Perseveration and Suicide in Huntington's Disease

Crym-positive striatal astrocytes gate perseverative behaviour

Astrocytes are heterogeneous glial cells of the central nervous system1-3. However, the physiological relevance of astrocyte diversity for neural circuits and behaviour remains unclear. Here we show that a specific population of astrocytes in the central striatum expresses μ-crystallin (encoded by Crym in mice and CRYM in humans) that is associated with several human diseases, including neuropsychiatric disorders4-7. In adult mice, reducing the levels of μ-crystallin in striatal astrocytes through CRISPR-Cas9-mediated knockout of Crym resulted in perseverative behaviours, increased fast synaptic excitation in medium spiny neurons and dysfunctional excitatory-inhibitory synaptic balance. Increased perseveration stemmed from the loss of astrocyte-gated control of neurotransmitter release from presynaptic terminals of orbitofrontal cortex-striatum projections. We found that perseveration could be remedied using presynaptic inhibitory chemogenetics8, and that this treatment also corrected the synaptic deficits. Together, our findings reveal converging molecular, synaptic, circuit and behavioural mechanisms by which a molecularly defined and allocated population of striatal astrocytes gates perseveration phenotypes that accompany neuropsychiatric disorders9-12. Our data show that Crym-positive striatal astrocytes have key biological functions within the central nervous system, and uncover astrocyte-neuron interaction mechanisms that could be targeted in treatments for perseveration.

Obsessive-compulsive and perseverative behaviors in Huntington's disease

Obsessive-compulsive and perseverative behaviors (OCBs/PBs) are characteristic features of Huntington's Disease (HD). Although a few recent research have attempted to discriminate between OCBs and PBs, most of the available evidence on OCBs does not consistently make this distinction. In this article, we aimed to explore the current inconsistencies in assessing and reporting OCBs/PBs and map the body of existing evidence. Up to half of the patients with motor manifest HD can experience OCBs. Separate reporting of PBs in HD patients has been uncommon among the studies and was frequently reported as a part of obsessive-compulsive symptoms. The structural limitation of the currently used rating scales and the overlaps in neuropathology and definition of OCBs and PBs are among the main reasons for the mixed reporting of OCBs/PBs. Perseverative thinking or behavior as a separate item is found in a few assessment tools, such as the Problem Behaviors Assessment - Short form (PBA-s). Even when the item exists, it is commonly reported as a composite score in combination with the obsessive-compulsive item. In addition to the significant psychological burden in individuals with HD, PBs are associated with somatic effects (e.g., cardiovascular symptoms) and high-risk behaviors (e.g., suicide). Recognition and monitoring of PBs in HD can aid in early detection of concerning symptoms and differentiating overlapping illnesses.

Do patients diagnosed with a neurological disease present increased risk of suicide?

INTRODUCTION

Neurological diseases are the leading cause of disability and the second leading cause of death worldwide. Physical and psychological pain, despair, and disconnection with the environment are observed after the diagnosis of numerous neurological processes, particularly neurodegenerative diseases.

DEVELOPMENT

A higher risk of suicide is observed in patients with such common neurological diseases as epilepsy, migraine, and multiple sclerosis, as well as in those with such degenerative disorders as Alzheimer disease, Huntington disease, amyotrophic lateral sclerosis, and Parkinson's disease. In most cases, suicidal ideation appears in the early stages after diagnosis, in the presence of disabling symptoms, and/or in patients with psychiatric comorbidities (often associated with these neurological diseases).

CONCLUSIONS

Effective suicide prevention in this population group requires assessment of the risk of suicide mainly in newly diagnosed patients, in patients showing unmistakable despair or disabling symptoms, and in patients presenting psychiatric comorbidities (especially depressive symptoms). It is essential to train specialists to detect warning signs in order that they may adopt a suitable approach and determine when psychiatric assessment is required.

Do patients diagnosed with a neurological disease present increased risk of suicide?

INTRODUCTION

Neurological diseases are the leading cause of disability and the second leading cause of death worldwide. Physical and psychological pain, despair, and disconnection with the environment are observed after the diagnosis of numerous neurological processes, particularly neurodegenerative diseases.

DEVELOPMENT

A higher risk of suicide is observed in patients with such common neurological diseases as epilepsy, migraine, and multiple sclerosis, as well as in those with such degenerative disorders as Alzheimer disease, Huntington disease, amyotrophic lateral sclerosis, and Parkinson's disease. In most cases, suicidal ideation appears in the early stages after diagnosis, in the presence of disabling symptoms, and/or in patients with psychiatric comorbidities (often associated with these neurological diseases).

CONCLUSIONS

Effective suicide prevention in this population group requires assessment of the risk of suicide mainly in newly diagnosed patients, in patients showing unmistakable despair or disabling symptoms, and in patients presenting psychiatric comorbidities (especially depressive symptoms). It is essential to train specialists to detect warning signs in order that they may adopt a suitable approach and determine when psychiatric assessment is required.

Obsessive-Compulsive and Perseverative Behaviors in Huntington's Disease

Background:

Neuropsychiatric symptoms are highly prevalent in Huntington’s disease (HD). However, little is known of the prevalence and course of obsessive-compulsive behaviors (OCBs) and perseverative behaviors (PBs) during the progression of the disease.

Objective:

This review provides a summary of the literature on OCBs and PBs in HD gene expansion carriers (HDGECs).

Methods:

Pubmed database was searched for articles on OCBs and PBs in HD up to 2017. We used search terms, all synonyms for HD, and various terms for OCBs and PBs.

Results:

We found 5 case series and 11 original articles that describe a prevalence range of 5 to 52% for OCBs and up to 75% for PBs depending on disease stage and measurement scale used. Premanifest HDGECs report more OCBs compared to controls, and manifest HDGECs report a higher rate of OCBs compared to premanifest HDGECs. OCBs and PBs are associated with a longer disease duration and disease severity in manifest HDGECs, but decrease in the most advanced stages. When HDGECs come closer to estimated motor onset, the companion ratings on OCBs appear to be higher than the self-ratings of HDGECs.

Conclusions:

Both OCBs and PBs are characteristic neuropsychiatric features of HD. Perseveration is probably best distinguished from OCBs as it occurs without the individual’s full awareness or insight into their presence (and the behavior may not be distressing). Although these behaviors are seldom distinguished, we conclude that differentiating OCBs from PBs in HD is beneficial for the management and treatment of these symptoms in HDGECs.

Adult-onset Huntington disease: An update

Appropriate nursing-care strategies depend on the early recognition of Huntington disease (HD) to prioritize a plan of care. This article offers perspective on the clinical presentation, prognosis, diagnosis, and management of adult-onset HD.

Risk factors for suicidality in Huntington disease: An analysis of the 2CARE clinical trial

OBJECTIVE

Most suicidality literature in Huntington disease (HD) is based on natural history studies or retrospective reviews, but reports on risk factors from clinical trials are limited.

METHODS

We analyzed 609 participants from 2CARE, a randomized, double-blind, placebo-controlled clinical trial with up to 5 years of follow-up, for risk factors related to suicidality. The primary outcome variable was the time from randomization until the first occurrence of either suicidal ideation or attempt. We also considered time from randomization until the first suicide attempt as a secondary outcome variable.

RESULTS

Depression, anxiety, bipolar disorder, antidepressant or anxiolytic use, and prior suicide attempt at baseline were associated with time to ideation or attempt. Baseline employment status, marital status, CAG repeat length, tetrabenazine use, and treatment assignment (coenzyme Q₁₀ or placebo) were not associated with suicidality. Time-dependent variables from the Unified Huntington's Disease Rating Scale Behavioral Assessment were associated with time to suicidal ideation or attempt, driven mainly by items related to depressed mood, low self-esteem/guilt, anxiety, suicidal thoughts, irritability, and compulsions. Variables associated with time to suicide attempt alone were generally similar.

CONCLUSION

These data suggest psychiatric comorbidities in HD are predictive of suicidal behavior while participating in clinical trials, reinforcing the importance of clinical surveillance and treatment towards lessening risk during participation and perhaps beyond. Designing a composite algorithm for early prediction of suicide attempts in HD may be of value, particularly given anticipated trials aimed at disease modification are likely to be long-term.

CLINICALTRIALSGOV IDENTIFIER

NCT00608881.