--- title: "Huntington's Disease | Cognitive Psychology" description: "Huntington's disease is a hereditary neurodegenerative disorder that causes cognitive decline, chorea, and psychiatric changes in Cognitive Psychology." canonical: "https://fiveable.me/cognitive-psychology/key-terms/huntingtons-disease" type: "key-term" subject: "Cognitive Psychology" unit: "Unit 19" --- # Huntington's Disease | Cognitive Psychology ## Definition Huntington's disease is a hereditary neurodegenerative disorder in Cognitive Psychology that causes progressive motor, cognitive, and psychiatric decline. It matters because it shows how one genetic mutation can change thinking, memory, and behavior over time. ## What It Is Huntington's disease is a hereditary neurodegenerative disorder that damages brain cells over time and changes both movement and thinking in Cognitive Psychology. The classic picture includes involuntary movements called chorea, but the cognitive side is just as important. People can develop problems with attention, memory, planning, judgment, and mental flexibility as the disease progresses. The cause is a mutation in the HTT gene, specifically an expanded CAG repeat. That repeat makes the huntingtin protein abnormal, and the toxic effects build up slowly in the brain. Because it is autosomal dominant, a person with one affected parent has a 50% chance of inheriting the mutation. Symptoms usually appear in adulthood, often between ages 30 and 50, so someone may seem healthy for years before changes start to show. For cognitive psychology, Huntington's disease is useful because it shows that cognition is tied to brain systems, not just to effort or motivation. The disease especially affects circuits involving the basal ganglia and connected cortical areas, which helps explain why planning, response control, and mental speed can become harder. A person might know what they want to do but still struggle to organize steps, switch tasks, or stop an automatic response. The cognitive pattern is often broader than simple memory loss. Early on, a person may have slowed processing, trouble concentrating, or weaker executive function before major memory problems appear. That can make the disease look different from Alzheimer's disease, where memory is often the earliest and most obvious issue. In Huntington's, a student should think about a mix of motor symptoms, cognitive decline, and psychiatric changes rather than only one domain. A common classroom mistake is to treat Huntington's disease as only a movement disorder. In real cases, the thinking changes can affect work, daily planning, social interactions, and decision-making just as much as the chorea does. Treatment is mostly supportive and symptom-based, so the course tends to focus on how clinicians recognize the pattern and how the symptoms change quality of life over time. ## Why It Matters Huntington's disease matters in Cognitive Psychology because it connects brain degeneration to real changes in mental processes. It gives you a clean example of how damage to specific neural systems can affect executive function, attention, memory, and judgment, not just physical movement. This term also helps with differential thinking. If a case description includes adult onset, inherited risk, chorea, and cognitive slowing, Huntington's is often the best match. If the description leans more toward early memory loss and cortical shrinkage, you would think differently, so the term trains you to separate similar disorders by symptom pattern. It also shows why cognition is not one single ability. A person with Huntington's may still recognize people and remember some facts but struggle to plan, shift tasks, or inhibit responses. That kind of profile is a strong reminder that different brain systems support different parts of thinking. Finally, the disorder is a good example of how genetics, brain biology, and behavior connect. In essay questions, case studies, or discussion prompts, you can use Huntington's disease to explain why a genetic mutation can eventually change everyday cognition and behavior in a very specific, observable way. ## Connections ### Neurodegeneration Huntington's disease is one example of neurodegeneration, which means neurons gradually break down and die. In Cognitive Psychology, that process matters because it lets you connect symptom changes to the brain systems being damaged over time. Huntington's is especially useful for showing that degeneration can affect cognition, not just movement or memory. ### Chorea Chorea is the quick, involuntary movement pattern often linked with Huntington's disease. It is the most visible sign in many cases, but it is not the whole disorder. When you see chorea in a case description, pair it with the cognitive changes, since the disease usually affects both motor control and mental functioning. ### [Cognitive Reserve](/cognitive-psychology/key-terms/cognitive-reserve) Cognitive reserve helps explain why two people with the same brain disease may show symptoms at different times or with different severity. Someone with more reserve may compensate longer before cognitive problems become obvious. In Huntington's disease, this idea can help you think about why symptom onset and daily impact vary across individuals. ### [Neurotransmitter Dysfunction](/cognitive-psychology/key-terms/neurotransmitter-dysfunction) Huntington's disease disrupts normal brain signaling, so neurotransmitter dysfunction is part of the picture. When communication between neurons gets distorted, cognition and movement both suffer. This connection helps you understand why the disorder affects planning, impulse control, and other executive skills instead of producing only one isolated symptom. ## On the AP Exam A case-analysis question might describe an adult who has a family history of the disorder, begins showing chorea, and then develops trouble concentrating, planning, or making sound judgments. Your job is to identify Huntington's disease and connect the symptoms to neurodegeneration caused by an inherited gene mutation. If a question asks why cognition changes, point to the breakdown of brain circuits that support executive function and response control. In short-answer or essay work, you may be asked to compare Huntington's with another neurodegenerative disorder, explain autosomal dominant inheritance, or describe how the disease changes everyday functioning. The best responses name both the motor and cognitive signs, not just one or the other. ## Huntington's disease vs Alzheimer's disease These disorders both cause cognitive decline, but they usually show different early patterns. Huntington's disease often starts with chorea, executive dysfunction, and psychiatric changes in adulthood, while Alzheimer's disease more often begins with memory loss and progressive disorientation. If a prompt emphasizes inherited risk plus involuntary movements, Huntington's is the better match. ## Key Takeaways - Huntington's disease is an inherited neurodegenerative disorder that affects movement, thinking, and mood over time. - It is caused by an expanded CAG repeat in the HTT gene and is autosomal dominant, so one affected parent can pass it on. - In Cognitive Psychology, the term matters because it shows how brain degeneration can disrupt executive function, attention, memory, and judgment. - Chorea is a classic motor symptom, but the cognitive changes are just as important for diagnosis and daily life. - When you see adult onset plus family history plus worsening cognitive and motor symptoms, Huntington's disease is a strong possibility. ## FAQs ### What is Huntington's disease in Cognitive Psychology? Huntington's disease is a hereditary neurodegenerative disorder that causes progressive changes in movement, cognition, and behavior. In Cognitive Psychology, it is used to show how a genetic mutation can disrupt executive function, attention, memory, and response control over time. ### Why does Huntington's disease affect thinking? The mutation leads to brain cell damage in networks that support both movement and cognition, especially circuits involving the basal ganglia and connected cortical areas. That is why people can develop slower thinking, poor judgment, and trouble planning, not just motor symptoms. ### How is Huntington's disease different from Alzheimer's disease? Both are neurodegenerative, but they usually show different early signs. Huntington's disease often includes chorea and executive dysfunction, while Alzheimer's disease is more associated with early memory loss and disorientation. The family history and adult-onset movement symptoms are big clues for Huntington's. ### How would I use Huntington's disease in a psychology answer? Use it to explain a case with inherited risk, adult onset, involuntary movements, and cognitive decline. You can also use it to describe how damage to specific brain circuits changes planning, inhibition, and everyday decision-making. ## Related Study Guides - [19.4 Neurodegenerative Diseases and Cognition](/cognitive-psychology/unit-19/neurodegenerative-diseases-cognition/study-guide/16sokF7tAAxD2f0l) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/cognitive-psychology/key-terms/huntingtons-disease#resource","name":"Huntington's Disease | Cognitive Psychology","url":"https://fiveable.me/cognitive-psychology/key-terms/huntingtons-disease","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/cognitive-psychology/key-terms/huntingtons-disease#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:21:12.735Z","isPartOf":{"@type":"Collection","name":"Cognitive Psychology Key Terms","url":"https://fiveable.me/cognitive-psychology/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/cognitive-psychology/key-terms/huntingtons-disease#term","name":"Huntington's disease","description":"Huntington's disease is a hereditary neurodegenerative disorder in Cognitive Psychology that causes progressive motor, cognitive, and psychiatric decline. 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