The pharmacological treatment of bipolar disorder: the question of modern advances

Why lithium should be used in patients with bipolar disorder? A scoping review and an expert opinion paper

INTRODUCTION

Lithium treatment is considered the gold standard for the long-term management of bipolar disorder and recurrent unipolar depression. It is also extremely effective in other psychiatric conditions characterized by impulsivity and aggression, and for the prevention of suicidal behaviours.

AREAS COVERED

This paper provides a scoping review and an expert commentary regarding the use of lithium in adult patients. Available information about efficacy, tolerability, dosing, and switching is analyzed, and the strategies that may be most useful in real-world clinical settings are highlighted.

EXPERT OPINION

Lithium is effective on different domains of bipolar disorder, including the long-term prevention of recurrences of affective episodes, management of acute mania as well as in the prophylaxis of all affective episodes. Lithium has been defined a 'forgotten drug,' since its use in routine clinical practice has been declined over the last 20 or 30 years. Reasons for this trend include lack of adequate training on the management of lithium side effects. Considering its efficacy, use of lithium in ordinary clinical practice should be promoted. Several strategies, such as using slow-release formulations, can be easily implemented in order to minimize lithium side effects and improve its tolerability profile.

A systematic review and meta-analysis of maintenance treatment for psychotic depression

PURPOSE

To perform a systematic review on the use of maintenance treatment to prevent relapse and recurrence in patients with psychotic unipolar or bipolar depression.

METHODS

We conducted an electronic search in December 2019 (and an updated search in July 2021) of four databases (PubMed, Embase, PsycINFO, and Cochrane) to identify controlled studies comparing the relapse rates of patients receiving maintenance treatment for psychotic unipolar depression and psychotic bipolar depression. A meta-analysis was made that included three studies comparing antidepressant (AD) and antipsychotic (AP) combination therapy with AD monotherapy. We used the GRADE tool to assess the quality of evidence.

RESULTS

We included five randomized controlled trials fulfilling the inclusion criteria, making three comparisons: (a) AD + AP versus AD monotherapy; (b) AD + AP versus AP monotherapy; (c) AD + electroconvulsive therapy versus AD monotherapy. The included studies only examined patients with psychotic unipolar depression. The largest included study reported a statistically significant advantage of AD + AP compared with AD monotherapy. We made a meta-analysis of the three studies comparing AD + AP combination therapy with AD monotherapy, which included 195 patients and 56 events. The meta-analysis did not show a statistically significant difference between these treatments.

CONCLUSIONS

Contrary to the finding of the largest study, we did not find a statistically significant difference between AD + AP combination therapy and AD monotherapy in the meta-analysis. There is insufficient evidence to support the superiority of any treatment modality as maintenance treatment for psychotic depression. Further studies are required.

Lithium-Associated Hyperparathyroidism Followed by Catatonia

Objective

To familiarize the medical community with the less common adverse effects of lithium on parathyroid function, we present a case of lithium-associated hyperparathyroidism followed by the development of new-onset catatonia in a patient with schizoaffective disorder.

Methods

To allow for the safe resumption of lithium, the patient received laboratory screening of serum lithium, blood urea nitrogen, serum creatinine, calcium, and thyroid-stimulating hormone levels. The hypercalcemia was evaluated by measuring parathyroid hormone (PTH), ionized calcium, and 25-hydroxy vitamin D levels.

Results

A 58-year-old man with longstanding schizoaffective disorder was admitted for worsening psychotic symptoms following noncompliance with his risperidone and lithium regimen. Exploratory laboratory tests (hospital day 5) showed an elevated PTH level of 72 (reference, 15-65) pg/mL, ionized calcium level of 1.4 (reference, 1.03-1.23) mmol/mL, and a serum calcium level of 11.3 (reference, 8.4-10.5) mg/dL. After the discontinuation of lithium (day 6), anergia (day 7), mutism, and posturing (day 10) developed. Worsening catatonic symptoms of negativism and poor oral intake necessitated dehydration management with intravenous isotonic saline (day 24). The hypercalcemia persisted for 6 weeks. Treatment with cinacalcet (day 43) rapidly normalized the serum calcium levels (day 44). The catatonia, depression, and psychosis began resolving when clozapine (day 50) and electroconvulsive therapy (day 59) were initiated. PTH levels did not normalize until day 82.

Conclusion

This report describes a case of prolonged hyperparathyroidism and hypercalcemia following treatment with lithium. Catatonia is unusual in patients with lithium-associated hyperparathyroidism but this report suggests that in settings yet to be determined, it is related to hypercalcemia of this syndrome.

Environmental pollution is associated with increased risk of psychiatric disorders in the US and Denmark

The search for the genetic factors underlying complex neuropsychiatric disorders has proceeded apace in the past decade. Despite some advances in identifying genetic variants associated with psychiatric disorders, most variants have small individual contributions to risk. By contrast, disease risk increase appears to be less subtle for disease-predisposing environmental insults. In this study, we sought to identify associations between environmental pollution and risk of neuropsychiatric disorders. We present exploratory analyses of 2 independent, very large datasets: 151 million unique individuals, represented in a United States insurance claims dataset, and 1.4 million unique individuals documented in Danish national treatment registers. Environmental Protection Agency (EPA) county-level environmental quality indices (EQIs) in the US and individual-level exposure to air pollution in Denmark were used to assess the association between pollution exposure and the risk of neuropsychiatric disorders. These results show that air pollution is significantly associated with increased risk of psychiatric disorders. We hypothesize that pollutants affect the human brain via neuroinflammatory pathways that have also been shown to cause depression-like phenotypes in animal studies.

Attitudes toward antipsychotic treatment among patients with bipolar disorders and their clinicians: a systematic review

INTRODUCTION

Antipsychotics are recommended as first-line therapy for acute mania and maintenance treatment of bipolar disorder; however, published literature suggests their real-world use remains limited. Understanding attitudes toward these medications may help identify barriers and inform personalized therapy. This literature review evaluated patient and clinician attitudes toward the use of antipsychotics for treating bipolar disorder.

MATERIALS AND METHODS

A systematic search of the Cochrane Library, Ovid MEDLINE, Embase, and BIOSIS Previews identified English language articles published between January 1, 2000, and June 15, 2016, that reported attitudinal data from patients, health care professionals, or caregivers; treatment decision-making; or patient characteristics that predicted antipsychotic use for bipolar disorder. Results were analyzed descriptively.

RESULTS

Of the 209 references identified, 11 met the inclusion criteria and were evaluated. These articles provided attitudinal information from 1,418 patients with bipolar disorder and 1,282 treating clinicians. Patients' attitudes toward antipsychotics were generally positive. Longer duration of clinical stability was associated with positive attitudes. Implementation of psychoeducational and adherence enhancement strategies could improve patient attitudes. Limited data suggest clinicians' perceptions of antipsychotic efficacy and tolerability may have the greatest impact on their prescribing patterns. Because the current real-world evidence base is inadequate, clinician attitudes may reflect a relative lack of experience using antipsychotics in patients with bipolar disorder.

CONCLUSION

Although data are very limited, perceived tolerability and efficacy concerns shape both patient and clinician attitudes toward use of antipsychotic drugs in bipolar disorder. Additional studies are warranted.

A population-based study of the comparative effectiveness of second-generation antipsychotics vs older antimanic agents in bipolar disorder

OBJECTIVES

Numerous antimanic treatments have been introduced over the past two decades, particularly second-generation antipsychotics (SGAs). However, it is not clear whether such newer agents provide any advantage over older treatments.

METHODS

A historical cohort design investigated the nationwide population of outpatients with bipolar disorder treated in the Department of Veterans Affairs who were newly initiated on an antimanic agent between 2003 and 2010 (N=27 727). The primary outcome was likelihood of all-cause hospitalization during the year after initiation, controlling for numerous demographic, clinical, and treatment characteristics. Potential correlates of effect were explored by investigating time to initiation of a second antimanic agent or antidepressant.

RESULTS

After control for covariates, those initiated on lithium or valproate monotherapy, compared to those beginning SGA monotherapy, were significantly less likely to be hospitalized, had a longer time to hospitalization, and had fewer hospitalizations in the subsequent year. Those on combination treatment had a significantly higher likelihood of hospitalization, although they also had a longer time to addition of an additional antimanic agent or antidepressant.

CONCLUSIONS

The present analysis of a large and unselected nationwide population provides important complementary data to that from controlled trials. Although various mechanisms may be responsible for the results, the data support the utilization of lithium or valproate, rather than SGAs, as the initial antimanic treatment in bipolar disorder. A large-scale, prospective, randomized, pragmatic clinical trial comparing the initiation of SGA monotherapy to that of lithium or valproate monotherapy is a logical next step.

Neuroleptic Malignant Syndrome Associated with Lithium Toxicity

Neuroleptic Malignant Syndrome (NMS) is an idiosyncratic and potentially life-threatening reaction to neuroleptic drugs. Lithium is a first-line mood stabilizer used in the treatment and prophylaxis of bipolar disorder. There are several case reports of lithium-associated NMS, but only when it was given in combination with antipsychotics. Therefore, the possibility of NMS being secondary to the antipsychotics could not be ruled out in those cases. Here we present a case of lithium-induced NMS in a patient who was not being treated concomitantly with any other agent known to cause NMS. The patient, a 74-year-old female with a 30-year history of bipolar affective disorder, was admitted to the emergency room of the All India Institute of Medical Sciences, New Delhi, with history of high fever and generalized weakness for 10 days before the admission. NMS was established based the presence of three cardinal symptoms. She was started on intravenous fluids to correct her sodium levels slowly and requested to follow-up at the psychiatry clinic.

Hydrogel-forming microneedle arrays: Potential for use in minimally-invasive lithium monitoring

We describe, for the first time, hydrogel-forming microneedle (s) (MN) arrays for minimally-invasive extraction and quantification of lithium in vitro and in vivo. MN arrays, prepared from aqueous blends of hydrolysed poly(methyl-vinylether-co-maleic anhydride) and crosslinked by poly(ethyleneglycol), imbibed interstitial fluid (ISF) upon skin insertion. Such MN were always removed intact. In vitro, mean detected lithium concentrations showed no significant difference following 30min MN application to excised neonatal porcine skin for lithium citrate concentrations of 0.9 and 2mmol/l. However, after 1h application, the mean lithium concentrations extracted were significantly different, being appropriately concentration-dependent. In vivo, rats were orally dosed with lithium citrate equivalent to 15mg/kg and 30mg/kg lithium carbonate, respectively. MN arrays were applied 1h after dosing and removed 1h later. The two groups, having received different doses, showed no significant difference between lithium concentrations in serum or MN. However, the higher dosed rats demonstrated a lithium concentration extracted from MN arrays equivalent to a mean increase of 22.5% compared to rats which received the lower dose. Hydrogel-forming MN clearly have potential as a minimally-invasive tool for lithium monitoring in outpatient settings. We will now focus on correlation between serum and MN lithium concentrations.

The Ascendancy of Second-Generation Antipsychotics as Frontline Antimanic Agents

INTRODUCTION

Knowledge of the factors affecting the adoption of new medications can enhance mental health care and guide quality improvement and policy development. Food and Drug Administration indications for treating bipolar disorder with several second-generation antipsychotics (SGAs) in the 2000s represent an opportunity to identify factors that impact the spread of a then-innovative treatment through a new population.

METHODS

Analysis of Department of Veterans Affairs administrative data identified the population of 170,811 veterans diagnosed with bipolar disorder from 2003 to 2010. We analyzed time trends and predictors of antimanic choice (SGA vs other) among the 40,512 outpatients with bipolar disorder who initiated their first VA outpatient antimanic prescription, using multinomial logistic regression in month-by-month analyses. We conducted classwise analyses and investigated prespecified predictors among specific agents.

RESULTS

In classwise analyses, SGAs supplanted lithium, valproate, and carbamazepine/oxcarbazepine as the most commonly initiated antimanics by 2007. Psychosis, but not other indices of severity, predicted SGA initiation. Demographic analyses did not identify substantial disparities in initiation of SGAs. Drug-specific analyses revealed some consideration of medical comorbidities in choosing among specific antimanic agents, although effect sizes were small. Most patients initiating an antimanic had received an antidepressant in the previous year.

DISCUSSION

Second-generation antipsychotics quickly became the frontline antimanic treatment for bipolar disorder, although antidepressants most commonly predated antimanic prescriptions. Second-generation antipsychotics were used for a broad range of patients rather than being restricted to a severely ill subpopulation. The modest association of antimanic choice with relevant medical comorbidities suggests that continued attention to quality prescribing practices is warranted.

Targeting renal purinergic signalling for the treatment of lithium-induced nephrogenic diabetes insipidus

Lithium still retains its critical position in the treatment of bipolar disorder by virtue of its ability to prevent suicidal tendencies. However, chronic use of lithium is often limited by the development of nephrogenic diabetes insipidus (NDI), a debilitating condition. Lithium-induced NDI is due to resistance of the kidney to arginine vasopressin (AVP), leading to polyuria, natriuresis and kaliuresis. Purinergic signalling mediated by extracellular nucleotides (ATP/UTP), acting via P2Y receptors, opposes the action of AVP on renal collecting duct (CD) by decreasing the cellular cAMP and thus AQP2 protein levels. Taking a cue from this phenomenon, we discovered the potential involvement of ATP/UTP-activated P2Y2 receptor in lithium-induced NDI in rats and showed that P2Y2 receptor knockout mice are significantly resistant to Li-induced polyuria, natriuresis and kaliuresis. Extension of these studies revealed that ADP-activated P2Y12 receptor is expressed in the kidney, and its irreversible blockade by the administration of clopidogrel bisulphate (Plavix(®)) ameliorates Li-induced NDI in rodents. Parallel in vitro studies showed that P2Y12 receptor blockade by the reversible antagonist PSB-0739 sensitizes CD to the action of AVP. Thus, our studies unravelled the potential beneficial effects of targeting P2Y2 or P2Y12 receptors to counter AVP resistance in lithium-induced NDI. If established in further studies, our findings may pave the way for the development of better and safer methods for the treatment of NDI by bringing a paradigm shift in the approach from the current therapies that predominantly counter the anti-AVP effects to those that enhance the sensitivity of the kidney to AVP action.

Attenuation of lithium-induced natriuresis and kaliuresis in P2Y₂ receptor knockout mice

Whole body knockout (KO) of the P2Y₂ receptor (P2Y₂R) results in enhanced vasopressin V2 receptor activity and increased renal Na⁺ conservation. We hypothesized that P2Y₂R KO mice would be less sensitive to lithium-induced natriuresis and kaliuresis due to attenuated downregulation of one or more of the major renal Na⁺ or K⁺ transporter/channel proteins. KO and wild-type (WT) mice were fed a control or lithium-added diet (40 mmol/kg food) for 14 days. Lithium-induced natriuresis and kaliuresis were significantly (~25%) attenuated in KO mice. The subunits of the epithelial Na⁺ channel (ENaC) were variably affected by lithium and genotype, but, overall, medullary levels were decreased substantially by lithium (15-60%) in both genotypes. In contrast, cortical, β-, and γ-ENaC were increased by lithium (~50%), but only in WT mice. Moreover, an assessment of ENaC activity by benzamil sensitivity suggested that lithium increased ENaC activity in WT mice but in not KO mice. In contrast, medullary levels of Na⁺-K⁺-2Cl⁻ cotransporter 2 and cortical levels of the renal outer medullary K⁺ channel were not downregulated by lithium and were significantly (15-76%) higher in KO mice under both dietary conditions. In addition, under control conditions, tissue osmolality of the inner medulla as well as furosemide sensitivity were significantly higher in KO mice versus WT mice. Therefore, we suggest that increased expression of these proteins, particularly in the control state, reduces Na⁺ delivery to the distal nephron and provides a buffer to attenuate collecting duct-mediated natriuresis and kaliuresis. Additional studies are warranted to explore the potential therapeutic benefits of purinergic antagonism.

Lithium: a versatile tool for understanding renal physiology

By virtue of its unique interactions with kidney cells, lithium became an important research tool in renal physiology and pathophysiology. Investigators have uncovered the intricate relationships of lithium with the vasopressin and aldosterone systems, and the membrane channels or transporters regulated by them. While doing so, their work has also led to 1) questioning the role of adenylyl cyclase activity and prostaglandins in lithium-induced suppression of aquaporin-2 gene transcription; 2) unraveling the role of purinergic signaling in lithium-induced polyuria; and 3) highlighting the importance of the epithelial sodium channel (ENaC) in lithium-induced nephrogenic diabetes insipidus (NDI). Lithium-induced remodeling of the collecting duct has the potential to shed new light on collecting duct remodeling in disease conditions, such as diabetes insipidus. The finding that lithium inhibits glycogen synthase kinase-3β (GSK3β) has opened an avenue for studies on the role of GSK3β in urinary concentration, and GSK isoforms in renal development. Finally, proteomic and metabolomic profiling of the kidney and urine in rats treated with lithium is providing insights into how the kidney adapts its metabolism in conditions such as acquired NDI and the multifactorial nature of lithium-induced NDI. This review provides state-of-the-art knowledge of lithium as a versatile tool for understanding the molecular physiology of the kidney, and a comprehensive view of how this tool is challenging some of our long-standing concepts in renal physiology, often with paradigm shifts, and presenting paradoxical situations in renal pathophysiology. In addition, this review points to future directions in research where lithium can lead the renal community.

Commentary on a recent review of lithium toxicity: what are its implications for clinical practice?

A recent paper by McKnight et al. in The Lancet has provided the first formal meta-analysis of the more common adverse reactions to lithium. The authors analyzed 385 studies and focused mainly on the harmful effects of lithium on the kidney, the thyroid and parathyroid glands, body weight, skin and congenital malformations. Their contribution is important and welcome, but as a guide for practice, it needs to be complemented by other relevant observations and individual patient-focused perspectives.The findings from that meta-analysis somewhat underestimate the renal side-effects, and distort to some degree or exclude other adverse effects. The glomerular filtration rate is reduced but not more than 0 to 5 ml/min/year of observation; this may not fully reflect the present state of knowledge. A quarter of patients in the study had abnormalities of the thyroid and/or parathyroid gland, and lithium was found to increase body weight significantly less than did olanzapine. Unfortunately, the authors did not consider the observations from spontaneous reporting systems, which may have changed the picture.We feel that some specific limitations of the study were related to the inclusion of patients regardless of adequacy of treatment, quality of monitoring, drug combinations, age and sex, and stabilization response.

Comparison of three a-priori models in the prediction of serum lithium concentration

Context:

Mathematical models are valuable for optimizing drug dose and dosing regimens.

Aims:

To compare the precision and bias of three a-priori methods in the prediction of serum level of lithium in patients with bipolar disorder, and to determine their sensitivity and specificity in detecting serum lithium levels outside the therapeutic range.

Settings and Design:

Hospital-based, retrospective study.

Materials and Methods:

In a retrospective study of 31 in-patients, the serum level of lithium was calculated using three different a-priori methods. Mean Prediction Error was used as a measure of bias while Mean Absolute Error and Root Mean Squared Error were used as a measure of precision. The sensitivity and specificity of the methods was calculated.

Results:

All three models underestimated serum lithium level. Precision was best with the model described by Pepin et al., while bias of prediction was the least with the method of Abou Auda et al. The formula by Pepin et al. was able to predict serum lithium level with a mean error of 36.57%. The sensitivity and specificity of the models in identifying serum lithium levels outside the therapeutic range was 80% and 76.19% for Pepin et al., 90% and 74.19% for Zetin et al., and 90% and 66.67% for Abou-Auda et al., respectively.

Conclusion:

The study demonstrates the difference in precision and bias of three a-priori methods, with no one method being superior to the other in the prediction of serum concentration.

Genetic deletion of the P2Y2 receptor offers significant resistance to development of lithium-induced polyuria accompanied by alterations in PGE2 signaling

Lithium (Li)-induced polyuria is due to resistance of the medullary collecting duct (mCD) to the action of arginine vasopressin (AVP), apparently mediated by increased production of PGE(2). We previously reported that the P2Y(2) receptor (P2Y(2)-R) antagonizes the action of AVP on the mCD and may play a role in Li-induced polyuria by enhancing the production of PGE(2) in mCD. Hence, we hypothesized that genetic deletion of P2Y(2)-R should ameliorate Li-induced polyuria. Wild-type (WT) or P2Y(2)-R knockout (KO) mice were fed normal or Li-added diets for 14 days and euthanized. Li-induced polyuria, and decreases in urine osmolality and AQP2 protein abundance in the renal medulla, were significantly less compared with WT mice despite the lack of differences in Li intake or terminal serum or inner medullary tissue Li levels. Li-induced increased urinary excretion of PGE(2) was not affected in KO mice. However, prostanoid EP(3) receptor (EP3-R) protein abundance in the renal medulla of KO mice was markedly lower vs. WT mice, irrespective of the dietary regimen. The protein abundances of other EP-Rs were not altered across the groups irrespective of the dietary regimen. Ex vivo stimulation of mCD with PGE(2) generated significantly more cAMP in Li-fed KO mice (130%) vs. Li-fed WT mice (100%). Taken together, these data suggest 1) genetic deletion of P2Y(2)-R offers significant resistance to the development of Li-induced polyuria; and 2) this resistance is apparently due to altered PGE(2) signaling mediated by a marked decrease in EP3-R protein abundance in the medulla, thus attenuating the EP3-mediated decrease in cAMP levels in mCD.

Lithium in neuropsychiatry: a 2010 update

OBJECTIVES. More than 60 years have passed since the introduction of lithium into modern psychiatry and special issues of Bipolar Disorders in 2009 and Neuropsychobiology in 2010 were devoted to this anniversary. Notwithstanding such a long tradition, a number of key articles on the neuropsychiatric aspects of lithium have appeared in recent years. METHODS. This update was based on the most important original papers and reviews on lithium published in recent years. The main topics were the efficacy of lithium in mood disorders, with a special focus on cognitive functions, the neuroprotective effects of this ion and the potential of using lithium in neurology. RESULTS. Clinical studies and reviews point to lithium being still a cornerstone for the prophylaxis of mood disorders, especially bipolar. The pro-cognitive and antisuicidal properties of lithium have been confirmed as an augmentation of antidepressants in treatment-resistant depression. The neuroprotective effects of lithium have been evidenced in both experimental research and in clinical studies using brain imaging. The possible use of lithium in the prophylaxis of dementia and in neurodegenerative disorders, such as Huntington's disease and amyotrophic lateral sclerosis is discussed. CONCLUSIONS. Although not promoted by pharmaceutical companies, lithium remains a highly important drug in neuropsychiatry.

Synaptic Wnt signaling-a contributor to major psychiatric disorders?

Wnt signaling is a key pathway that helps organize development of the nervous system. It influences cell proliferation, cell fate, and cell migration in the developing nervous system, as well as axon guidance, dendrite development, and synapse formation. Given this wide range of roles, dysregulation of Wnt signaling could have any number of deleterious effects on neural development and thereby contribute in many different ways to the pathogenesis of neurodevelopmental disorders. Some major psychiatric disorders, including schizophrenia, bipolar disorder, and autism spectrum disorders, are coming to be understood as subtle dysregulations of nervous system development, particularly of synapse formation and maintenance. This review will therefore touch on the importance of Wnt signaling to neurodevelopment generally, while focusing on accumulating evidence for a synaptic role of Wnt signaling. These observations will be discussed in the context of current understanding of the neurodevelopmental bases of major psychiatric diseases, spotlighting schizophrenia, bipolar disorder, and autism spectrum disorder. In short, this review will focus on the potential role of synapse formation and maintenance in major psychiatric disorders and summarize evidence that defective Wnt signaling could contribute to their pathogenesis via effects on these late neural differentiation processes.