional patients. All patients were refractory to pharmacotherapy and were referred for surgical intervention by movement disorder neurologists. In all patients, DBS electrodes were implanted bilaterally within the GPi under general anesthesia. The mean ages at TD onset and surgery were 39.2 ± 12.3 years and 44.6 ± 12.3 years, respectively. The Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS) performed the preoperative and postoperative evaluations. The average BFMDRS improvement rate at 1 month postoperatively was 75.6 ± 27.6% (p < 0.001). Ten patients were assessed in the long term (78.0 ± 50.4 months after surgery), and the long-term BFMDRS improvement was 78.0 ± 20.4%. Two patients responded poorly to DBS. Both had a longer duration from TD onset to surgery and older age at surgery. A cognitive and psychiatric decline was observed in the oldest patients, while no such decline ware observed in the younger patients. In most patients with TD, GPi-DBS could be a beneficial therapeutic option for long-term relief of TD.

Tardive syndromes

Dopamine receptor-blocking antipsychotics, first introduced into clinical practice in 1952, were hailed as a panacea in the treatment of a number of psychiatric disorders. However, within 5 years, this notion was to be shattered by the recognition of both acute and chronic drug-induced movement disorders which can accompany their administration. Tardive syndromes, denoting the delayed onset of movement disorders following administration of dopamine receptor-blocking (and also other) drugs, have diverse manifestations ranging from the classic oro-bucco-lingual dyskinesia, through dystonic craniocervical and trunk posturing, to abnormal breathing patterns. Although tardive syndromes have been an important part of movement disorder clinical practice for over 60 years, their pathophysiologic basis remains poorly understood and the optimal treatment approach remains unclear. This review summarises the current knowledge relating to these syndromes and provides clinicians with pragmatic, clinically focused guidance to their management.

Tardive dyskinesia: motor system impairments, cognition and everyday functioning

The recent approval of treatments for tardive dyskinesia (TD) has rekindled interest in this chronic and previously recalcitrant condition. A large proportion of patients with chronic mental illness suffer from various degrees of TD. Even the newer antipsychotics constitute a liability for TD, and their liberal prescription might lead to emergence of new TD in patient populations previously less exposed to antipsychotics, such as those with depression, bipolar disorder, autism, or even attention deficit hyperactivity disorder. The association of TD with activity limitations remains poorly understood. We review potential new avenues of assessing the functional sequelae of TD, such as the performance of instrumental activities of daily living, residential status, and employment outcomes. We identify several mediating aspects, including physical performance measures and cognition, that may represent links between TD and everyday performance, as well as potential treatment targets.

Tardive dyskinesia: Epidemiology

The term tardive syndrome (TS) encompasses a few different phenomenologic conditions, some of which occur in isolation and others in association with each other. This, along with the unusual confound for a drug side effect, in which increased use of the drug improves the problem, and the need for most patients to continue taking the offending drug, makes understanding the epidemiology difficult and unreliable. While the change from the "first generation" to the "second generation" of antipsychotic drugs is generally believed to have reduced the incidence of TS, prospective research studies have not supported that contention. Published reports have found point prevalences of 13% with second generation antipsychotics and 32% with first, yet others have found no differences. One study found increasing rates of TS with a 68% prevalence by 25 years, while another found a decreased prevalence over time, due presumably to masking effects of the antipsychotic drugs. Regardless of the possible differences, it is clear that TS remains a significant and common problem associated with almost all antipsychotic drugs. There have also been scattered reports of TS caused by drugs not known to inhibit dopamine receptors. These are reviewed and were found to be often of dubious reliability.

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.

Manual Dexterity in Schizophrenia-A Neglected Clinical Marker?

Impaired manual dexterity is commonly observed in schizophrenia. However, a quantitative description of key sensorimotor components contributing to impaired dexterity is lacking. Whether the key components of dexterity are differentially affected and how they relate to clinical characteristics also remains unclear. We quantified the degree of dexterity in 35 stabilized patients with schizophrenia and in 20 age-matched control subjects using four visuomotor tasks: (i) force tracking to quantify visuomotor precision, (ii) sequential finger tapping to measure motor sequence recall, (iii) single-finger tapping to assess temporal regularity, and (iv) multi-finger tapping to measure independence of finger movements. Diverse clinical and neuropsychological tests were also applied. A patient subgroup (N = 15) participated in a 14-week cognitive remediation protocol and was assessed before and after remediation. Compared to control subjects, patients with schizophrenia showed greater error in force tracking, poorer recall of tapping sequences, decreased tapping regularity, and reduced degree of finger individuation. A composite performance measure discriminated patients from controls with sensitivity = 0.79 and specificity = 0.9. Aside from force-tracking error, no other dexterity components correlated with antipsychotic medication. In patients, some dexterity components correlated with neurological soft signs, Positive and Negative Syndrome Scale (PANSS), or neuropsychological scores. This suggests differential cognitive contributions to these components. Cognitive remediation lead to significant improvement in PANSS, tracking error, and sequence recall (without change in medication). These findings show that multiple aspects of sensorimotor control contribute to impaired manual dexterity in schizophrenia. Only visuomotor precision was related to antipsychotic medication. Good diagnostic accuracy and responsiveness to treatment suggest that manual dexterity may represent a useful clinical marker in schizophrenia.

Nigella sativa Oil Reduces Extrapyramidal Symptoms (EPS)-Like Behavior in Haloperidol-Treated Rats

The symptoms of Parkinsonism and oral dyskinesia have been showing to be induced by neuroleptics that significantly affect its clinical use. In this study, we investigate whether Nigella sativa-oil (NS) (black cumin seeds)-a traditional medicine used for the seizure treatment in eastern country-may reduce the haloperidol (HAL)-induced extrapyramidal symptoms (EPS)-like behavior in rats. After combine treatment with HAL (1 mg/kg) on NS (0.2 ml/rat), rats displayed a significant decreased EPS-like behavior including movement disorders and oral dyskinesia as compared to controls. Immunohistochemical analysis indicates that NS reduced astrogliosis in caudate and accumbens nuclei. These results suggest that NS may consider as an adjunct to antipsychotics to reduce the EPS-like side effect.

Therapeutic Perspective on Tardive Syndrome with Special Reference to Deep Brain Stimulation

Tardive syndrome (TDS) is a potentially permanent and irreversible hyperkinetic movement disorder caused by exposure to dopamine receptor blocking agents. Guidelines published by the American Academy of Neurology recommend pharmacological first-line treatment for TDS with clonazepam (level B), ginkgo biloba (level B), amantadine (level C), and tetrabenazine (level C). Recently, a class II study provided level C evidence for use of deep brain stimulation (DBS) of the globus pallidus internus (GPi) in patients with TDS. Although the precise pathogenesis of TDS remains to be elucidated, the beneficial effects of GPi-DBS in patients with TDS suggest that the disease may be a basal ganglia disorder. In addition to recent advances in understanding the pathophysiology of TDS, this article introduces the current use of DBS in the treatment of medically intractable TDS.

Effects of antipsychotics, antidepressants and mood stabilizers on risk for physical diseases in people with schizophrenia, depression and bipolar disorder

People with severe mental illness have a considerably shorter lifespan than the general population. This excess mortality is mainly due to physical illness. Next to mental illness-related factors, unhealthy lifestyle, and disparities in health care access and utilization, psychotropic medications can contribute to the risk of physical morbidity and mortality. We systematically reviewed the effects of antipsychotics, antidepressants and mood stabilizers on physical health outcomes in people with schizophrenia, depression and bipolar disorder. Updating and expanding our prior systematic review published in this journal, we searched MEDLINE (November 2009 - November 2014), combining the MeSH terms of major physical disease categories (and/or relevant diseases within these categories) with schizophrenia, major depressive disorder and bipolar disorder, and the three major psychotropic classes which received regulatory approval for these disorders, i.e., antipsychotics, antidepressants and mood stabilizers. We gave precedence to results from (systematic) reviews and meta-analyses wherever possible. Antipsychotics, and to a more restricted degree antidepressants and mood stabilizers, are associated with an increased risk for several physical diseases, including obesity, dyslipidemia, diabetes mellitus, thyroid disorders, hyponatremia; cardiovascular, respiratory tract, gastrointestinal, haematological, musculoskeletal and renal diseases, as well as movement and seizure disorders. Higher dosages, polypharmacy, and treatment of vulnerable (e.g., old or young) individuals are associated with greater absolute (elderly) and relative (youth) risk for most of these physical diseases. To what degree medication-specific and patient-specific risk factors interact, and how adverse outcomes can be minimized, allowing patients to derive maximum benefits from these medications, requires adequate clinical attention and further research.

Tardive dyskinesia (syndrome): Current concept and modern approaches to its management

Tardive dyskinesia is a serious, disabling and potentially permanent, neurological hyperkinetic movement disorder that occurs after months or years of taking psychotropic drugs. The pathophysiology of tardive dyskinesia is complex, multifactorial and still not fully understood. A number of drugs were tried for the management of this motor disturbance, yet until now no effective and standard treatment has been found. It is very disappointing to realize that the introduction of antipsychotics from the second generation has not significantly decreased the prevalence and incidence of tardive dyskinesia. Therefore, the management of this motor disturbance remains an actual topic as well as a challenge for clinicians. This review summarizes recent relevant publications concerning the treatment of tardive dyskinesia.

Tardive Blepharospasm and Meige Syndrome during Treatment with Quetiapine and Olanzapine

Meige syndrome, which has been presented in tardive syndromes, is a form of blepharospasm accompanied by oromandibular dystonia with manifestations over the face, jaw, and neck. A blepharospasm can be induced by antihistamines, dopaminomimetic or sympathomimetic drugs, or long-term exposure to dopamine antagonists. Atypical antipsychotics have less extrapyramidal side effects because of a weak dopamine D2 receptor binding affinity or a strong antagonistic effect to serotonin 5-HT2a receptor and have been known to cause less tardive dyskinesia than typical antipsychotics. Thus, in literature, atypical antipsychotics are recommended for the treatment of psychosis in cases of tardive dyskinesia. The potential risk factors associated with the development of tardive dyskinesia are extrapyramidal symptoms' history, diabetes mellitus, affective disorder, female gender, older age, and long-term therapy with neuroleptics at higher dosages. As reported below, a patient with an affective disorder who had quetiapine-induced oromandibular dystonia and olanzapine-induced Meige syndrome after antipsychotic augmentation in different stages of the disease process was presented.

Antipsychotics-induced tardive syndrome: a retrospective epidemiological study

OBJECTIVES

Only little information of the epidemiology of tardive syndrome in patients using antipsychotics is available. Herein, we aimed to investigate the prevalence and risk factors of antipsychotics-induced tardive syndrome.

METHODS

This study was conducted by means of a retrospective survey. Subjects receiving antipsychotics for more than 6 months, but no other agents that may cause involuntary movements, were consecutively recruited. Tardive syndrome was evaluated in every included subject. Possible confounding medical conditions were carefully ruled out.

RESULTS

Of the 123 included subjects, 35 (28.5%) were found to have at least 1 episode of tardive syndrome. The prevalence of subtypes of tardive syndrome were as follows: tardive dyskinesia, 21.1%; tardive dystonia, 12.5%; tardive tremor, 2.4%; and tardive akathisia, 2.4%. Concurrent physical illness and a history of extrapyramidal symptoms were significant risk factors for tardive syndrome.

CONCLUSIONS

This study showed that antipsychotics may induce various types of tardive syndrome, of which tardive dyskinesia is the most predominant one. Physicians should be aware of this common and distressing adverse effect when using antipsychotics.

New and emerging treatments for symptomatic tardive dyskinesia

The aim of this review is to assess new, emerging, and experimental treatment options for tardive dyskinesia (TD). The methods to obtain relevant studies for review included a MEDLINE search and a review of studies in English, along with checking reference lists of articles. The leading explanatory models of TD development include dopamine receptor supersensitivity, GABA depletion, cholinergic deficiency, neurotoxicity, oxidative stress, changes in synaptic plasticity, and defective neuroadaptive signaling. As such, a wide range of treatment options are available. To provide a complete summary of choices we review atypical antipsychotics along with resveratrol, botulinum toxin, Ginkgo biloba, tetrabenazine, clonazepam, melatonin, essential fatty acids, zonisamide, levetiracetam, branched-chain amino acids, drug combinations, and invasive surgical treatments. There is currently no US Food and Drug Administration-approved treatment for TD; however, prudent use of atypical antipsychotics with routine monitoring remain the cornerstone of therapy, with experimental treatment options available for further management.

Cell-free protein synthesis and purification of human dopamine D2 receptor long isoform

The human dopamine D2 receptor long isoform (D2L) has significant implications in neurological and neuropsychiatric disorders such as Parkinson's disease and schizophrenia. Detailed structural knowledge of this receptor is limited owing to its highly hydrophobic nature, which leads to protein aggregation and host toxicity when expressed in cellular systems. The newly emerging field of cell-free protein expression presents numerous advantages to overcome these challenges. This system utilizes protein synthesis machinery and exogenous DNA to synthesize functional proteins outside of intact cells. This study utilizes two different cell-free systems for the synthesis of human dopamine D2L receptor. These include the Escherichia coli lysate-based system and the wheat-germ lysate-based system. The bacterial cell-free method used pET 100/D-TOPO vector to synthesize hexa-histidine-tagged D2L receptor using a dialysis bag system; the resulting protein was purified using nickel-nitrilotriacetic acid affinity resin. The wheat germ system used pEU-glutathione-S-transferase (GST) vector to synthesize GST-tagged D2L receptor using a bilayer translation method; the resulting protein was purified using a GST affinity resin. The presence and binding capacity of the synthesized D2L receptor was confirmed by immunoblotting and radioligand competition assays, respectively. Additionally, in-gel protein sequencing via Nano LC-MS/MS was used to confirm protein synthesis via the wheat germ system. The results showed both systems to synthesize microgram quantities of the receptor. Improved expression of this highly challenging protein can improve research and understanding of the human dopamine D2L receptor.

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

This paper reviews melatonin as an overlooked factor in the developmental etiology and maintenance of schizophrenia; the neuroimmune and oxidative pathophysiology of schizophrenia; specific symptoms in schizophrenia, including sleep disturbance; circadian rhythms; and side effects of antipsychotics, including tardive dyskinesia and metabolic syndrome. Electronic databases, i.e. PUBMED, Scopus and Google Scholar were used as sources for this review using keywords: schizophrenia, psychosis, tardive dyskinesia, antipsychotics, metabolic syndrome, drug side effects and melatonin. Articles were selected on the basis of relevance to the etiology, course and treatment of schizophrenia. Melatonin levels and melatonin circadian rhythm are significantly decreased in schizophrenic patients. The adjunctive use of melatonin in schizophrenia may augment the efficacy of antipsychotics through its anti-inflammatory and antioxidative effects. Further, melatonin would be expected to improve sleep disorders in schizophrenia and side effects of anti-psychotics, such as tardive dyskinesia, metaboilic syndrome and hypertension. It is proposed that melatonin also impacts on the tryptophan catabolic pathway via its effect on stress response and cortisol secretion, thereby impacting on cortex associated cognition, amygdala associated affect and striatal motivational processing. The secretion of melatonin is decreased in schizophrenia, contributing to its etiology, pathophysiology and management. Melatonin is likely to have impacts on the metabolic side effects of anti-psychotics that contribute to subsequent decreases in life-expectancy.