The effects of lithium carbonate on healthy volunteers: mood stabilization?

Bipolar Disorder and Cognitive Dysfunction: A Complex Link

The aim of this article was to describe the current evidence regarding phenomenon of cognitive functioning and dementia in bipolar disorder (BD). Cochrane Library and PubMed searches were conducted for relevant articles, chapters, and books published before 2016. Search terms used included "bipolar disorder," "cognitive dysfunction," and "dementia." At the end of the selection process, 159 studies were included in our qualitative synthesis. As result, cognitive impairments in BD have been previously considered as infrequent and limited to the affective episodes. Nowadays, there is evidence of stable and lasting cognitive dysfunctions in all phases of BD, including remission phase, particularly in the following domains: attention, memory, and executive functions. The cause of cognitive impairment in BD raises the question if it subtends a neurodevelopmental or a neurodegenerative process. Impaired cognitive functioning associated with BD may contribute significantly to functional disability, in addition to the distorted affective component usually emphasized.

Lithium activates brain phospholipase A2 and improves memory in rats: implications for Alzheimer's disease

Phospholipase A2 (Pla2) is required for memory retrieval, and its inhibition in the hippocampus has been reported to impair memory acquisition in rats. Moreover, cognitive decline and memory deficits showed to be reduced in animal models after lithium treatment, prompting us to evaluate possible links between Pla2, lithium and memory. Here, we evaluated the possible modulation of Pla2 activity by a long-term treatment of rats with low doses of lithium and its impact in memory. Wistar rats were trained for the inhibitory avoidance task, treated with lithium for 100 days and tested for perdurability of long-term memory. Hippocampal samples were used for quantifying the expression of 19 brain-expressed Pla2 genes and for evaluating the enzymatic activity of Pla2 using group-specific radio-enzymatic assays. Our data pointed to a significant perdurability of long-term memory, which correlated with increased transcriptional and enzymatic activities of certain members of the Pla2 family (iPla2 and sPla2) after the chronic lithium treatment. Our data suggest new possible targets of lithium, add more information on its pharmacological activity and reinforce the possible use of low doses of lithium for the treatment of neurodegenerative conditions such as the Alzheimer's disease.

The management of cognitive impairment in bipolar disorder: current status and perspectives

Bipolar disorder (BD) is associated with important cognitive deficits that persist during the periods of remission. Although these deficits seem to play an important role in the functional impairment experienced by bipolar patients, evidence regarding their clinical management is scant. We revised the databases PubMed, MEDLINE, and clinicaltrials.gov, searching for studies focusing on the pharmacological and nonpharmacological treatment of cognitive deficits among bipolar patients. In addition, a manual search of bibliographical cross-references was performed. Currently, there is no Food and Drug Administration-approved pharmacological agent for the management of cognitive deficits in BD. A number of agents have been tested in the treatment of cognitive deficits in BD, with mixed results. Nonpharmacological interventions, such as cognitive remediation and noninvasive brain stimulation techniques, seem promising, but their role has not yet been properly explored among bipolar patients. Additional studies, aiming at evaluating the efficacy of interventions combining cognitive rehabilitation and biological treatments, are highly desirable.

Animal models of bipolar mania: The past, present and future

Bipolar disorder (BD) is the sixth leading cause of disability in the world according to the World Health Organization and affects nearly six million (∼2.5% of the population) adults in the United State alone each year. BD is primarily characterized by mood cycling of depressive (e.g., helplessness, reduced energy and activity, and anhedonia) and manic (e.g., increased energy and hyperactivity, reduced need for sleep, impulsivity, reduced anxiety and depression), episodes. The following review describes several animal models of bipolar mania with a focus on more recent findings using genetically modified mice, including several with the potential of investigating the mechanisms underlying 'mood' cycling (or behavioral switching in rodents). We discuss whether each of these models satisfy criteria of validity (i.e., face, predictive, and construct), while highlighting their strengths and limitations. Animal models are helping to address critical questions related to pathophysiology of bipolar mania, in an effort to more clearly define necessary targets of first-line medications, lithium and valproic acid, and to discover novel mechanisms with the hope of developing more effective therapeutics. Future studies will leverage new technologies and strategies for integrating animal and human data to reveal important insights into the etiology, pathophysiology, and treatment of BD.

The medicalisation of "ups and downs": the marketing of the new bipolar disorder

The concept of bipolar disorder has undergone a transformation over the last two decades. Once considered a rare and serious mental disorder, bipolar disorder is being diagnosed with increasing frequency in Europe and North America, and is suggested to replace many other diagnoses. The current article shows how the modern concept of bipolar disorder has been created in the course of efforts to market new antipsychotics and other drugs for bipolar disorder, to enable these drugs to migrate out of the arena of serious mental disorder and into the more profitable realm of everyday emotional problems. A new and flexible notion of the condition has been created that bears little resemblance to the classical condition, and that can easily be applied to ordinary variations in temperament. The assertion that bipolar disorder is a brain disease arising from a biochemical imbalance helps justify this expansion by portraying drug treatment as targeted and specific, and by diverting attention from the adverse effects and mind-altering properties of the drugs themselves. Childhood behavioural problems have also been metamorphosed into "paediatric bipolar disorder," under the leadership of academic psychiatry, with the assistance of drug company financing. The expansion of bipolar disorder, like depression before it, medicalises personal and social difficulties, and profoundly affects the way people in Western nations conceive of what it means to be human.

Pharmacological approaches in bipolar disorders and the impact on cognition: a critical overview

OBJECTIVE

Historically, pharmacological treatments for bipolar disorders (BD) have been associated with neurocognitive side-effects. We reviewed studies which assessed the impact of several psychopharmacological drugs on the neurocognitive function of BD patients.

METHOD

The PubMed database was searched for studies published between January 1980 and February 2011, using the following terms: bipolar, bipolar disorder, mania, manic episode, or bipolar depression, cross-referenced with cognitive, neurocognitive, or neuropsychological, cross-referenced with treatment.

RESULTS

Despite methodological flaws in the older studies and insufficient research concerning the newer agents, some consistent findings emerged from the review; lithium appears to have definite, yet subtle, negative effects on psychomotor speed and verbal memory. Among the newer anticonvulsants, lamotrigine appears to have a better cognitive profile than carbamazepine, valproate, topiramate, and zonisamide. More long-term studies are needed to better understand the impact of atypical antipsychotics on BD patients' neurocognitive functioning, both in monotherapy and in association with other drugs. Other agents, like antidepressants and cognitive enhancers, have not been adequately studied in BD so far.

CONCLUSION

Pharmacotherapies for BD should be chosen to minimize neurocognitive side-effects, which may already be compromised by the disease process itself. Neurocognitive evaluation should be considered in BD patients to better evaluate treatment impact on neurocognition. A comprehensive neuropsychological evaluation also addressing potential variables and key aspects such as more severe cognitive deficits, comorbidities, differential diagnosis, and evaluation of multiple cognitive domains in longitudinal follow-up studies are warranted.

Differential effects of endogenous lithium on neurobehavioural functioning: a study on auditory evoked potentials

Lithium occurs naturally in food and water. Low environmental concentrations in drinking water are associated with mental illnesses and behavioural offences, and at therapeutic dosages it is used to treat psychiatric (especially affective) disorders, partly by facilitating serotonergic (5-HT) neurotransmission. As little is known about the psychophysiological role of nutritional lithium in the general population, endogenous lithium concentrations were hypothesised to be associated with measurable effects on emotional liability and the loudness dependence (LD) that is proposed as one of the most valid indicators of 5-HT neurotransmission. Auditory evoked potentials of healthy volunteers [N=36] with high (>2.5 microg/l) or low (<1.5 microg/l) lithium serum concentrations were recorded. Emotional liability was assessed using the Brief Symptom Inventory (BSI). Low-lithium levels correlated with Somatisation while correlations between lithium and LD were not significant. Still, LD correlated positively with Paranoid Ideation, negatively with Anxiety and, in the high-lithium group, inversely with further aspects of emotional liability (Depression, Psychological Distress). In conclusion, the effects of low levels of endogenous lithium are associated with emotional liability, and high levels with some protective effects, although findings remain inconclusive regarding LD. Potential benefits of endogenous lithium on neurobehavioural functioning, especially in high-risk individuals, would have public health implications.

Lithium and cognitive enhancement: leave it or take it?

RATIONALE

Lithium is established as an effective treatment of acute mania, bipolar and unipolar depression and as prophylaxis against bipolar disorder. Accumulating evidence is also delineating a neuroprotective and neurotrophic role for lithium. However, its primary effects on cognitive functioning remain ambiguous.

OBJECTIVES

The aim of this paper is to review and combine the relevant translational studies, focusing on the putative cognitive enhancement properties of lithium, specifically on learning, memory, and attention.

DISCUSSION

These properties are also discussed in reference to research demonstrating a protective action of lithium against cognitive deficits induced by various challenges to the nervous system, such as stress, trauma, neurodegenerative disorders, and psychiatric disorders.

CONCLUSIONS

It is suggested on the basis of the evidence that the cognitive effects of lithium are best expressed and should, therefore, be sought under conditions of functional or biological challenge to the nervous system.

Chronic lithium salt treatment reduces CRE/CREB-directed gene transcription and reverses its upregulation by chronic psychosocial stress in transgenic reporter gene mice

The molecular mechanism of action of the mood stabilizer lithium is assumed to involve changes in gene expression leading to neuronal adaptation. The transcription factor CREB (cAMP-responsive element binding protein) regulates the expression of many genes and has been implicated in important brain functions and the action of psychogenic agents. We here investigated the effect of lithium on cAMP-responsive element (CRE)/CREB-mediated gene transcription in the brain, using transgenic reporter mice that express the luciferase reporter gene under the control of four copies of the rat somatostatin gene promoter CRE. Chronic (21 days) but not acute (24 h) treatment with lithium (7.5 mmol/kg) significantly decreased CRE/CREB-directed gene expression in hippocampus, cortex, hypothalamus, and striatum to 60-70%, and likewise reduced CREB phosphorylation. As bipolar disorder is also considered as a stress-related disorder, the effect of lithium was determined in mice submitted to a paradigm for chronic psychosocial stress. As shown before, stress for 25 days significantly increased CRE/CREB-directed gene expression in several brain regions by 100-150%. Treatment of stressed mice with lithium decreased stress-induced CRE/CREB-directed gene expression to control levels in nearly all brain regions and likewise reduced CREB phosphorylation. Chronic lithium treatment induced beta-catenin accumulation and decreased cAMP levels, indicating an inhibitory effect of lithium on glycogen synthase kinase 3 and the adenylate cyclase/protein kinase A signalling cascade, which are known to modulate CREB activity. We here for the first time show that lithium regulates CRE/CREB-directed gene transcription in vivo and suggest CREB as a putative mediator of the neuronal adaptation after chronic lithium treatment.

Role for the Clock gene in bipolar disorder

Nearly all patients with bipolar disorder have severely disrupted circadian rhythms. Treatment with mood stabilizers can restore these daily rhythms, and this is correlated with patient recovery. However, it is still uncertain whether clock abnormalities are the cause of bipolar disorder or if these rhythm disruptions are secondary to alterations in other circuits. Furthermore, the mechanism by which the circadian clock might influence mood is still unclear. With cloning and characterization of the circadian genes and recent advances in molecular biology, we are starting to understand this strong association between circadian rhythms and bipolar disorder. Recent human genetic and mouse behavioral studies indicate that the Clock gene is particularly relevant in the mood disruptions associated with this disorder. Furthermore, it appears that Clock expression outside of the central pacemaker of the suprachiasmatic nucleus (SCN) is involved in mood regulation. In this chapter, the evidence linking circadian rhythms, the Clock gene, and bipolar disorder is discussed, along with the possible biology that underlies this connection.

Enhancing effects of chronic lithium on memory in the rat

BACKGROUND

In spite of recent enrichment of neurochemical and behavioural data establishing a neuroprotective role for lithium, its primary effects on cognitive functioning remain ambiguous. This study examines chronic lithium effects on spatial working memory and long-term retention.

METHODS

In three discrete experiments, rats subjected to 30 daily intraperitoneal injections (2mmol/kg) of lithium (lithium groups: serum lithium=0.5+/-0.4mEq/l, 12h post-injection) or saline (controls) were trained in 0-s delay T-maze alternation and then tested in 30-, 45- and 60-s delay alternation (Experiments 1, 2, 3, respectively). Animals from Experiment 1 were further tested in one-trial step-through passive avoidance under mild shock parameters (0.5mA, 1s). Retention was assessed 6h later. Daily lithium or saline injections continued throughout behavioural testing.

RESULTS

Lithium animals were indistinguishable from controls during 0-delay alternation baseline (Experiments 1-3, accuracy>88%) but showed significantly higher accuracy than controls at 30- and 45-s delays (93% versus 85% and 92% versus 82%, Experiments 1 and 2, respectively). At 60-s delay (Experiment 3) this beneficial effect of lithium was no longer apparent (lithium and control accuracy=78%). In Experiment 4, the shock used did not support 6-h passive avoidance retention in controls, whereas lithium animals showed significant step-through latency increases.

CONCLUSIONS

Chronic lithium enhanced spatial working memory and promoted long-term retention of a weak aversive contingency. The results suggest that lithium may have potential as a cognitive enhancer.

The effects of lithium on cognition: an updated review

RATIONALE

Adverse cognitive effects associated with lithium are often implicated as contributing to vocational and social impairment, as well as medication noncompliance. As impaired cognitive functioning caused by lithium has clear clinical implications, it is important to determine whether evidence for or against impaired cognitive functioning exists in the literature.

OBJECTIVES

An attempt is made to synthesize findings from previous studies, which assess a variety of cognitive domains, to determine whether conclusions can be drawn regarding lithium-associated cognitive impairment. The "reversibility" of neuropsychological impairment following lithium discontinuation and whether lithium administration has negative cumulative effects on cognition were also reviewed.

METHODS

Key word searches on "Medline" and "Psych Info" were completed for clinical articles that investigated the neuropsychological effects of lithium in clinical and normal populations between 1968 and 2000.

RESULTS

Despite methodological flaws, poor replicability and the subtle cognitive effects of lithium, five consistent findings emerged from the review; impairment on tasks of psychomotor speed, impaired functioning in the majority of studies examining verbal memory, no impairment on tasks of visuo-spatial constructional ability or attention/ concentration, and no negative cumulative effect.

CONCLUSIONS

Many patients administered lithium carbonate complained of mental slowness. Lithium carbonate also appeared to have definite, yet subtle, negative effects on psychomotor speed. Studies reviewed also showed a trend toward impaired verbal memory. Recommendations with respect to future research, methodological and statistical problems, and additional clinical implications are presented.

On the meaning and measurement of affective instability: clues from chaos theory

BACKGROUND

"Affective instability" describes affective shifts occurring over hours to days that are associated with clinically significant impairment or distress. Since patients with this condition are clinically "chaotic," we undertook to study affective instability relative to normal affective variability using the tools of chaos theory.

METHODS

Patients and controls generated time series data over 90 days using a visual analog mood scale to capture daily affective means and extremes. The series were analyzed using the Mean Squared Successive Difference (MSSD), Power Spectral Density (PSD), and Fractal Dimension (FD).

RESULTS

Patients demonstrated substantially more variability than controls on the MSSD, but less complexity as measured by the FD. The PSD revealed that power varied with frequency (f) in a 1 [corrected] alpha relationship, wherein the alpha for patients was double that for controls.

CONCLUSIONS

Despite the "chaotic" clinical presentation of affective instability patients, affective instability itself was found to be less complex from a chaos-theoretic perspective than normal affective variability. Of particular interest is the alpha ratio of order 2 between patients and controls seen in both our study and a similar but much longer study of mood in rapid-cycling bipolar disorder; an observation suggesting that pathological affect may be distinguishable from normal affective variability by a scale-invariant parameter.

Lithium: evidence reconsidered

This review examines the evidence for the main current recommendations for lithium use in psychiatry and briefly summarises the literature on its adverse consequences, in an attempt to develop an overall evaluation of its potential role based on available evidence. An introduction to the history of lithium is given because it is suggested that in both the 19th and 20th centuries the social context in which lithium emerged, rather than the quality of the scientific evidence, was decisive in determining its adoption as a treatment.

Effect of pleasant odors on mood of males at midlife: comparison of African-American and European-American men

The purpose of this study was to determine if daily use of colognes could elevate mood in middle-aged men. Sixty men ranging in age from 40 to 55 years participated in the study. Half were European-American and half were African-American. Mood ratings were obtained twice daily for 12 days using the Profile of Mood States questionnaire (POMS). The first 2 days of the experiment were used as baseline information to establish each man's mood prior to the administration of the colognes. The following 10 days of the study consisted of two conditions of 5 days each, the fragrance condition and the placebo condition. Main effects of condition (baseline, fragrance, placebo) were found for all POMS factors including tension, depression, anger, vigor, fatigue, and confusion, as well as for the Total Mood Disturbance score (TMD). The scores for the fragrance condition were significantly better than those for the baseline condition for tension, depression, anger, fatigue, and confusion factors, as well as for the TMD. Also, the scores for the fragrance condition were significantly better than those for the placebo condition for all factors and the TMD. There was a main effect for race, with European-American subjects having significantly worse scores for tension and fatigue and significantly better scores for depression than African-American subjects. An interaction was present between race and condition for the depression, vigor, and confusion factors. The main conclusion of this study was that use of pleasant odors improved the mood of males at midlife.

The effect of pleasant odors and hormone status on mood of women at midlife

The effect of odors on the mood of 56 women ranging in age from 45 to 60 years was determined using the POMS (Profile of Mood States). The 56 subjects were divided into four groups of 14 subjects each on the basis of hormonal status. Group 1 consisted of 14 women who were still menstruating; group 2 consisted of 14 women who were no longer menstruating and taking estrogen; group 3 consisted of 14 women who were no longer menstruating and taking estrogen and progesterone; and, group 4 consisted of 14 women who were no longer menstruating and taking no hormone replacement. Use of pleasant odors significantly improved scores on tension, depression, and confusion factors. In addition, women using estrogen replacement with or without progesterone had better mood scores than those who did not, which is consistent with previous studies.

Mood variability in normal subjects on lithium

To investigate the effect of lithium carbonate on normal volunteers' moods, we randomly assigned 30 subjects to 5 weeks each of placebo and lithium treatment with crossover at midstudy. Lithium levels were maintained during the treatment period at a mean serum level of 0.54 mEq/L. All subjects completed visual analogue mood scales (VAMS) daily throughout the study period; segmented visual analogue scales (SVAS) measuring mood, anxiety, and energy and the Profile of Mood States (POMS) were completed weekly at testing sessions. Neither mean mood nor mood variability as assessed by the delta square (mean square successive difference) differed between placebo and lithium conditions. Segmented visual analogue scale mood ratings were highly correlated with the VAMS and similarly showed no difference between conditions. The self-rated mood variability, however, declined significantly in both experimental conditions as a function of time on study. None of the POMS factors differed between placebo and lithium conditions. These data suggest that lithium, in modest doses administered over 5 weeks, does not have a substantial mood-stabilizing effect in normal subjects.