Behavioral and Psychological manifestations of Huntington's Disease

1. Huntington’s Disease and Its
Behavioral and Psychiatric Effects
By Uzair Ahmed

2. Introduction
• Huntington's disease (HD) is
a neurodegenerative genetic disorder that affects
muscle coordination and leads
to cognitive decline and behavioral symptoms.
• HD is the most common genetic cause of
abnormal involuntary writhing movements
calledchorea, which is why the disease used to be
called Huntington's chorea.

3. Cause:
• HD is one of several trinucleotide repeat
disorders which are caused by the length of a repeated
section of a gene exceeding a normal range, a genetic
defect on chromosome no. 4.
• Generally, people have fewer than 36 repeated
glutamines which results in production of
the cytoplasmic protein Huntingtin. However, a
sequence of 36 or more glutamines results in the
production of a protein which has different
characteristics.This altered form, called mHtt (mutant
Htt), increases the decay rate of certain types
of neurons.

4. Inheritance:
• Huntington's disease has autosomal
dominant inheritance, meaning that an affected
individual typically inherits one copy of the gene
with an expanded trinucleotide repeat (the
mutant allele) from an affected parent.
• In this type of inheritance pattern, each offspring of
an affected individual has a 50% risk of inheriting
the mutant allele and therefore being affected with
the disorder.
• As the disease is passed along in families, it becomes
evident at younger and younger ages.

5. Signs and Symptoms:
• HD is considered a tripartite neurodegenerative
disorder, with motor, cognitive, and psychiatric
changes.
• Appear between age 30-50
• Common physical symptoms are uncontrollable
rapid jerky movements , minor twitching in
fingers and toes, poor balance, slurred speech,
difficulty swallowing, and sensory sypmtoms like
numbness and pain.

6. The Behavioural and Psychological Symptoms
of HD (BPSHD)
• BPSHD are part of the disease process and present
severe problems to those with HD, their families and
caregivers, and wider society.
• Apathy,
• depression,
• lack of insight,
• disinhibition,
• impulsivity,
• obsessive and compulsive symptoms,
• anxiety,
• frustration,
• irritability,
• and aggression.

7. Causes of the BPSHD
• There are multiple causes of the BPSHD, with underlying factors including a
combination of the following:
• Neurobiological factors
neurochemical and neuropathology, current health status, presence of
coexistent medical or psychiatric syndromes, such as delirium, urinary tract
infections, arthritis, insomnia,dehydration.
• Cognitive factors – cognitive impairment
• Psychological factors – personality traits, response to stress
• Social factors – changes in family structure, leaving work, changes in routine,
stigmatisation and exclusion
• Environmental factors – changes in caregiver, moving house, unmet needs
of the person with HD, such as the presence of pain, wetness, fatigue, or fear.

8. The common BPSHD
• There are many ways in which the BPSHD can
be grouped, including in symptom clusters,
function, or altered behaviour.
1. Affective (Mood-related) Sypmtoms
 Apathy/ Indifference / lack of motivation
 Depression / Suicidal tendency
 Agitation / Aggression
 Anxiety and stress

9. 2. Perceptual Symptoms & Mania
 Psychotic symptoms like halucinations, which can
involve sounds (especially voices), visions, olfactory
(smells), gustatory (taste) and tactile (feeling of
being touched).
 Mania : People with HD may become manic,
displaying elevated or irritable mood, impulsiveness,
overactivity, decreased need for sleep, and grandiosity.
Symptoms include increased levels of activity,
pressured speech, uncharacteristic cheerfulness, large
and inappropriate purchases, and a return of sexual
interest after a long period of an inability to experience
pleasure or impotence.

10. 3. Personality Symptoms
 Disinhibition & Impulsivity :
Disinhibition has been associated with impulsive and inappropriate behaviours.
People who are disinhibited have trouble controlling a sudden desire to do or say
something that comes to mind, even if the behaviour is inappropriate, hurtful, or
repetitive.
 Perseveration, Obsessive-Compulsive behaviour, Inflexibility & Self-Centeredness:
Some people with HD appear to have an inability to see things from another person’s
point of view. They can appear to be self-centred and selfish.
A person with HD may be perseverative or often become “stuck” on an idea or
activity. They can be rigid in their behaviour and struggle to change, adapt, and/or alter
routine.
 Frustration & Irritability
Frustration may be caused by clumsiness or difficulties with communication, and
also due to physical factors such as hunger and fatigue.
Irritability is typically manifested by verbal outbursts, threatening behaviours,
aggression, and inflexible/uncooperative behaviour. Bad-tempered outbursts and
irritability are among the most common and troublesome BPSHD.
 Altered Sexuality

11. 4. Unawareness, Denial, & Lack of Insight
A lack of self awareness and an inability to evaluate
one’s own performance may cause individuals to be unaware of
mistakes that are obvious to others.
 People with HD may have reduced capacity for self-reflection and
insightfulness.
 Deny having HD or accept this reality and accept their
symptoms.
 be unable to recognize their own disabilities or to evaluate
their own behaviour and limitations. This can result in anger
as some people with HD cannot understand why they can no
longer, say, drive or work.

12. Treatment and Management
of the BPSHD
BPSHD are treatable and are often more amenable to therapy
than any other symptoms of HD. Therefore role of family as
well as professional caregiver and psychiatrist is very
important in the management of BPSHD.
 Pharmacological Management :
Medication is typically used for moderate to severe
BPSHD. When considering using medication in a person with
HD, consideration must be given to their age and the disease-related
changes.
Review of the medication regimen is also recommended
at 12 week intervals, in order to measure efficacy (effect of the
frequency and severity of the symptom) and its side effects.

13. Prognosis:
• Life expectancy in HD is generally around 20 years following the
onset of visible symptoms. The earlier the symptoms appear in life,
the faster the disease progresses!
• Most life-threatening complications result from muscle
coordination and, to a lesser extent, behavioral changes induced by
declining cognitive function.
• The largest risk is pneumonia, which causes death in one third of
those with HD. As the ability to synchronize movements
deteriorates, difficulty clearing the lungs and an increased risk
of aspirating food or drink both increase the risk of contracting
pneumonia.
• Suicide is the third greatest cause of fatalities, with 7.3% of those
with HD taking their own lives and up to 27% attempting to do so.
• Other associated risks include choking, physical injury from falls,
and malnutrition.