Disease stage, but not sex, predicts depression and psychological distress in Huntington's disease: A European population study

Association between sex and Huntington's disease: an updated review on symptomatology and prognosis of neurodegenerative disorders

Huntington's disease is a rare autosomal dominant disorder presenting with chorea, rigidity, hypo-/akinesia, cognitive decline, and psychiatric disturbances. Numerous risk factors have been defined in the onset of this disease. However, the number of CAG repeats in the genes are the most crucial factor rendering patients susceptible to the disease. Studies have shown significant differences in onset and disease presentation among the sexes, which prompts analysis of the impact of different sexes on disease etiology and progression. This article therefore discusses the evidence-based role of sex in aspects of symptomatology, pathogenesis, biomarkers, progression, and prognosis of Huntington's disease, with a secondary review of sex-linked differences in Alzheimer's and Parkinson's disease.

Gene-dosage- and sex-dependent differences in the prodromal-Like phase of the F344tgHD rat model for Huntington disease

In Huntington disease (HD) the prodromal phase has been increasingly investigated and is currently in focus for early interventional treatments. Also, the influence of sex on disease progression and severity in patients is under discussion, as a sex-specific impact has been reported in transgenic rodent models for HD. To this end, we have been studying these aspects in Sprague Dawley rats transgenic for HD. Here, we took up on the congenic F344tgHD rat model, expressing a fragmented Htt construct with 51 CAG repeats on an inbred F344 rat background and characterized potential sexual dimorphism and gene-dosage effects in rats during the pre-symptomatic phase (1-8 months of age). Our study comprises a longitudinal phenotyping of motor function, emotion and sensorimotor gating, as well as screening of metabolic parameters with classical and automated assays in combination with investigation of molecular HD hallmarks (striatal cell number and volume estimation, appearance of HTT aggregates). Differences between sexes became apparent during middle age, particularly in the motor and sensorimotor domains. Female individuals were generally more active, demonstrated different gait characteristics than males and less anxiolytic-like behavior. Alterations in both the time course and affected behavioral domains varied between male and female F344tgHD rats. First subtle behavioral anomalies were detected in transgenic F344tgHD rats prior to striatal MSN cell loss, revealing a prodromal-like phase in this model. Our findings demonstrate that the congenic F344tgHD rat model shows high face-validity, closely resembling the human disease's temporal progression, while having a relatively low number of CAG repeats, a slowly progressing pathology with a prodromal-like phase and a comparatively subtle phenotype. By differentiating the sexes regarding HD-related changes and characterizing the prodromal-like phase in this model, these findings provide a foundation for future treatment studies.

Sex differences in sleep architecture in a mouse model of Huntington's disease

Sleep and circadian rhythm disturbances are common features of Huntington's disease (HD). HD is an autosomal dominant neurodegenerative disorder that affects men and women in equal numbers, but some epidemiological studies as well as preclinical work indicate there may be sex differences in disease presentation and progression. Since sex differences in HD could provide important insights to understand cellular and molecular mechanism(s), we used the bacterial artificial chromosome transgenic mouse model of HD (BACHD) to examine whether sex differences in sleep/wake cycles are detectable in an animal model of the disease. Electroencephalography/electromyography (EEG/EMG) was used to measure sleep/wake states and polysomnographic patterns in young adult (12-week-old) male and female wild-type and BACHD mice. Our findings show that male, but not female, BACHD mice exhibited increased variation in phases of the rhythms as compared to age- and sex-matched wild-types. For both rapid-eye movement (REM) and non-rapid eye movement (NREM) sleep, genotypic and sex differences were detected. In particular, the BACHD males spent less time in NREM sleep and exhibited a more fragmented sleep than the other groups. Finally, in response to 6 h of sleep deprivation, both genotypes and sexes displayed the predicted homeostatic responses to sleep loss. These findings suggest that females are relatively protected early in disease progression in this HD model.

Sexual Dimorphism in Neurodegenerative Diseases and in Brain Ischemia

Epidemiological studies and clinical observations show evidence of sexual dimorphism in brain responses to several neurological conditions. It is suggested that sex-related differences between men and women may have profound effects on disease susceptibility, pathophysiology, and progression. Sexual differences of the brain are achieved through the complex interplay of several factors contributing to this phenomenon, such as sex hormones, as well as genetic and epigenetic differences. Despite recent advances, the precise link between these factors and brain disorders is incompletely understood. This review aims to briefly outline the most relevant aspects that differ between men and women in ischemia and neurodegenerative disorders (AD, PD, HD, ALS, and SM). Recognition of disparities between both sexes could aid the development of individual approaches to ameliorate or slow the progression of intractable disorders.

Sex and gender differences in movement disorders: Parkinson's disease, essential tremor, dystonia and chorea

Sex and gender-based differences in epidemiology, clinical features and therapeutical responses are emerging in several movement disorders, even though they are still not widely recognized. In this chapter, we summarize the most relevant evidence concerning these differences in Parkinson's disease, essential tremor, dystonia and chorea. Indeed, both sex-related biological (hormonal levels fluctuations) and gender-related variables (socio-cultural and environmental factors) may differently impact symptoms manifestation and severity, phenotype and disease progression of movement disorders on men and women. Moreover, sex differences in treatment responses should be taken into account in any therapeutical planning. Physicians need to be aware of these major differences between men and women that will eventually have a major impact on better tailoring prevention, treatment, or even delaying progression of the most common movement disorders.

The Lived Experiences of Depression in Huntington's Disease: A Qualitative Study

BACKGROUND

Depression is a common neuropsychiatric syndrome in Huntington's disease (HD) and has debilitating consequences, including poorer sleep, exacerbation of cognitive and functional decline, and suicidality. To date, no published studies have documented the lived experience of depression in HD, despite clinical evidence that depression may be experienced differently in HD compared to the general population.

OBJECTIVE

The aim of this study was to investigate the lived experiences of depression in people with the CAG expansion for HD using qualitative methods.

METHODS

We conducted semi-structured interviews with HD CAG expansion carriers who had current or previous experiences of depression, until data saturation was achieved. This resulted in interviews from 17 HD CAG expansion carriers (11 premanifest, 6 manifest) which were analyzed using thematic analysis.

RESULTS

The four key themes that emerged related to the temporal characteristics of depression in HD, the qualitative changes associated with depression, psychosocial stressors perceived to contribute to depression, and the perception of depression as an endogenous feature of HD.

CONCLUSION

This study provides an enriched understanding of the unique characteristics of depression in HD, and the attributions that CAG expansion carriers make for their depression symptoms. The themes identified in this study can be used to guide more targeted assessment and treatment of depression in HD.

Clinical Correlates of Depression and Suicidality in Huntington Disease: An Analysis of the Enroll-HD Observational Study

BACKGROUND

Depression and suicidality are commonly experienced by Huntington disease (HD) gene carriers. Research on these behavioral symptoms is imperative, not only to increase our understanding of the symptoms and how they relate to HD, but also to contribute to improving patients' care and quality of life.

OBJECTIVE

To identify clinical variables associated with a history of depression and suicidality in HD gene carriers.

METHOD

We conducted a cross-sectional study of HD gene carriers from the Enroll-HD database PDS4 (periodic data set 4; N = 11,582). Data from baseline visits were obtained, and binary logistic regression models were used to ascertain the effects of clinical variables on the likelihood that HD gene carriers would have previous depression and suicidal ideation/attempts.

RESULTS

Approximately 65% (n = 7526) of the HD gene carriers had a history of depression, and ~27% (n = 3152) had previous suicidal ideation/attempts. Female sex; diagnosis of manifest HD; history of perseverative/obsessive behavior, apathy, and psychosis; and previous suicidal ideation/attempts were significantly associated with a history of depression in the HD gene carriers. Medical history of apathy, psychosis, and depression, as well as worse scores on the Total Functional Capacity and Irritability Scales, were significantly associated with previous suicidal ideation/attempts in the HD gene carriers.

CONCLUSION

The prevalence of depression and suicidality is high among HD gene carriers. An improved understanding of the risk factors for depression and suicide in HD gene carriers can assist providers in recognizing at-risk individuals and allow providers to implement therapeutic strategies.

Sex Differences in Huntington's Disease: Evaluating the Enroll-HD Database

BACKGROUND

Identifying sex-related differences is critical for enhancing our understanding of factors that may impact prognosis and advance treatments in Huntington's disease (HD).

OBJECTIVES

To investigate if sex-related differences exist in clinical HD.

METHODS

Longitudinal study of the Enroll-HD database. Manifest HD patients were included in the analysis (N = 8401). Linear mixed models were used to assess motor, behavioral, and cognitive functioning over a series of four annual visits, and compared male and female HD gene carriers.

RESULTS

HD patients showed significant sex-dependent differences in motor, cognitive, and behavioral symptoms. Both sexes had worsened motor symptoms over the course of four visits, but there was a significant disparity between sexes, with females consistently presenting with more symptoms than males. For behavioral symptoms, specifically depressive symptoms, females had significantly more depressive symptoms, although self-reported symptoms in both sexes became less severe throughout time.

CONCLUSIONS

Our analyses suggest that women have worse symptoms than men during the course of HD.

Homozygosity of BACHD rats not only causes strong behavioral deficits in young female rats but also a reduced breeding success

Huntington's disease is known to be a purely genetic disease based on an expansion of a CAG base triplet repeat in the coding region of the Huntingtin gene. Some years ago, researchers were able to introduce the extensive full-length gene sequence of the mutant huntingtin gene into a rodent model. The resulting BACHD rat is already well characterized for behavioral deficits. So far, all analyses in this preclinical rat model were performed in male hemizygous animals. As homozygosity of transgenic models often causes an amplification of the phenotype and female HD patients present a stronger phenotype compared to men, we established a homozygous breeding colony and tested 2 and 5 months old homozygous male and female BACHD rats in a behavioral test battery. The tests included the grip strength test, Rota Rod, elevated plus maze, passive avoidance, and Barnes maze test. Our results show strong deficits in young female homozygous BACHD rats including increased body weight, motor deficits, muscle weakness, reduced anxiety and hypoactivity, as well as learning and memory deficits. Analysis of male homozygous BACHD rats showed only weak disease symptoms, similar compared to male hemizygous BACHD rats of already published studies. Evaluation of the breeding success showed that homozygous BACHD have a reduced number of pups at the time of birth that even decreases until weaning. Our results suggest that the phenotype of homozygous male BACHD rats barely differs from already published results of hemizygous BACHD rats while female homozygous BACHD rats display strong and early alterations.

Sex differences in movement disorders

A number of studies reported the possible differences between men and women in movement disorders. Evidence shows that estrogens may have a neuroprotective effect and may modulate the neurodevelopment of the different brain structures. Movement disorders including Parkinson's disease, dementia with Lewy body, Huntington's disease, Tourette's syndrome, and dystonia among others display significant clinical differences between sexes, with structural differences in the dopaminergic pathways between men and women. Here we summarize the most relevant clinical aspects of some of the most common movement disorders, highlighting the differences in disease onset, clinical presentation, therapy, and outcomes. Increased recognition of these differences may help physicians better understand the pathophysiology of these conditions and provide a tailored therapeutic approach.

Validation of Neuro-QoL and PROMIS Mental Health Patient Reported Outcome Measures in Persons with Huntington Disease

BACKGROUND

Patient-reported outcomes (PROs) for mental health are important for persons with Huntington disease (HD) who commonly experience symptoms of depression, anxiety, irritability, anger, aggression, and apathy. Given this, there is a need for reliable and valid patient-reported outcomes measures of mental health for use as patient-centered outcomes in clinical trials.

OBJECTIVE

Thus, the purpose of this study was to establish the psychometric properties (i.e., reliability and validity) of six Neuro-QoL and PROMIS mental health measures to support their clinical utility in persons with HD.

METHODS

294 individuals with premanifest (n = 102) or manifest HD (n = 131 early HD; n = 61 late HD) completed Neuro-QoL/PROMIS measures of Emotional and Behavioral Dyscontrol, Positive Affect and Well-Being, Stigma, Anger, Anxiety, and Depression, legacy measures of self-reported mental health, and clinician-rated assessments of functioning.

RESULTS

Convergent validity and discriminant validity for the Neuro-QoL and PROMIS measures of Emotional and Behavioral Dyscontrol, Positive Affect and Well-Being, Stigma, Anger, Anxiety, and Depression, were supported in persons with HD. Neuro-QoL measures of Anxiety and Depression also demonstrated moderate sensitivity and specificity (i.e., they were able to distinguish between individuals with and without clinically significant anxiety and depression).

CONCLUSIONS

Findings provide psychometric support for the clinical utility of the Neuro-QoL/PROMIS measures of mental health measures in persons with HD. As such, these measures should be considered for the standardized assessment of health-related quality of life in persons with HD.

The effects of multidisciplinary rehabilitation on neuroimaging, biological, cognitive and motor outcomes in individuals with premanifest Huntington's disease

BACKGROUND

Huntington's disease (HD) is a chronic, progressive neurodegenerative condition for which there are currently no proven disease-modifying therapies. Lifestyle factors have been shown to impact on the age of disease onset and progression of disease features. We therefore investigated the effects of a nine-month multidisciplinary rehabilitation intervention on neuroimaging, biological and clinical disease outcomes in individuals with premanifest HD.

METHODS

31 individuals with premanifest HD participated in the study. Eighteen participants underwent a nine-month multidisciplinary rehabilitation intervention comprising aerobic and resistance exercise, computerised cognitive training, dual-task training and sleep hygiene and nutritional guidance. The remaining 13 participants were allocated to a standard care control group. Neuroimaging, biological, cognitive, motor and cardiorespiratory fitness data was collected.

RESULTS

Participants displayed good adherence (87%) and compliance (85%) to the intervention. Maintenance of the shape of the right putamen was observed in the intervention group when compared to the control group. The intervention group displayed significant improvements in verbal learning and memory, attention, cognitive flexibility and processing speed following the intervention when compared to the control group. Performance on the mini-social cognition and emotional assessment (mini-SEA) was maintained in the intervention group, but decreased in the control group. No changes were observed in serum neurofilament light protein levels, postural stability outcomes or cardiorespiratory fitness.

CONCLUSION

This study adds to the accumulating body of literature to suggest that multidisciplinary rehabilitation is of clinical benefit for individuals with HD. Large randomised controlled trials are necessary to determine the extent to which benefits occur across the spectrum of the disease.

Why Woody got the blues: The neurobiology of depression in Huntington's disease

Huntington's disease (HD) is an extraordinary disorder that usually strikes when individuals are in the prime of their lives, as was the case for the influential 20th century musician Woody Guthrie. HD demonstrates the exceptionally fine line between life and death in such 'genetic diseases', as the only difference between those who suffer horribly and die slowly of this disease is often just a handful of extra tandem repeats (beyond the normal polymorphic range) in a genome that constitutes over 3 billion paired nucleotides of DNA. Furthermore, HD presents as a complex and heterogenous combination of psychiatric, cognitive and motor symptoms, so can appear as an unholy trinity of 'three disorders in one'. The autosomal dominant nature of the disorder is also extremely challenging for affected families, as a 'flip of a coin' dictates which children inherit the mutation from their affected parent, and the gene-negative family members bear the burden of caring for the other half of the family that is affected. In this review, we will focus on one of the earliest, and most devastating, symptoms associated with HD, depression, which has been reported to affect approximately half of gene-positive HD family members. We will discuss the pathogenesis of HD, and depressive symptoms in particular, including molecular and cellular mechanisms, and potential genetic and environmental modifiers. This expanding understanding of HD pathogenesis may not only lead to novel therapeutic options for HD families, but may also provide insights into depression in the wider population, which has the greatest burden of disease of any disorder and an enormous unmet need for new therapies.

Stress and neurodegeneration

Neurodegenerative diseases are a great concern because of aging worldwide population. Despite substantial effort to advance our understanding of the etiology and potential treatment of neurodegeneration, there remains a paucity of information with respect to this complex disease process. Interestingly, stress has been implicated among the potential mechanisms implicated in neurodegenerative pathology. Given the increase in chronic stress in modern society, this premise warrants further investigation. The aim of this review is to evaluate the influence of stress on neurodegeneration, the effect of neurodegenerative diseases diagnosis on stress, and therapeutic strategies for neurodegenerative diseases with a special focus on stress reduction. Neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's Disease showed an acceleration in disease progression and a worsening of symptoms under stress. Some therapies (e.g., yoga, meditation) focused on reducing stress showed beneficial effects against neurodegeneration. Nevertheless, more studies are necessary in order to completely understand the implications of stress in neurodegeneration and the usefulness of stress reduction in the treatment thereof.

Sex differences in movement disorders

In a range of neurological conditions, including movement disorders, sex-related differences are emerging not only in brain anatomy and function, but also in pathogenesis, clinical features and response to treatment. In Parkinson disease (PD), for example, oestrogens can influence the severity of motor symptoms, whereas elevation of androgens can exacerbate tic disorders. Nevertheless, the real impact of sex differences in movement disorders remains under-recognized. In this article, we provide an up-to-date review of sex-related differences in PD and the most common hyperkinetic movement disorders, namely, essential tremor, dystonia, Huntington disease and other chorea syndromes, and Tourette syndrome and other chronic tic disorders. We highlight the most relevant clinical aspects of movement disorders that differ between men and women. Increased recognition of these differences and their impact on patient care could aid the development of tailored approaches to the management of movement disorders and enable the optimization of preclinical research and clinical studies.

Monoaminergic System Modulation in Depression and Alzheimer's Disease: A New Standpoint?

The prevalence of depression has dramatically increased, and it has been estimated that over 300 million people suffer from depression all over the world. Depression is highly comorbid with many central and peripheral disorders. In this regard, depressive states have been associated with the development of neurological disorders such as Alzheimer's disease (AD). Accordingly, depression is a risk factor for AD and depressive symptomatology is common in pre-clinical AD, representing an early manifestation of this disease. Neuropsychiatric symptoms may represent prodromal symptoms of dementia deriving from neurobiological changes in specific cerebral regions; thus, the search for common biological substrates is becoming an imperative and intriguing field of research. Soluble forms of beta amyloid peptide (Aβ) have been implicated both in the development of early memory deficits and neuropsychiatric symptoms. Indeed, soluble Aβ species have been shown to induce a depressive-like phenotype in AD animal models. Alterations in monoamine content are a common feature of these neuropathologies. Interestingly, serotonergic system modulation has been implicated in alteration of Aβ production. In addition, noradrenaline is considered crucially involved in compensatory mechanisms, leading to increased Aβ degradation via several mechanisms, including microglia modulation. In further agreement, antidepressant drugs have also been shown to potentially modulate cognitive symptoms in AD and depression. Thus, the present review summarizes the main knowledge about biological and pathological substrates, such as monoamine and related molecules, commonly involved in AD and depression pathology, thus shading light on new therapeutic approaches.

Psychopathological dimensions in subjects with hereditary ATTR V30M amyloidosis and their relation with life events due to the disease

BACKGROUND

Chronic physical illness has been associated with emotional distress. Chronic diseases may change usual family patterns with economic, social and family losses. Hereditary ATTR V30M amyloidosis is a rare, fatal inherited systemic amyloidosis, with chronic evolution and beginning in adulthood.

AIMS AND METHODS

To evaluate psychopathological dimensions and how they correlated with disease-related life events, 209 symptomatic and asymptomatic carriers, participated in the study. Sociodemographic and Family and Personal History Disease questionnaires and brief symptom inventory (BSI) were applied.

RESULTS

BSI indices, global severity index (GSI), positive symptom index (PSI) and positive symptom total (PST) scored higher than general population. Independent predictors for GSI >0.83 were female sex (OR = 3.46, p = .005) and being symptomatic carriers (OR = 3.03, p = .039). Independent predictors of a PST >26.99 were female sex (OR = 3.74, p = .012) symptomatic carrier (OR = 5.32, p = .025), age between 15 and 24 years at affected parent's death (OR = 5.26, p = .04). Independent predictors of a PSI >1.56 were being asymptomatic carrier (OR = 6.3, p = .036); to have children (OR = 3.19, p = .043) and have ≤14 years at parent's disease onset (OR = 6.39, p = .05).

CONCLUSIONS

Results point to an important vulnerability of this population for psychological distress and psychiatric disease. Early life events related to disease, being sick and sex are associated with psychopathological distress.

Age at Death and Causes of Death in Patients with Huntington Disease in Norway in 1986-2015

BACKGROUND

The literature offers discrepant findings regarding age at death in individuals with Huntington disease (HD).

OBJECTIVE

To study the age at death and causes of death in males and females with a diagnosis of HD in Norway.

METHODS

Registry study of deaths in 1986-2015 using data from two national registries: the Norwegian Cause of Death Registry (NCDR) and the registry of the Centre for Rare Disorders (CRD), Oslo University Hospital.

RESULTS

Mean age at death for individuals with HD was found to be 63.9 years (NCDR) and 61.7 years (CRD), compared to a mean of 76.9 years in the general population (NCDR). There were no significant gender differences for age at death in individuals with HD. The significant increase in age at death within the general population from 1986 to 2015 was not observed in individuals with HD. In 73.5% of individuals with HD, the underlying cause of death was HD, followed by cardiovascular diseases, cancer and respiratory diseases. The most common immediate cause of death was respiratory diseases (44.2%). Suicide was a more common cause of death in the population with HD (2.3%) compared to the general population (1.3%).

CONCLUSION

The age at death of individuals with HD was stable over a period of 30 years and 13.3 years lower than in the general population. Longer life expectancy for females from the general population was not found in females with HD. Suicide was more common among individuals with HD compared to the general population.

Psychopathological Dimensions in Portuguese Subjects with Transthyretin Familial Amyloid Polyneuropathy

Background

Transthyretin familial amyloid polyneuropathy (TTR-FAP) is a fatal, chronic, progressive disease. It is a rare hereditary amyloidosis, which manifests as a sensorimotor neuropathy and autonomic dysfunction. It begins during adulthood.

Aims and Methods

Our aim is to evaluate psychopathological dimensions in a population attending a consultation center for TTR-FAP. Two hundred and nine subjects (symptomatic and asymptomatic carriers), 84 men and 127, women participated in the study. Most subjects were married (67.1%) and most of them were still working; 33% were retired from work or on a sick leave. A sociodemographic questionnaire and The Brief Symptom Inventory (BSI) were applied. Statistical analysis was performed (descriptive analysis, Mann-Whitney, Wilcoxon, and Spearman tests).

Results

The Global Symptom Index (GSI) was significantly higher in patients (p = 0.001). Considering GSI, 32.7% of total subjects were above the median for general population. When subgroups were evaluated, 25.6% of symptomatic carriers, 26.3% of subjects without established diagnosis, and 39.1% of patients were above median. GSI was significantly higher in patients (p = 0.001). Some BSI dimensions were also significantly higher in the patient group (somatization, depression, anxiety, and psychoticism) when compared with carriers. Women scored higher than men. Sick women scored higher for all dimensions except somatization. Asymptomatic carriers scored statistically higher for phobic anxiety (p = 0.01), interpersonal sensitivity, anxiety, and depression. In patients, most dimensions and GSI (rho = 0.33, p = 0.002) had positive correlations with years of disease.

Conclusions

TTR-FAP patients and carriers are a very vulnerable group for psychological distress and psychopathological problems. Women and patients are at higher risk.

Psychiatric comorbidities in movement disorders

Psychiatric comorbidities are common in movement disorders. This review provides a practical approach to help clinicians to recognize psychiatric disorders in the most frequent movement disorders. However, the extent of neurodegeneration, as well as the impact of medications with considerable CNS effects, influences the diverse psychiatric presentations that, in turn, are influenced by the stress of living with a movement disorder. Depression, anxiety, and psychosis are the most common psychiatric comorbidities in movement disorders and of the medications used to treat the motor disturbances. These psychiatric problems impair patients' functioning throughout the course of the chronic neurodegenerative diseases. Due to the direct connection between brain dysfunction and psychiatric symptoms, there is hope that understanding the psychiatric comorbidities in movement disorders will lead to a better quality-of-life.

Cognitive and behavioral changes in Huntington disease before diagnosis

Phenotypic manifestations of Huntington disease (HD) can be detected at least 15 years prior to the time when a motor diagnosis is given. Advances in clinical care and future research will require consistent use of HD definitions and HD premanifest (prodromal) stages being used across clinics, sites, and countries. Cognitive and behavioral (psychiatric) changes in HD are summarized and implications for ongoing advancement in our knowledge of prodromal HD are suggested. The earliest detected cognitive changes are observed in the Symbol Digit Modalities Test, Stroop Interference, Stroop Color and Word Test-interference condition, and Trail Making Test. Cognitive changes in the middle and near motor diagnostic stages of prodromal HD involve nearly every cognitive test administered and the greatest changes over time (i.e., slopes) are found in those prodromal HD participants who are nearest to motor diagnosis. Psychiatric changes demonstrate significant worsening over time and remain elevated compared with healthy controls throughout the prodromal disease course. Psychiatric and behavior changes in prodromal HD are much lower than that obtained using cognitive assessment, although the psychiatric and behavioral changes represent symptoms most debilitating to independent capacity and wellness.

The Confluence of Psychiatric Symptoms and Neurodegenerative Disease: Impact on Genetic Counseling

Hereditary neurodegenerative diseases can present with a psychiatric prodrome that overlaps with psychiatric symptoms that are not primary to these diseases. When individuals present for predictive testing while experiencing such symptoms, clinicians including genetic counselors, must proceed with caution and evaluate each situation on a case-by-case basis. Legitimate reasons may exist for moving forward with testing. Additionally predicting the consequences of testing is unrealistic so that the clinicians must do their best to prepare patients for both positive and negative results. A multidisciplinary team following the Huntington disease protocol remains the gold standard care for predictive testing for such patients. We discuss 3 case histories that demonstrate the complex nature of genetic counseling and testing in the presence of psychiatric symptoms, whether emanating from the disease itself or the results of living in an affected family.

Changes in mental state and behaviour in Huntington's disease

Changes in mental state and behaviour have been acknowledged in Huntington's disease since the original monograph in 1872 provided evidence of disinhibition and impaired social cognition. Behavioural problems can manifest before obvious motor symptoms and are frequently the most disabling part of the illness. Although pharmacological treatments are used routinely for psychiatric difficulties in Huntington's disease, the scientific evidence base for their use is somewhat sparse. Moreover, effective treatments for apathy and cognitive decline do not currently exist. Understanding the social cognitive impairments associated with Huntington's disease can assist management, but related therapeutic interventions are needed. Future research should aim to design rating scales for behaviour and mental state in Huntington's disease that can detect change in clinical trials. Generally, communication and understanding of behaviour and mental state in Huntington's would be enhanced by a clear conceptual framework that unifies ideas around movement, cognition, emotion, behaviour, and mental state, reflecting both the experience of the patient and their underlying neuropathology.