C9ORF72 repeat expansion and bipolar disorder - is there a link? No mutation detected in a Sardinian cohort of patients with bipolar disorder

C9orf72 Repeat Expansion Initially Presenting as Late-Onset Bipolar Disorder With Psychosis

INTRODUCTION

C9orf72 expansion is the most common genetic abnormality in behavioral variant frontotemporal dementia (bvFTD) and amyotrophic lateral sclerosis. Although psychiatric prodromes are common in C9orf72 expansion carriers, there are only scattered reported cases of primary psychiatric disorders, such as bipolar disorder, diagnosed at disease onset. Moreover, C9orf72 carrier status is rarely identified in bipolar disorder genetic studies.

CASE REPORT

A 51-year-old, right-handed woman with 16 years of education presented for evaluation of long-standing cognitive and behavioral change. She initially displayed symptoms of mania and florid, multimodal psychotic symptoms at age 39. Her bipolar disorder symptoms were initially responsive to medication; however, she later developed executive dysfunction and behavioral symptoms consistent with bvFTD. She became progressively nonverbal, and her limited speech was notable for speech apraxia. At the time of presentation, she demonstrated cortical sensory deficit, ideomotor and oral-buccal apraxia, and unstable gait. Neuroimaging revealed diffuse brain atrophy. Postmortem histopathological evaluation revealed frontotemporal lobar degeneration with TDP-43 inclusions, type B, and genetic study identified C9orf72 expansion. A detailed review of family history found a strong paternal history of bipolar disorder and substance use disorder.

CONCLUSIONS

We describe a rare case of C9orf72 expansion initially characterized by late-onset bipolar disorder and florid, multimodal psychotic symptoms, followed years later by bvFTD diagnosis. This report emphasizes the importance of completing a neurological examination, obtaining a detailed family history, and pursuing genetic screening to distinguish between primary psychiatric disorder and bvFTD in individuals who meet the criteria for late-onset bipolar disorder.

Bipolar Disorder and Manic-Like Symptoms in Alzheimer's, Vascular and Frontotemporal Dementia: A Systematic Review

BACKGROUND

An increased risk of manic episodes has been reported in patients with neurodegenerative disorders, but the clinical features of bipolar disorder (BD) in different subtypes of dementia have not been thoroughly investigated.

OBJECTIVES

The main aim of this study is to systematically review clinical and therapeutic evidence about manic syndromes in patients with Alzheimer's disease (AD), vascular dementia (VaD), and frontotemporal dementia (FTD). Since manic-mixed episodes have been associated to negative outcomes in patients with dementia and often require medical intervention, we also critically summarized selected studies with relevance for the treatment of mania in patients with cognitive decline.

METHODS

A systematic review of the literature was conducted according to PRISMA guidelines. PubMed, Scopus, and Web of Science databases were searched up to February 2022. Sixty-one articles on patients with AD, VaD, or FTD and BD or (hypo) mania have been included.

RESULTS

Manic symptoms seem to be associated to disease progression in AD, have a greatly variable temporal relationship with cognitive decline in VaD, and frequently coincide with or precede cognitive impairment in FTD. Overall, mood stabilizers, and electroconvulsive therapy may be the most effective treatments, while the benefits of short-term treatment with antipsychotic agents must be balanced with the associated risks. Importantly, low-dose lithium salts may exert neuroprotective activity in patients with AD.

CONCLUSION

Prevalence, course, and characteristics of manic syndromes in patients with dementia may be differentially affected by the nature of the underlying neurodegenerative conditions.

Frontotemporal Dementia and Late-Onset Bipolar Disorder: The Many Directions of a Busy Road

It is a common pathway for patients with the behavioral variant of frontotemporal dementia (bvFTD) to be first misdiagnosed with a primary psychiatric disorder, a considerable proportion of them being diagnosed with bipolar disorder (BD). Conversely, not rarely patients presenting in late life with a first episode of mania or atypically severe depression are initially considered to have dementia before the diagnosis of late-onset BD is reached. Beyond some shared features that make these conditions particularly prone to confusion, especially in the elderly, the relationship between bvFTD and BD is far from simple. Patients with BD often have cognitive complaints as part of their psychiatric disorder but are at an increased risk of developing dementia, including FTD. Likewise, apathy and disinhibition, common features of depression and mania, respectively, are among the core features of the bvFTD syndrome, not to mention that depression may coexist with dementia. In this article, we take advantage of the current knowledge on the neurobiology of these two nosologic entities to review their historical and conceptual interplay, highlighting the clinical, genetic and neuroimaging features that may be shared by both disorders or unique to each of them.

Recommendations to distinguish behavioural variant frontotemporal dementia from psychiatric disorders

The behavioural variant of frontotemporal dementia (bvFTD) is a frequent cause of early-onset dementia. The diagnosis of bvFTD remains challenging because of the limited accuracy of neuroimaging in the early disease stages and the absence of molecular biomarkers, and therefore relies predominantly on clinical assessment. BvFTD shows significant symptomatic overlap with non-degenerative primary psychiatric disorders including major depressive disorder, bipolar disorder, schizophrenia, obsessive-compulsive disorder, autism spectrum disorders and even personality disorders. To date, ∼50% of patients with bvFTD receive a prior psychiatric diagnosis, and average diagnostic delay is up to 5-6 years from symptom onset. It is also not uncommon for patients with primary psychiatric disorders to be wrongly diagnosed with bvFTD. The Neuropsychiatric International Consortium for Frontotemporal Dementia was recently established to determine the current best clinical practice and set up an international collaboration to share a common dataset for future research. The goal of the present paper was to review the existing literature on the diagnosis of bvFTD and its differential diagnosis with primary psychiatric disorders to provide consensus recommendations on the clinical assessment. A systematic literature search with a narrative review was performed to determine all bvFTD-related diagnostic evidence for the following topics: bvFTD history taking, psychiatric assessment, clinical scales, physical and neurological examination, bedside cognitive tests, neuropsychological assessment, social cognition, structural neuroimaging, functional neuroimaging, CSF and genetic testing. For each topic, responsible team members proposed a set of minimal requirements, optimal clinical recommendations, and tools requiring further research or those that should be developed. Recommendations were listed if they reached a ≥ 85% expert consensus based on an online survey among all consortium participants. New recommendations include performing at least one formal social cognition test in the standard neuropsychological battery for bvFTD. We emphasize the importance of 3D-T1 brain MRI with a standardized review protocol including validated visual atrophy rating scales, and to consider volumetric analyses if available. We clarify the role of 18F-fluorodeoxyglucose PET for the exclusion of bvFTD when normal, whereas non-specific regional metabolism abnormalities should not be over-interpreted in the case of a psychiatric differential diagnosis. We highlight the potential role of serum or CSF neurofilament light chain to differentiate bvFTD from primary psychiatric disorders. Finally, based on the increasing literature and clinical experience, the consortium determined that screening for C9orf72 mutation should be performed in all possible/probable bvFTD cases or suspected cases with strong psychiatric features.

Behavioral variant frontotemporal dementia in patients with previous severe mental illness: a systematic and critical review

ABSTRACT Objectives: To explore the relationship between severe/serious mental illness (SMI) and the behavioral variant of frontotemporal dementia (bvFTD), as the patterns of symptoms and cognitive performance that characterize both disorders share similarities. Methods: We performed a systematic review investigating what has already been published regarding the relationship between bvFTD and SMI. Studies were selected from PubMed and LILACS databases, including those published up to February 12, 2018. The search strategy included the following terms: “frontotemporal dementia” plus “bipolar”, OR “frontotemporal dementia” plus “schizophrenia”, OR “frontotemporal dementia” plus “schizoaffective”. Publications without abstracts, case reports with absent genetic or histopathological confirmation, reviews and non-English language papers were excluded across the search process. Results: The search on PubMed retrieved 186 articles, of which 42 met eligibility criteria. On the LILACS database, none met the requirements. Generally, three major research aims were identified: 1) to look for frontotemporal lobar degeneration-associated genetic abnormalities in patients with prior SMI; 2) to compare the cognitive profile between patients affected by neurodegenerative disorders and schizophrenic patients; 3) to highlight the association between bvFTD and preceding psychiatric conditions and/or distinguish them both. The investigated mutations were found infrequently in the studied SMI samples. Cross-sectional studies comparing cognitive performance between bvFTD and psychiatric disorders mostly found no remarkable differences. There were only a few case reports identifying definite frontotemporal lobar degeneration in patients with previous psychiatric diagnoses. Conclusions: The available evidence demonstrates how fragile the current understanding is regarding the association between bvFTD and prior SMI.

Update on the Epidemiology, Diagnosis, and Treatment of Mania in Older-Age Bipolar Disorder

PURPOSE OF REVIEW

The population over age 60 is growing more rapidly than the general population. Given the projected increase and need for data that can inform treatment, this review provides a brief description of newer publications focused on mania in older-age bipolar disorder (OABD), including epidemiology, diagnosis, and treatments.

RECENT FINDINGS

Age cutoffs to define OABD range from 50 to 65 years. OABD clinical presentation and course of illness is highly variable, often characterized by mood episode recurrence, medical comorbidity, cognitive deficits, and impaired functioning. There is little pharmacotherapy data on mania in OABD. Lithium and valproate have been tested in a single randomized controlled trial and there is data of more limited quality with other compounds. Treating OABD is challenging due to medical complexity, comorbidity, diminished tolerance to treatment, and a limited evidence base. More data is needed to keep pace with clinical demand.

Late life bipolar disorder evolving into frontotemporal dementia mimic

OBJECTIVES

Although bipolar disorder has been understood classically as a cyclic disease with full recovery between mood episodes, in the last decade, evidence has accumulated supporting progressive features. The clinical picture of advanced or end-stage bipolar disorder is heterogeneous with possible deficits in cognition and behavior, as illustrated by our case series.

CASES

From our neuropsychiatric outpatient clinic, we describe four cases with bipolar disorder gradually developing a clinical syndrome, including apathy, disinhibition, loss of empathy, stereotypical behavior, and compulsiveness, fulfilling the criteria for possible behavioral variant frontotemporal dementia. All cases were diagnosed with bipolar 1 disorder at least 10 years before the onset of the current symptoms, which were not due to recent mood episodes or switches of medication. In all cases, 3-7 years of follow-up yielded no progression. Repeated neuroimaging was within normal limits. Cerebrospinal fluid biomarker studies were not supportive of underlying neurodegenerative pathology. C9orf72 mutation status was negative in all cases.

CONCLUSION

Symptoms fitting the criteria for possible behavioral variant frontotemporal dementia may be present in end-stage of bipolar disorder. An alternative neurodegenerative nature seems unlikely based on repeated normal neuroimaging and the absence of clinical progression. Functional involvement of the frontal-subcortical networks might play a role.