Note: This section addresses some possible causes of specific HD behaviors. For a more complete description of the possible causes of general behavioral changes asscoiated with HD, read Part 2 of this chapter.
Characterized by indifference or lethargy, apathy is one of the most common behavioral symptoms of Huntington’s Disease. An apathetic individual may seem to have a diminished concern for things he or she used to care about. The individual may seem uninterested in his or her surroundings and lose enthusiasm as well as spontaneity. A lack of motivation and loss of the ability to initiate conversation or activities also tends to occur in individuals suffering from apathy.
Coping with apathy can be very difficult for caregivers as well as for the affected family member. Families may feel that he or she is no longer the same person they knew because of the loss of interest in activities that were previously enjoyed. Apathy can also be a frustrating symptom of HD because a caregiver may feel that the person with HD is capable of performing an activity but “won’t.”
Although the inability to initiate conversation or activity can occur independently, it tends to accompany apathy. The ability to initiate is a very complex brain function. Apathy appears to be caused by changes in the brain due to HD. The middle and bottom sections of the frontal lobes are connected to the limbic system, a part of the brain that is associated with emotions. HD leads to damage of a structure called the caudate nucleus, which may serve as a relay station for some of the messages being sent from the limbic system to the frontal lobes. As HD progresses, some of the connections from the caudate to the frontal lobes and limbic system are destroyed, potentially causing the frontal lobes to be disconnected from the “emotions” of the brain. As a result, the ability to self-initiate an activity is compromised, but the ability to perform the activity is retained.
Although aspects of apathy resemble depression, there are important distinctions. (see depression below) Many patients suffering from apathy deny being sad. Once the initiative is provided, the person is usually capable and willing to be involved in a particular activity. To read an article about techniques for motivating individuals with HD, click here.
Depression is often dismissed as an understandable reaction to being diagnosed with Huntington’s Disease. While a saddened mood is an understandable response to the life changes and loss of abilities resulting from HD, research and clinical experience show that many HD patients do not suffer from clinical depression. However, when depression does occur in HD, it often appears to be the direct result of changes in the brain caused by the disease. Brain changes due to HD can alter neurotransmitters, the chemicals that regulate moods. Thus, depression in HD is partly biological and partly situational, as an affected individual becomes aware of the life changes that may result from HD.
One of the challenges in managing depression for a person with HD is the diagnosis. Unfortunately, many of the symptoms of HD, such as memory loss, weight loss and apathy, resemble the symptoms of depression, thus making it potentially difficult to diagnose depression in an individual who has HD. Because patients with HD often have difficulty describing their emotional state, a specific complaint of a depressed mood is usually not necessary to diagnose depression. Following is a list of possible signs and symptoms of depression:
Lack of interest in usual activities
Sleeping most of the day or rarely sleeping
Depressed mood most of the day, nearly every day
Weight loss
Slower movements or speech
Feelings of worthlessness
Social withdrawal
Inability to concentrate
Recurrent suicidal thoughts
Loss of sex drive
The suicide rate for persons suffering from HD is seven times the national average. If a person with HD may be depressed, it is recommended to contact his or her physician. For a list of risk factors for suicide and suicide prevention tips, click here.
Depression is very treatable. Generally, physicians recommend aggressive treatment of depression in persons with HD. Treatment of depression can greatly improve one’s quality of life and significantly reduce the risk of suicide. Depression may precede the onset of other symptoms, and treatment may improve other problem behaviors. For more treatment information, click here.
Although some people suffering from HD may remain even tempered, others may lose the ability to control their emotions. Emotional volatility may be evident in increased irritability or episodes of explosiveness. A study on mice with the HD allele of the Huntington gene found that mice portrayed abnormal social behavior, particularly chronic aggressive behavior. For others, rigidity of thinking causes the individual to focus on one particular request. This individual may become irritable, frustrated or aggressive if demands are not met. To read more about the study on mice with the HD allele, click here.
When the caudate nucleus has deteriorated, emotions are improperly regulated, causing an increase in feelings of frustration and irritability. These feelings are often legitimate and triggered by something in the environment. The brain, however, cannot control the intensity of the emotion. Several factors may contribute to the feelings of intense frustration, etc:
Hunger
Pain
Inability to communicate
Changes in routine
Loss of ability to perform certain tasks
HD causes changes in the brain that often make it difficult for a person with HD to see another’s point of view. As a result, the individual may become easily frustrated or irritated if his or her views or ideas are challenged. A person with HD can rapidly escalate into severe anger; however, he or she can also calm down very quickly. If you would like to read about one woman’s personal experience of dealing with a husband suffering from these behavioral symptoms, click here.
Disinhibition is the inability to control a sudden desire to do or say something. When these desired actions or words are potentially hurtful, repetitious or socially inappropriate, disinhibition may be considered a problem behavior. Making a comment to a co-worker about the supervisor’s horrible hair-do while she is within earshot is an example of a disinhibited behavior. Generally, these behaviors are unintentional. The damage to the caudate nucleus may cause this difficulty in controlling emotions and impulses. Damage to the caudate may also result in the inability to experience intense feelings of embarrassment, guilt or shame.
In certain circumstances, a repetitious behavior or an impulsive behavior, such as a temper tantrum, may be an inappropriate response to something in the environment or a change in routine that needs to be addressed. An unreliable routine can contribute to disinhibition, such that mild feelings of confusion or annoyance are expressed as intense feelings of anger or fear. For more information on frustration, irritability and aggression, click here.
Following damage to the basal ganglia and the caudate nucleus, individuals with HD may become “stuck” on one idea or activity. Inflexible thoughts and behavior may also make it difficult for an individual to change from one activity or idea to another or to deal with changes in routines. These behaviors are often associated with Obsessive-Compulsive Disorder (OCD). True OCD, however, is uncommon in HD patients. Another possible cause of repetitive behavior is that legitimate needs of the individual are not being met. He or she may repeat a request in hopes of being understood.
While it is common for an individual with HD to experience anxiety about the future, sometimes excess worry occurs over seemingly trivial matters. Anxiety, a behavioral symptom of HD, is characterized by:
Nervousness
Restlessness
Fidgeting
Shallow breathing
Sweating
Fear
Panic
Rapid heart-rate
Repetitive thoughts about bothersome topics
For individuals with HD, continual life changes as HD progresses can be a source of anxiety. Some individuals become anxious about social engagements because they are embarrassed about visible symptoms, such as chorea. However, physical brain changes caused by the disease itself may also cause excessive anxiety. As thought processes become less flexible, changes in routine can exacerbate anxious behavior. Often, a calm, predictable environment can effectively minimize some behavioral symptoms.
The term "denial" is most commonly used to describe the inability to accept the reality of a distressing circumstance. HD sufferers may deny having HD or may be unable to recognize their disabilities. However, such denial is not under the individual’s control, so “unawareness” may be a more accurate term for people with HD.
As a result of the HD mutation, circuits connecting the caudate nucleus, frontal and parietal lobes may incur damage, resulting in a lack of self-awareness. People with HD may be unable to recognize disabilities or evaluate their own behavior. The inability to evaluate one’s own performance may cause individuals to be unaware of mistakes that are evident to others. Damage to these neural connections may also impair the ability to experience a range of subtle emotions and see another’s point of view, making social and personal relationships more difficult.
A lack of awareness often plays a role in seemingly irrational behaviors. For example, a person may become upset if he or she is not allowed to go back to work or live independently, because of the unawareness of failing capabilities. However, a person may be willing to talk about his or her capabilities, but unable to acknowledge that failing capabilities are the result of HD. Unawareness, a cognitive as well as a behavioral symptom, is currently accepted as an untreatable component of HD.
Hallucinations, delusions and mania are very rare behavioral symptoms of HD. Hallucinations involve seeing, hearing or experiencing things that are not real, such as feeling bugs crawling on you, hearing voices, etc. Thinking that someone is out to get you or that someone is watching you are examples of delusions. Delusions are defined as thoughts about unreal situations.
Many hallucinations or delusions are benign, meaning that they are not bothersome or harmful to the person experiencing them. If an individual is staring out into space and laughing at something that appears to be in front of them, this is a non-bothersome hallucination. However, this is not to suggest that the hallucination or delusion is non-bothersome to a caregiver. Occasionally, more severe hallucinations or delusions occur and may cause extreme fear or paranoia. In these cases, medical treatment can be sought.
Mania is also a very rare symptom of HD. Characterized by an irritable mood, overactivity, decreased need for sleep and impulsiveness, mania can drastically upset one’s daily routine. Sometimes a period of mania is followed by a period of depression (see depression above), referred to as Bipolar Disorder. Mania and Bipolar Disorder can be treated with medication. For more information on the medical treatment of any one of these three behavioral symptoms, a psychiatrist can be consulted.
A very common behavioral symptom of HD is altered sexuality. One possible cause of this symptom is that HD damages the brain’s ability to regulate the amount of sex drive a person has. Another possible cause is that the delicate balance of hormones in the brain is disrupted by the progression of HD, causing changes in behaviors regulated by hormone levels. Most commonly, people with HD suffer from a decreased sex drive. Increased sex drive and inappropriate sexual behavior are less common alterations of sexuality resulting from HD.
While altered sexuality can be due to the progression of HD, a decreased sex drive may also be caused by depression or apathy, other behavioral symptoms of HD. Inappropriate sexual behavior can be secondary to disinhibition. However, the inheritance of HD does not cause an end to one’s sexuality. For more information regarding altered sexual behaviors associated with HD and an account of personal experiences with this behavioral symptom, click here.
Last Modified: 1-01-03
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