Behaviour and Mental Health in Huntington’s Disease

Behaviour and mental health in Huntington’s: the part that breaks everything

Ask families what the hardest part of Huntington’s disease is and very few of them say the chorea.

They say the temper. The apathy that looks like not trying. The accusations. The fixed ideas that cannot be shifted. The person who used to be warm becoming somebody who is not. The fact that the illness arrived in the form of a character change, years before anybody could point to a scan or a gene test, and that by the time there was a diagnosis the marriage had ended and the children had stopped visiting.

This is the domain that costs people their jobs, their relationships, their housing and sometimes their liberty, and it is the domain that determines whether a support arrangement holds or collapses.

It also has a feature that distinguishes it from the rest of Huntington’s: the psychiatric symptoms do not track the motor and cognitive decline. GeneReviews notes they tend not to progress as steeply. Which means somebody can be physically mildly affected and psychiatrically severely affected, or the reverse, and the stage of the movement disorder tells you almost nothing about how hard the behaviour will be.

And the single most important thing in this guide: much of this is treatable. Depression, anxiety, irritability, obsessive symptoms and sleep disturbance all respond to treatment, and treating them is frequently the highest-value intervention available in Huntington’s disease. More value than anything done for the chorea.

A note before starting. This guide discusses depression and suicide risk, because they are clinically important in Huntington’s and because families and support workers need to know about the periods of elevated risk. It does so without detail of methods. If any of it is affecting you, Lifeline is on 13 11 14, and Huntington’s Australia on 1800 244 735 can connect you with people who understand this condition specifically.

What the psychiatric picture consists of

Depression. Affects around 40 per cent of people with Huntington’s disease — the most common psychiatric symptom, and at more than twice the rate of the general population. It frequently appears before any motor symptom, which is why so many people with HD are treated for depression for years before anybody asks about family history. It is not simply a reaction to the diagnosis; it is part of the disease, arising from the same neurological changes.

Anxiety, the second most common.

Apathy. Common, and worsening with disease stage. Discussed at length below because it is the most misread symptom in the condition.

Irritability, explosiveness and aggression. Frequent. A short fuse, disproportionate reactions, verbal and sometimes physical aggression, usually directed at the people closest to the person.

Personality change and disinhibition. Loss of social filter, tactlessness, inappropriate remarks, sexual disinhibition in some people, loss of the judgment that used to govern what gets said and done.

Obsessive and perseverative behaviour. Getting stuck — on a topic, a demand, a grievance, a routine, a question asked forty times. This connects directly to the loss of set-shifting described in cognitive change in Huntington’s.

Delusions, commonly paranoid, and often about the people providing care — theft, infidelity, conspiracy. Hallucinations are less common. Frank psychosis can occur in later stages.

Suicide and suicidal ideation. Common in Huntington’s disease, and GeneReviews is specific about the timing: risk peaks around the time of diagnosis, and when people lose independence. Those two periods — the months after being told, and the transitions where driving, work, living alone or self-care are given up — are when attention matters most. Both are foreseeable, which means they can be prepared for.

Apathy is not laziness, and it is not depression

If one thing in this guide gets read, it should be this.

Apathy is a loss of initiation: the mechanism that converts an intention into an action has been damaged. The person is not sad. They are not hopeless. They are not refusing. They have not given up. The intention exists and the step from intention to movement does not happen.

How to tell it from depression: somebody who is depressed describes low mood, hopelessness, guilt and loss of pleasure, and typically does not enjoy an activity even when it happens. Somebody with apathy will frequently engage and enjoy an activity once it is started for them, and does not describe themselves as miserable. The distinction matters because the treatments differ, and because they frequently co-exist.

Why it does so much damage. Because apathy reads unmistakably as not trying. A partner who has organised an outing, cooked a meal, arranged a visit from the grandchildren, and gets no response, experiences that as indifference — and after a few hundred repetitions, as rejection. Resentment follows. Then guilt about the resentment. Families describe this as the thing that wore them down more than any physical care.

What helps:

Start things for them. Do not ask “would you like to go for a walk?” — put their shoes in front of them and say “let’s go for a walk.” The difference in outcome is enormous and it is not manipulation; it is providing the step that is missing.

Structure and routine, so that activities happen because it is Tuesday rather than because somebody decided to.

Prompt each step rather than the whole task.

Treat the depression if it is also there, which it often is.

Ask about medication. Amantadine, atomoxetine, methylphenidate, modafinil, bromocriptine and bupropion are all used for apathy in HD, with modest but real effects. Worth trying, and worth reviewing honestly.

Check what is making it worse. Antipsychotics and tetrabenazine can both deepen apathy, and in HD both are commonly prescribed. If apathy worsened after a medication change, say so.

And tell the family what it is. Simply knowing that apathy is a neurological symptom rather than a choice changes how people experience it, and that is one of the most useful things a clinician can do in this condition.

Irritability, aggression and what is actually happening

The mechanism. Loss of inhibition, reduced cognitive flexibility, perseveration, and a reduced capacity to tolerate frustration — all frontal. Add to that a person who is being asked to do things they can no longer do, by people who keep correcting them, in a situation they frequently cannot fully perceive, and the irritability is not mysterious.

The pattern is almost always the same. An escalation preceded by a trigger that was predictable. The commonest triggers:

Being rushed. Processing is slow; pressure produces a blow-up.

Being corrected or contradicted. Particularly where insight is reduced, in which case the correction is baseless from the inside.

An unexpected change of plan.

Being asked a multi-part question, or given several instructions at once.

Too much noise, too many people, too much happening.

Fatigue, hunger, pain, needing the toilet, constipation. The ordinary unmet needs, which in HD are a very large share of behavioural incidents.

Being helped with something they believe they can do.

Late afternoon, as in almost every neurological condition.

What reduces it:

Remove the trigger rather than teach tolerance. This is the central principle and it is the opposite of standard behaviour support, for reasons covered below.

Absolute predictability of routine. Same order, same time, same people.

Warning before change. A day, then a morning, then ten minutes.

One thing at a time, and more time than seems necessary.

Do not argue. Where there is a fixed position and reduced flexibility, argument escalates and never resolves. Agree where you can, change the subject, come back later.

Walk away and come back, where it is safe to.

The same small group of workers. Covered below, and it matters more than any technique.

Rule out the physical. Pain, infection, constipation and sleep deprivation first, every time.

And treat it. Antipsychotics are used for irritability and aggression in HD, SSRIs for irritability and obsessive symptoms, and mood stabilisers such as lamotrigine or carbamazepine where mood is unstable. This is a medical problem with medical treatments and it should not be managed solely as a behavioural one.

Why generic behaviour support fails here

This is worth spelling out, because it is the reason so many HD support arrangements end badly.

Most positive behaviour support is built on a learning model: identify what the behaviour achieves for the person, teach a replacement behaviour that achieves the same thing more acceptably, and reinforce it. It is a good model and it works in many conditions.

In Huntington’s disease it is substantially closed off. Teaching a replacement strategy requires learning, retaining, recalling in the moment, inhibiting the old response, and flexibly selecting the new one — and executive dysfunction, perseveration, impaired set-shifting, slowed processing and limited insight all sit directly across that path.

So what happens in practice is that a plan is written around teaching the person to recognise their frustration and use a coping strategy, the person does not do it, and the file starts to record non-compliance. From there it is a short distance to increased medication, increased restriction, and a placement breakdown.

What works instead is almost entirely environmental and relational:

• Reduce demands rather than build tolerance for them
• Remove triggers rather than desensitise
• Absolute consistency of routine and of staff
• Warning before change, every time
• No arguing with fixed positions
• Far more time than seems reasonable
• Physical causes ruled out first
• And the same people, who know this person’s early warning signs

Which means the question to ask any behaviour support practitioner before engaging them is: how many Huntington’s disease plans have you written? If none, expect a generic plan. Huntington’s Australia on 1800 244 735 and the specialist HD services can point you to practitioners with the right experience, and this is worth the delay of finding one.

Restrictive practices in Huntington’s

Because behaviour is prominent and insight is reduced, HD generates restrictive practices more often than most conditions, and it is worth knowing the framework precisely.

The five regulated restrictive practices are seclusion, chemical restraint, mechanical restraint, physical restraint and environmental restraint. Using any of them in NDIS-funded supports requires a behaviour support plan written by an NDIS behaviour support practitioner, authorisation under the relevant state law, monthly reporting to the NDIS Quality and Safeguards Commission, and a documented strategy to reduce and eliminate the practice. An interim plan is required within one month and a comprehensive plan within six. Use without authorisation or a plan is a reportable incident. For the rules in full, see behaviour support and restrictive practices.

What this catches in HD specifically:

A locked front door or locked kitchen is environmental restraint.

A lap belt or harness in a wheelchair may be mechanical restraint, as distinct from prescribed postural positioning — a distinction that has to be documented by the prescribing occupational therapist. See movement and chorea in Huntington’s.

Padded bed rails may be mechanical restraint depending on purpose.

And chemical restraint, which in Huntington’s is genuinely nuanced. Medication given primarily to influence behaviour, rather than to treat a diagnosed condition, is chemical restraint. But antipsychotics in HD are legitimately prescribed for chorea, and legitimately prescribed for psychotic symptoms, and also sometimes used to manage irritability. The same drug can be any of the three. The only way this works properly is for the prescriber to document the clinical indication explicitly rather than leaving a support provider to infer it. Ask for that in writing, and ask for it to be reviewed, because an antipsychotic started for agitation three years ago and never revisited is a common and consequential finding.

And the point worth holding onto: restrictive practices are not automatically wrong. A locked kitchen may be the least restrictive option available and may be the thing that keeps somebody in their own home rather than in a facility. What is wrong is doing it without a plan, without authorisation, without review, and without a strategy to need it less.

Mood treatment, and the periods of elevated risk

Treat the depression. This is the most under-done intervention in Huntington’s disease. SSRIs and related medications are used for depression, anxiety, irritability and obsessive symptoms, and the response can be substantial. Psychological therapy, including cognitive behavioural approaches, has a role, though it needs adapting for executive impairment — shorter sessions, more structure, more repetition, more involvement of the family.

Know the two high-risk periods, because they are predictable. GeneReviews identifies them as around the time of diagnosis, and when independence is lost. The second one is worth unpacking: the losses that matter are the licence, the job, living alone, managing money, and self-care. Each of those transitions is a known risk point, and each of them is usually scheduled rather than sudden — which means support can be put in place beforehand rather than afterwards.

What to do around those transitions. Make sure somebody clinical knows it is happening. Bring the appointment forward rather than back. Make sure the person is not alone in the days around it. Ask directly how they are rather than assuming. And if a dopamine-depleting medication such as tetrabenazine has recently been started or increased, factor that in, because its association with depression is recognised.

And if you are worried about somebody now, do not wait for the next appointment. The GP, the HD service, the state mental health line or an emergency department are all reasonable. Lifeline is on 13 11 14. Being direct about the question is better than being careful around it.

For families: the mental health of the person with HD and the mental health of the household are not separate problems. Carers in Huntington’s families are frequently also at genetic risk themselves, often caring across two generations, and the ABC reported a Huntington’s Australia description of “feelings of loss, guilt, anger, burden and helplessness” with deepening isolation. Carer Gateway is on 1800 422 737. See families and children.