Psychiatric manifestations of Huntington’s disease
Huntington’s disease is characterized by motor, cognitive, and behavioral disturbances (Table 22,4). Motor symptoms include a characteristic and well-recognized chorea, often predominating earlier in HD, that progresses to rigidity, spasticity, and bradykinesia later in the disease course.2 Cognitive impairments develop in a similar progressive manner and can often precede the onset of motor symptoms, beginning with early executive dysfunction. Thinking often becomes more rigid and less efficient, causing difficulty with multi-tasking and concentration, and often progressing to subcortical dementia.2
Psychiatric symptoms have long been recognized as a feature of HD; the estimated lifetime prevalence in patients with HD ranges from approximately 33% to 76%.4 Depressed mood, anxiety, irritability, and apathy are the most commonly reported symptoms, while a smaller percentage of patients with HD can experience obsessive-compulsive disorder (10% to 52%) or psychotic symptoms (3% to 11%).4 A more specific schizophrenia-like psychosis occurs in approximately 3% to 6% of patients, and often is a paranoid type.5,6 Positive psychotic symptoms, such as hallucinations and delusions, typically become less overt as HD progresses and cognitive impairments worsen.7
Although the onset of motor symptoms leads to diagnosis in the majority of patients with HD, many patients present with psychiatric symptoms—most commonly depression—prior to motor symptoms.8 An increasing body of literature details instances of psychosis preceding motor symptom onset by up to 10 years.6,9-12 In many of these cases, the patient has a family history of HD-associated psychosis. Family history is a major risk factor for HD-associated psychosis, as is early-onset HD.7,9
TREATMENT Antipsychotics result in some improvement
On Day 1 or 2, Mr. J is started on risperidone, 1 mg twice daily, to manage his symptoms. He shows incremental improvement in thought organization. Although his religious and grandiose delusions persist, they become less fixed, and he is able to take the team’s suggestion that he reconnect with his family.
Mr. J is aware of his family history of HD and acknowledges that multiple relatives had early psychiatric manifestations of HD. Despite this, he still has difficulty recognizing any connection between other family members’ presentation and his own. The psychiatry and neurology teams discuss the process, ethics, and implications of genetic testing for HD with Mr. J; however, he is ambivalent regarding genetic testing, and states he would consider it after discussing it with his family.
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