Does long-term medication with lithium, clozapine or antidepressants prevent or attenuate dementia in bipolar and depressed patients?

Psychiatric Disease as a Potential Risk Factor for Dementia: A Narrative Review

Neurodegenerative disease is a major global health problem with 150 million people predicted to have dementia by 2050. Genetic factors, environmental factors, demographics, and some diseases have been associated with dementia. In addition to associations between diseases such as hypertension and cerebrovascular disease and dementia, emerging findings associate some psychiatric disorders with incident dementia. Because of the high and increasing global prevalence of dementia and the high worldwide prevalence of psychiatric disorders, the primary objective of this narrative review was to evaluate published findings that evaluate the association between bipolar disorder, depression, anxiety, post-traumatic stress disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorder, schizophrenia and other psychosis syndromes, and personality disorders and personality traits and incident dementia. Here, we highlight findings indicating possible associations between these psychiatric disorders and subsequent dementia and suggest that some psychiatric disorders may be risk factors for incident dementia. Further research, including more large longitudinal studies and additional meta-analyses, however, is needed to better characterize the associations between psychiatric disorders and incident dementia, to identify possible mechanisms for these putative associations, and to identify risk factors within psychiatric disorders that predispose some people with a psychiatric disorder but not others to subsequent dementia. Additional important questions concern how the treatment of psychiatric disorders might affect the risk of incident dementia.

Lithium Exposure and Risk of Major Neurocognitive Disorders: A Systematic Review and Meta-analysis

BACKGROUND

Published studies on the association between lithium use and the decreased risk of major neurocognitive disorders (MNCDs) have shown disparities in their conclusions. We aimed to provide updated evidence of this association.

METHODS

A comprehensive literature search was performed in PubMed, EMBASE, and Cochrane Library from inception until August 31, 2023. All the observational studies evaluating the association between lithium use and MNCD risk were eligible for inclusion. Pooled odds ratios (ORs) and 95% prediction intervals were computed using random-effects models.

RESULTS

Eight studies with 377,060 subjects were included in the analysis. In the general population on the association between lithium use versus nonuse and dementia, the OR was 0.94 (95% confidence interval [CI] = 0.77-1.24). Further analysis also demonstrated that lithium use was not associated with an increased risk of Alzheimer's disease (OR = 0.69, 95% CI: 0.31-1.65). When the analysis was restricted to individuals with bipolar disorder to reduce the confounding by clinical indication, lithium exposure was also not associated with a decreased risk of MNCD (OR = 0.9, 95% CI = 0.71-1.15).

CONCLUSION

The results of this systematic review and meta-analysis do not support a significant association between lithium use and the risk of MNCD.

Lithium Therapy's Potential to Lower Dementia Risk and the Prevalence of Alzheimer's Disease: A Meta-Analysis

INTRODUCTION

Dementia is a neurodegenerative disease with insidious onset and progressive progression, of which the most common type is Alzheimer's disease (AD). Lithium, a trace element in the body, has neuroprotective properties. However, whether lithium can treat dementia or AD remains a highly controversial topic. Therefore, we conducted a meta-analysis.

METHODS

A systematic literature review was conducted on PubMed, Embase, and Web of Science. Comparison of the effects of lithium on AD or dementia in terms of use, duration, and dosage, and meta-analysis to test whether lithium therapy is beneficial in ameliorating the onset of dementia or AD. Sensitivity analyses were performed using a stepwise exclusion method. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of included studies. We determined the relative risk (RR) between patient groups using a random-effects model.

RESULTS

A total of seven studies were included. The forest plot results showed that taking lithium therapy reduced the risk of AD (RR 0.59, 95% confidence interval [CI]: 0.44-0.78) and is also protective in reducing the risk of dementia (RR 0.66, 95% CI: 0.56-0.77). The duration of lithium therapy was able to affect dementia incidence (RR 0.70, 95% CI: 0.55-0.88); however, it is unclear how this effect might manifest in AD. It is also uncertain how many prescriptions for lithium treatment lower the chance of dementia development.

CONCLUSION

The duration of treatment and the usage of lithium therapy seem to lower the risk of AD and postpone the onset of dementia.

Neuropsychiatric and cognitive features of major depressive disorder in aging, based on the data from the US National Alzheimer's Coordinating Center (NACC)

OBJECTIVE

The diagnosis of Major Depressive Disorder (MDD) is based on the DSM-V criteria and is established by a clinician. This allows quantifying depression based on clinical criteria. As such, MDD differs from other types of depressions that are measured by subjective scales. Here, we evaluated the MDD risk factor on other neuropsychiatric symptoms (NPS) as well as MDD association with cognitive performance in Alzheimer's disease (AD), Mild Cognitive Impairment (MCI) and Healthy Controls (HC).

METHODS

Data of 208 patients with AD, 291 patients with MCI and 647 HC were extracted from the National Alzheimer's Coordinating Center database. All participants included in this study were assessed by a physician for the MDD criteria, underwent an NPS evaluation using the NeuroPsychiatric Inventory, and a comprehensive cognitive assessment. Participants were classified as being with and without MDD. We performed logistic regression and MANCOVA models respectively with NPS and cognitive performance as variables of interest and MDD as fixed factors within each group. The MANCOVA was controlled for the effects of age, sex, and education.

RESULTS

MDD increased the risk for psychotic, affective and behavioral NPS in MCI, as well as affective and behavioral NPS in HC and AD. Also, MCI with MDD had lower performance on selective attention and mental flexibility.

CONCLUSIONS

MDD seems to increase the probability of a prevalence of NPS in all groups (HC, MCI and AD). Longitudinal data processing would help to understand the neuropsychiatric evolution of elderly subjects with MDD.

Lithium: An Old Drug for New Therapeutic Strategy for Alzheimer's Disease and Related Dementia

BACKGROUND

Although Alzheimer's disease (AD) is the most common form of dementia, the effective treatment of AD is not available currently. Multiple trials of drugs, which were developed based on the amyloid hypothesis of AD, have not been highly successful to improve cognitive and other symptoms in AD patients, suggesting that it is necessary to explore additional and alternative approaches for the disease-modifying treatment of AD. The diverse lines of evidence have revealed that lithium reduces amyloid and tau pathology, attenuates neuronal loss, enhances synaptic plasticity, and improves cognitive function. Clinical studies have shown that lithium reduces the risk of AD and deters the progress of mild cognitive impairment and early AD.

SUMMARY

Our recent study has revealed that lithium stabilizes disruptive calcium homeostasis, and subsequently, attenuates the downstream neuropathogenic processes of AD. Through these therapeutic actions, lithium produces therapeutic effects on AD with potential to modify the disease process. This review critically analyzed the preclinical and clinical studies for the therapeutic effects of lithium on AD. We suggest that disruptive calcium homeostasis is likely to be the early neuropathological mechanism of AD, and the stabilization of disruptive calcium homeostasis by lithium would be associated with its therapeutic effects on neuropathology and cognitive deficits in AD.

KEY MESSAGES

Lithium is likely to be efficacious for AD as a disease-modifying drug by acting on multiple neuropathological targets including disruptive calcium homeostasis.

Lithium Provides Broad Therapeutic Benefits in an Alzheimer's Disease Mouse Model

BACKGROUND

Alzheimer's disease (AD) is a chronic neurodegenerative disorder with a progressive loss of cognitive function. Currently, no effective treatment regimen is available. Lithium, a mood stabilizer for bipolar disorder, exerts broad neuroprotective and neurotrophic actions and improves cognitive function.

OBJECTIVE

The study investigated if lithium stabilizes Ca2+ signaling abnormalities in hippocampal neurons and subsequently normalize downstream effects on AD neuropathology and synaptic plasticity in young AD mice.

METHODS

Four-month-old 3xTg-AD mice were treated with a LiCl diet chow for 30 days. At the end of the lithium treatment, a combination of two-photon Ca2+ imaging, electrophysiology, and immunohistochemistry assays were used to assess the effects of the LiCl treatment on inositol trisphosphate receptor (IP3R)-dependent endoplasmic reticulum (ER) Ca2+ and voltage-gated Ca2+ channel (VGCC)-mediated Ca2+ signaling in CA1 neurons, neuronal nitric oxide synthase (nNOS) and hyperphosphorylated tau (p-tau) levels and synaptic plasticity in the hippocampus and overlying cortex from 3xTg-ADmice.

RESULTS

Thirty-day LiCl treatment reduced aberrant IP3R-dependent ER Ca2+ and VGCC-mediated Ca2+ signaling in CA1 pyramidal neurons from 3xTg-AD mice and restored neuronal nitric oxide synthase (nNOS) and hyperphosphorylated tau (p-tau) levels to control levels in the hippocampal subfields and overlying cortex. The LiCl treatment enhanced post-tetanic potentiation (PTP), a form of short-term plasticity in the hippocampus.

CONCLUSION

The study found that lithium exerts therapeutic effects across several AD-associated early neuronal signaling abnormalities including aberrant Ca2+ signaling, nNOS, and p-tau formation and enhances short-term synaptic plasticity. Lithium could serve as an effective treatment or co-therapeutic for AD.

The Present State of Lithium for the Prevention of Dementia Related to Alzheimer's Dementia in Clinical and Epidemiological Studies: A Critical Review

Despite the unavailability of essential anti-dementia drugs, lithium may inhibit glycogen synthase kinase-3 (GSK-3) and decrease beta-amyloid and hyper-phosphorylated tau. In this review, we hypothesized that trace to standard levels of lithium (i.e., corresponding to the therapeutic levels for bipolar disorder) may be effective for dementia prevention. Excluding three insufficient level studies, we obtained two and one excellent clinical studies on standard and trace lithium levels, respectively, all of which supported the effects of lithium for dementia prevention. In addition, we identified good clinical and epidemiological studies (four each) on standard lithium levels, of which six studies supported the effects of lithium. Moreover, of three good epidemiological studies on trace lithium levels, two supported the aforementioned effects of lithium. The number of studies were substantially small, particularly those on trace lithium levels. Moreover, studies on standard lithium levels were insufficient to establish the efficacy of lithium for dementia prevention. This necessitates accumulating good or excellent clinical evidence for the effects of trace to standard lithium levels on dementia prevention.

Atypical Antipsychotics Augmentation in Patients with Depressive Disorder and Risk of Subsequent Dementia: A Nationwide Population-Based Cohort Study

BACKGROUND

While atypical antipsychotic medications are widely used for treating depressive disorders, their long-term effects on the risk of subsequent dementia have not been studied adequately.

OBJECTIVE

To investigate whether the risk of dementia differs according to the use of atypical antipsychotic drugs, and compare the effects of antipsychotic agents on dementia risk in individuals with late-life depressive disorders.

METHODS

A nationwide population-based retrospective cohort study was conducted using data from the National Health Insurance Service-Senior Cohort of South Korea. Atypical antipsychotic dosages were standardized using a defined daily dose, and the cumulative dosage was calculated. Participants were observed from January 2008 to December 2015. Cox proportional hazard regression analysis was used to estimate the hazard ratios.

RESULTS

The cohort included 43,788 elderly adults with depressive disorders: 9,901 participants (22.6%) were diagnosed with dementia. Findings showed that atypical antipsychotics were prescribed to 1,967 participants (4.5%). Compared with non-users, users of atypical antipsychotics experienced a significantly higher risk for dementia with an adjusted hazard ratio (aHR) of 1.541 (95% confidence interval [CI], 1.415-1.678). A cumulative dose-response relationship was observed (test for trend, p < 0.0001). Among atypical antipsychotics, risperidone displayed the highest risk for dementia (aHR 1.767, [95% CI, 1.555-2.009]).

CONCLUSION

In this study of elderly individuals with depressive disorders, atypical antipsychotic use was associated with a significantly higher risk of subsequent dementia. Healthcare professionals should be aware of this potential long-term risk. A limitation that should be mentioned is that we could not exclude patients with bipolar depression.

Small molecule therapeutics for tauopathy in Alzheimer's disease: Walking on the path of most resistance

Alzheimer's disease (AD) is the most common form of dementia characterized by presence of extracellular amyloid plaques and intracellular neurofibrillary tangles composed of tau protein. Currently there are close to 50 million people living with dementia and this figure is expected to increase to 75 million by 2030 putting a huge burden on the economy due to the health care cost. Considering the effects on quality of life of patients and the increasing burden on the economy, there is an enormous need of new disease modifying therapies to tackle this disease. The current therapies are dominated by only symptomatic treatments including cholinesterase inhibitors and N-methyl-D-aspartate receptor blockers but no disease modifying treatments exist so far. After several failed attempts to develop drugs against amyloidopathy, tau targeting approaches have been in the main focus of drug development against AD. After an overview of the tauopathy in AD, this review summarizes recent findings on the development of small molecules as therapeutics targeting tau modification, aggregation, and degradation, and tau-oriented multi-target directed ligands. Overall, this work aims to provide a comprehensive and critical overview of small molecules which are being explored as a lead candidate for discovering drugs against tauopathy in AD.

Risk of dementia in bipolar disorder and the interplay of lithium: a systematic review and meta-analyses

OBJECTIVES

To assess whether bipolar disorder (BD) increases the rate of dementia and whether lithium is related to a lower risk of dementia in BD.

METHODS

A total of 10 studies (6859 BD; 487 966 controls) were included in the meta-analysis to test whether BD is a risk factor for dementia. In addition, five studies (6483 lithium; 43 496 non-lithium) were included in the meta-analysis about the potential protective effect of lithium in BD.

RESULTS

BD increases the risk of dementia (odds ratio (OR): 2.96 [95% CI: 2.09-4.18], P < 0.001), and treatment with lithium decreases the risk of dementia in BD (OR: 0.51 [95% CI: 0.36-0.72], P < 0.0001). In addition, secondary findings from our systematic review showed that the risk of progression to dementia is higher in BD than in major depressive disorder (MDD). Moreover, the number of mood episodes predicted the development of dementia in BD.

CONCLUSION

Individuals with BD are at higher risk of dementia than both the general population or those with MDD. Lithium appears to reduce the risk of developing dementia in BD.

Depression and Antidepressants as Potential Risk Factors in Dementia: A Systematic Review and Meta-analysis of 18 Longitudinal Studies

OBJECTIVE

To investigate whether depression and/or antidepressants can be a potential risk factor for the development of dementia and mild cognitive impairment (MCI).

DESIGN

Systematic review and meta-analysis of longitudinal studies.

SETTING AND PARTICIPANTS

Community or clinical settings. Participants included patients with depression, antidepressant users, and the general population.

MEASURES

Longitudinal studies evaluating the risks of dementia or MCI in patients with depression and/or antidepressant users were identified from the OVID database. The outcomes were the number of patients who developed dementia or MCI among the antidepressant users and nonusers. Relative risk (RR) with 95% confidence interval (95% CI) was used to evaluate the association between the use of antidepressants and the risk of dementia and MCI. Meta-analysis was used for combining the effect sizes of individual studies, and the heterogeneity test was performed. Risk of bias and reporting quality of included studies was assessed. Subgroup analyses were conducted for different types of antidepressants.

RESULTS

A total of 18 studies with 2,119,627 participants with mean age ranging from 55 to 81 years were included. Among patients with depression, antidepressant users showed a significantly higher risk of dementia (RR = 1.37, 95% CI = 1.11-1.70) and MCI (RR = 1.20, 95% CI = 1.02-1.42) than the nonusers. Besides, patients with depression who used antidepressants and who did not use antidepressants also showed significantly higher risk of dementia than the general population (RR = 1.50, 95% CI = 1.26-1.78, and RR = 1.31, 95% CI = 1.15-1.51, respectively).

CONCLUSIONS/IMPLICATIONS

Patients with depression are associated with a higher risk of dementia, and the use of antidepressants is not shown to be a protective factor of dementia. Further large-scale trials are required for investigation of the benefit-risk ratio between depression relapse and dementia when prescribing antidepressants.

Impact of Antidepressant Use on the Trajectory of Alzheimer's Disease: Evidence, Mechanisms, and Therapeutic Implications

The relationship between antidepressants and Alzheimer's disease (AD) is very complex, and the literature is mixed regarding the effect of these medications on the trajectory of the disease. This paper reviews findings from relevant clinical studies that have assessed the impact of antidepressants on AD onset and disease progression. To date, these medications seem to attenuate the risk of developing the disease without affecting the rate of progression. However, most evidence stems from observational studies that are subject to methodological bias. Serotonergic antidepressants are thought to affect AD pathophysiology by reducing β-amyloid (Aβ) plaque formation and promoting hippocampal neurogenesis. However, the mechanisms underlying their effect need to be examined further, especially in humans. Moreover, more robust clinical studies in terms of design (randomized controlled trials) and longer duration of follow-up are needed. Variables, including depression timeline/onset and its clinical course, apolipoprotein E4 (APOE4) genotype status, sex, dose/duration of antidepressant treatment, and AD biomarkers need to be incorporated in future trials to better elucidate the effect of antidepressants on AD risk.

The association of antidepressant drug usage with cognitive impairment or dementia, including Alzheimer disease: A systematic review and meta-analysis

OBJECTIVE

To determine if antidepressant drug usage is associated with cognitive impairment or dementia, including Alzheimer disease (AD).

METHOD

We conducted a systematic search of Medline, PubMed, PsycINFO, Web of Science, Embase, CINAHL, and the Cochrane Library. An initial screen by abstracts and titles was performed, and relevant full articles were then reviewed and assessed for their methodologic quality. Crude effect estimates were extracted from the included articles and a pooled estimate was obtained using a random effects model.

RESULTS

Five articles were selected from an initial pool of 4,123 articles. Use of antidepressant drugs was associated with a significant twofold increase in the odds of some form of cognitive impairment or dementia (OR = 2.17). Age was identified as a likely modifier of the association between antidepressant use and some form of cognitive impairment or AD/dementia. Studies that included participants with an average age equal to or greater than 65 years showed an increased odds of some form of cognitive impairment with antidepressant drug usage (OR = 1.65), whereas those with participants less than age 65 revealed an even stronger association (OR = 3.25).

CONCLUSIONS

Antidepressant drug usage is associated with AD/dementia and this is particularly evident if usage begins before age 65. This association may arise due to confounding by depression or depression severity. However, biological mechanisms potentially linking antidepressant exposure to dementia have been described, so an etiological effect of antidepressants is possible. With this confirmation that an association exists, clarification of underlying etiologic pathways requires urgent attention.

Patients receiving lithium therapy have a reduced prevalence of neurological and cardiovascular disorders

A variety of evidence from laboratory and animal studies suggests that lithium has neurotrophic and cytoprotective properties, and may ameliorate or prevent some disease states. We investigated whether such a protective effect can be observed in human psychiatric patients receiving lithium therapy. We carried out a retrospective chart review of 1028 adult psychiatric male and female outpatients attending four lithium clinics in metropolitan New York City. Patients were divided into two groups based on lithium usage, and the prevalence of neurological and cardiovascular disorders was compared. The main outcome measures were the occurrence in the two patient groups of a variety of neurological disorders and myocardial infarction. Odds ratios were calculated to assess the risk of having a disorder for patients receiving lithium compared to patients not receiving lithium: for seizures, the odds ratio was 0.097; for amyotrophic lateral sclerosis, the odds ratio was 0.112; for dementia not otherwise specified, the odds ratio was 0.112; and for myocardial infarction, the odds ratio was 0.30. Logistical regression analysis showed that lithium treatment is a significant negative predictive factor in the prevalence of each of these disease states, when age, duration of clinic attendance, and use of anti-psychotic medications are taken into account. Our results show that patients receiving regular lithium treatment have a reduced prevalence of some neurological disorders and myocardial infarctions. One possible explanation of these results is that a protective effect of lithium observed in laboratory and animal studies may also be present in human patients receiving regular lithium therapy.

Standard and trace-dose lithium: a systematic review of dementia prevention and other behavioral benefits

OBJECTIVE

Dementia is a major public health issue, with notably high rates in persons with mood illnesses. Lithium has been shown to have considerable neuroprotective effects, even in trace or low doses. The aim of this review is to summarize the current understanding of lithium benefits in trace or low doses in dementia prevention and for other behavioral or medical benefits.

METHODS

A systematic review identified 24 clinical, epidemiological, and biological reports that met inclusion criteria of assessing lithium in standard or low doses for dementia or other behavioral or medical benefits.

RESULTS

Five out of seven epidemiological studies found an association between standard-dose lithium and low dementia rates. Nine out of 11 epidemiological studies, usually of drinking water sources, found an association between trace-dose lithium and low suicide/homicide/mortality and crime rates. All four small randomized clinical trials of lithium for Alzheimer's dementia have found at least some clinical or biological benefits versus placebo. Only one small randomized clinical trial (RCT) of trace lithium has been conducted, assessing mood symptoms in former substance abusers, and found benefit with lithium versus placebo.

CONCLUSIONS

Lithium, in both standard and trace doses, appears to have biological benefits for dementia, suicide, and other behavioral outcomes. Further RCT research of trace lithium in dementia is warranted.

Bipolar disorders in DSM-5: strengths, problems and perspectives

The diagnostic classification of mood disorders by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) had two major shortcomings: an underdiagnosis of bipolar disorders and a large proportion of treated patients had to be allocated to the vague NOS groups ‘not otherwise specified’. Several new subthreshold groups of depression, bipolar disorders and mixed states are now operationally defined in DSM-5. In addition, hypomanic and manic episodes occurring during antidepressant treatments are, under certain conditions, accepted as criteria for bipolar disorders. The diagnosis of bipolarity now requires, as entry criterion A, not only the presence of elated or irritable mood but also the association of these symptoms with increased energy/activity. This restriction will unfortunately change the diagnoses of some patients from DSM-IV bipolar I and II disorders to subdiagnostic bipolar syndromes. Nonetheless, overall, DSM-5 is a step in the right direction, specifying more subdiagnostic categories with an improved dimensional approach to severity. DSM-5 may also have an impact on patient selection for placebo-controlled drug trials with antidepressants.

The neurotrophic and neuroprotective effects of psychotropic agents

Accumulating evidence suggests that psychotropic agents such as mood stabilizers, antidepressants, and antipsychotics realize their neurotrophic/neuroprotective effects by activating the mitogen activated protein kinaselextracellular signal-related kinase, PI3-kinase, and winglesslglycogen synthase kinase (GSK) 3 signaling pathways. These agents also upregulate the expression of trophic/protective molecules such as brain-derived neurotrophic factor, nerve growth factor, B-cell lymphoma 2, serine-threonine kinase, and Bcl-2 associated athanogene 1, and inactivate proapoptotic molecules such as GSK-3, They also promote neurogenesis and are protective in models of neurodegenerative diseases and ischemia. Most if not all, of this evidence was collected from animal studies that used clinically relevant treatment regimens. Furthermore, human imaging studies have found that these agents increase the volume and density of brain tissue, as well as levels of N-acetyl aspartate and glutamate in selected brain regions. Taken together, these data suggest that the neurotrophic/neuroprotective effects of these agents have broad therapeutic potential in the treatment, not only of mood disorders and schizophrenia, but also neurodegenerative diseases and ischemia.

The role of lithium in the treatment of bipolar disorder: convergent evidence for neurotrophic effects as a unifying hypothesis

Lithium has been and continues to be the mainstay of bipolar disorder (BD) pharmacotherapy for acute mood episodes, switch prevention, prophylactic treatment, and suicide prevention. Lithium is also the definitive proof-of-concept agent in BD, although it has recently been studied in other psychoses as well as diverse neurodegenerative disorders. Its neurotrophic effects can be viewed as a unifying model to explain several integrated aspects of the pathophysiology of mood disorders and putative therapeutics for those disorders. Enhancing neuroprotection (which directly involves neurotrophic effects) is a therapeutic strategy intended to slow or halt the progression of neuronal loss, thus producing long-term benefits by favorably influencing outcome and preventing either the onset of disease or clinical decline. The present article: (i) reviews what has been learned regarding lithium's neurotrophic effects since Cade's original studies with this compound; (ii) presents human data supporting the presence of cellular atrophy and death in BD as well as neurotrophic effects associated with lithium in human studies; (iii) describes key direct targets of lithium involved in these neurotrophic effects, including neurotrophins, glycogen synthase kinase 3 (GSK-3), and mitochondrial/endoplasmic reticulum key proteins; and (iv) discusses lithium's neurotrophic effects in models of apoptosis and excitotoxicity as well as its potential neurotrophic effects in models of neurological disorders. Taken together, the evidence reviewed here suggests that lithium's neurotrophic effects in BD are an example of an old molecule acting as a new proof-of-concept agent. Continued work to decipher lithium's molecular actions will likely lead to the development of not only improved therapeutics for BD, but to neurotrophic enhancers that could prove useful in the treatment of many other illnesses.

Bipolar disorder--methodological problems and future perspectives

Since its “rebirth” in 1966, bipolar disorder (BPD) has rapidly come to occupy a central position in the research and treatment of mood disorders. Compared with major depressive disorder (MDD), BPD is a more serious condition, characterized by much more frequent recurrence, more complex comorbidity, and higher mortality. One major problem is the lack of valid definitions in adult and in child psychiatry; the current definitions are unsatisfactory, and heavily favor an overdiagnosis of MDD. Biological research is partially based on those definitions, which have a short half-life. An additional, dimensional, approach, quantifying hypomania, depression, and anxiety by self-assessment and symptom checklists is recommended, A further, related problem is the early recognition of the onset of BPD, especially in adolescence, and the identification of correlates in childhood. Early and timely diagnosis of BPD is necessary to enable prompt intervention and secondary prevention of the disorder. The paper describes the current status and future directions of developing clinical concepts of bipolarity

Cellular plasticity cascades in the pathophysiology and treatment of bipolar disorder

Bipolar disorder (BPD) is characterized by recurrent episodes of disturbed affect including mania and depression as well as changes in psychovegetative function, cognitive performance, and general health. A growing body of data suggests that BPD arises from abnormalities in synaptic and neuronal plasticity cascades, leading to aberrant information processing in critical synapses and circuits. Thus, these illnesses can best be conceptualized as genetically influenced disorders of synapses and circuits rather than simply as deficits or excesses in individual neurotransmitters. In addition, commonly used mood-stabilizing drugs that are effective in treating BPD have been shown to target intracellular signaling pathways that control synaptic plasticity and cellular resilience. In this article we draw on clinical, preclinical, neuroimaging, and post-mortem data to discuss the neurobiology of BPD within a conceptual framework while highlighting the role of neuroplasticity in the pathophysiology and treatment of this disorder.