Psychiatric Problems are a Part of HD Pathology
Huntington’s disease is conventionally recognizable for its motor implications. Indeed, chorea, or involuntary, irregular, and unpredictable muscle movement, is a hallmark symptom of the disease. However, psychiatric and behavioral symptoms are also important presenting signs of HD.1 Psychiatric symptoms are incredibly common in HD patients and often present preceding the onset of motor impairments.2 Some researchers have even raised the possibility of psychiatric symptoms caused by neurodegenerative changes as an early indicator of HD; depression can occur up to 20 years before the onset of motor impairments.34
These psychiatric comorbidities, even in isolation, can have significant negative costs, contributing to increased disease burden, lower quality of life, social isolation, functional decline, increased costs of care, and increased caregiver burden.5 It’s also important to note that these psychiatric problems can also have impacts in other respects. For example, treatments for a psychiatric comorbidity may have a negative effect on motor implications6 and physical pain caused by HD has also been found to be associated with anxiety and depression rates.7 Conversely, drugs used to treat chorea such as tetrabenazine and amantadine can cause depression and anxiety.8
Types of Psychiatric Issues in HD
There are a myriad of psychiatric issues that can occur in HD, but they typically fall into three distinct categories:
1. Conditions commonly found in the general non-HD population
The first category includes depression, anxiety, obsessive compulsive disorder, and psychosis. Sexual dysfunction and suicidal ideation are also symptoms that are more commonly found in HD patients than in the general population.5
2. Conditions commonly found in neuropsychiatric patients
The second category of psychiatric issues comprises problems uncommon in the general population but common in those with diseases affecting the frontal lobe and/or sub-cortical areas of the brain (e.g., Alzheimer’s). Disease-specific personality and behavioral changes are almost ubiquitous in HD. These changes are collectively called hypofrontal syndrome, dysexucutive syndrome, or organic personality syndrome. This syndrome is characterized by apathy, irritability, impulsivity, and obsessionality.6 Although these changes are not always obvious enough to be noticed during regular physician visits, they can have serious consequences for a HD patient’s social and financial life.
3. Difficult to characterize conditions
This last category includes complex phenomena such as delirium, “agitation,” or sexual disorders.
Treatment of Mental Illness in HD
Although clinicians need to be aware of how different drugs interact with HD symptomatology, mental illness in HD is generally treated just like any non-HD psychiatric issue. HD itself is not a barrier preventing conventional treatment. For HD patients presenting with organic personality disorder, caregiver psychoeducation is often used to aid treatment.
- Morreale, M.K.., “Huntington’s Disease: Looking Beyond the Movement Disorder” Clinical Challenges in the Biopsychosocial Interface.
- Julien, et. al., “Psychiatric disorders in preclinical Huntington’s disease” Journal of Neurology, Neurosurgery & Psychiatry.
- Folstein, et. al., “Conduct disorder and affective disorder among the offspring of patients with Huntington’s disease” Psychological Medicine.
- Watt, D. and Seller, A., “A clinico-genetic study of psychiatric disorder in Huntington’s chorea” Psychological Medicine.
- Rodriguez, T., “Addressing Neuropsychiatric Symptoms in Huntington Disease: Expert Interview” Movement Disorders Advisor.
- HDSA, “BEHAVIORAL / PSYCHIATRIC SYMPTOMS” HDSA.
- Underwood, M., “Huntington’s Disease: Prevalence and Psychological Indicators of Pain” Movement Disorders.
- Coppen, E. and Roos, R., “Current Pharmacological Approaches to Reduce Chorea in Huntington’s Disease” Drugs.