No abnormal hexanucleotide repeat expansion of C9ORF72 in Japanese schizophrenia patients

Psychosis in Neurodegenerative Dementias: A Systematic Comparative Review

Background

Psychosis, characterized by delusions and/or hallucinations, is frequently observed during the progression of Alzheimer's disease (AD) and other neurodegenerative dementias (ND) (i.e., dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD)) and cause diagnostic and management difficulties.

Objective

This review aims at presenting a concise and up-to-date overview of psychotic symptoms that occur in patients with ND with a comparative approach.

Methods

A systematic review was conducted following the PRISMA guidelines. 98 original studies investigating psychosis phenotypes in neurodegenerative dementias were identified (40 cohort studies, 57 case reports).

Results

Psychosis is a frequently observed phenomenon during the course of ND, with reported prevalence ranging from 22.5% to 54.1% in AD, 55.9% to 73.9% in DLB, and 18% to 42% in FTD. Throughout all stages of these diseases, noticeable patterns emerge depending on their underlying causes. Misidentification delusions (16.6-78.3%) and visual hallucinations (50-69.6%) are frequently observed in DLB, while paranoid ideas and somatic preoccupations seem to be particularly common in AD and FTD, (respectively 9.1-60.3% and 3.10-41.5%). Limited data were found regarding psychosis in the early stages of these disorders.

Conclusions

Literature data suggest that different ND are associated with noticeable variations in psychotic phenotypes, reflecting disease-specific tendencies. Further studies focusing on the early stages of these disorders are necessary to enhance our understanding of early psychotic manifestations associated with ND and help in differential diagnosis issues.

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.

Psychiatric disorders in C9orf72 kindreds

Objective

The aim of this study was to determine in a systematic manner if the C9orf72 phenotype might extend beyond frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) to include psychiatric disease.

Methods

A validated semistructured family history interview was conducted in a large cohort of patients with FTD and ALS (n = 89), with and without the C9orf72 expansion (n = 29 and n = 60, respectively), encompassing 1,414 first- and second-degree relatives. Statistical analyses used both the hazard ratio (HR) and the relative risk ratio to determine the risk profiles within families.

Results

A significant HR of 4.9 (95% confidence interval [CI]: 1.9–13.9, p = 0.003) confirmed a higher probability of developing schizophrenia for relatives of C9orf72 carriers compared with noncarriers. In addition, 8 relatives of C9orf72 carriers experienced an episode of late-onset psychosis unrelated to schizophrenia, in comparison to one noncarrier (HR = 17.9, 95% CI: 2.2–143.2, p = 0.007). The probability of suicide was also significantly higher for family members of C9orf72 carriers (HR = 2.7, 95% CI: 1.2–6.2, p = 0.02). An HR of 2.7 (95% CI: 1.1–6.9, p = 0.03) indicated a higher probability of autism spectrum disorder (ASD) in family members of C9orf72 carriers, and this risk extended to FTD. Furthermore, there was a positive association between psychosis in probands and mental health disorders, including ASD in their family members (p = 0.04).

Conclusion

Overall, the results from this study suggest that a psychiatric phenotype exists within C9orf72 kindreds. Further studies should attempt to delineate the risk of psychiatric disorders in C9orf72 kindreds to aid in clinical decision making, particularly regarding genetic counseling, through collaborations between neurology and psychiatry.

Psychotic symptoms in frontotemporal dementia

Although psychotic features have long been recognized in association with frontotemporal dementia (FTD), recent genetic discoveries enabling further subtyping of FTD have revealed that psychotic symptoms are frequent in some forms of FTD. Hallucinations and delusions can even precede onset of other cognitive or behavioural symptoms in patients with FTD. In this review, we explore the frequency and types of psychotic symptoms reported in patients with FTD, as well as in other neuropsychiatric disorders, to aid practitioners' consideration of these features in the diagnosis of FTD and related disorders.

Frontotemporal Dementia and Psychiatric Illness: Emerging Clinical and Biological Links in Gene Carriers

OBJECTIVE

To describe psychiatric presentations in individuals with genetic mutations causing frontotemporal dementia (FTD).

DESIGN

Case descriptions from five carriers of FTD-related gene mutations with symptoms associated with non-neurodegenerative psychiatric disease.

SETTING

A comprehensive research program investigating genetic and non-genetic FTD at the University of California, San Francisco Memory and Aging Center.

PARTICIPANTS

Three proband and two non-proband gene carriers.

MEASUREMENTS

Medical history and neurological examination, neuropsychological testing, magnetic resonance and/or positron emission tomography imaging, and a genetic analysis to screen for dementia-related mutations. Genetic status was unknown at the time of initial evaluation.

RESULTS

The chosen cases are illustrative of the variety of presentations of psychiatric symptoms in FTD gene carriers. In some cases, a non-neurodegenerative psychiatric illness was diagnosed based on specific symptoms, but the diagnosis may have been inappropriate based on the overall syndrome. In other cases, symptoms closely resembling those seen in non-neurodegenerative psychiatric illness did occur, in some cases immediately preceding the development of dementia, and in other cases developing a decade prior to dementia symptoms.

CONCLUSIONS

Psychiatric symptoms in FTD gene carriers can be very similar to those seen in non-neurodegenerative psychiatric illness. Psychiatric symptoms with atypical features (e.g., late-life onset, insidiously worsening course) should prompt careful assessment for neurodegenerative disease. Guidelines for such an assessment should be established.

C9orf72 repeat expansions that cause frontotemporal dementia are detectable among patients with psychosis

A pathologic hexanucleotide repeat expansion in C9orf72 causes frontotemporal dementia (FTD) or amyotrophic lateral sclerosis (ALS). Behavioral abnormalities can also occur among mutation carriers with FTD, but it is uncertain whether such mutations occur among persons with psychoses per se. Among participants in a genetic study of psychoses (N=739), two pairs of related individuals had C9orf72 expansions, of whom three were diagnosed with schizophrenia (SZ) / schizoaffective disorder (SZA), but their clinical features did not suggest dementia or ALS. A few patients with SZ/SZA carry C9orf72 repeat expansions; such individuals are highly likely to develop FTD/ALS.

Hexanucleotide Repeat Expansion in C9ORF72 Is Not Detected in the Treatment-Resistant Schizophrenia Patients of Chinese Han

Hexanucleotide (GGGGCC) repeat expansion in C9ORF72 (HRE) causes frontotemporal lobar degeneration, frontotemporal dementia–amyotrophic lateral sclerosis, and amyotrophic lateral sclerosis. HRE was also seen in the genomes of patients suffering from several other degenerative diseases. However, whether it is present in the treatment-resistant schizophrenia patients remains unknown. Genotyping 386 patients suffering from treatment-resistant schizophrenia using the method of Repeat-Primed PCR, we reported here that no HRE was detected in the patients of Chinese Han.