Behavioural changes are a characteristic feature of HD which, although less obvious to the casual observer than the involuntary movements, represent for many families the most distressing aspect of the condition. Some alterations in the HD sufferer such as frustration, irritability and loss of confidence may occur to some extent as an understandable reaction to the presence of a disabling illness and to the loss of personal independence which it entails. However, behavioural changes also occur as an integral part of the disorder, arising as a direct result of changes that take place in the brain. Some of these changes arise as a direct result of alterations in the way a person thinks (intellectual changes); others represent alterations in a person’s mood.

Just as the nature and severity of the movement disorder varies from one HD sufferer to another, so too do behavioural symptoms. In some people alterations in behaviour are mild without major social impact However, in others they can be profound leading to disruption to family life and breakdown in social relationships, and placing a severe burden on carers. There are no easy solutions to difficult behaviour - precisely because the behaviour arises as part of the illness and is not under the patient’s control. Nevertheless, understanding the behaviour can help: it can lessen the burden and provide clues to the most appropriate methods of management.

Drive and Initiative

HD sufferers may show a loss of drive and initiative. If left to their own devices they may do nothing, stay in bed or spend the day watching television. This behaviour can be highly frustrating for family members, who may perceive the behaviour as "laziness" or the patient as "not pulling his/her weight". It can be a great source of family conflict when the patient’s partner is under stress from multiple responsibilities - for example, acting as breadwinner, caring for a young family, carrying out domestic chores.

It is important to recognise that the patient’s behaviour is not due to laziness. HD affects the part of the brain (the deep part of the brain or subcortex and its connections to the regions at the front of the brain) which are crucial for drive and initiative. These are the parts of the brain which allow us to think ahead, to make plans, to generate the actions appropriate to those plans, and to persevere on tasks until goals are achieved, the drive or foresight to self-initiate activity is severely compromised, even though the skill to carry out the activity is still retained. The patient may potentially be capable of carrying out a task, yet is unable to generate the motivation or initiative to embark on it.

Arguing with the patient will not overcome his/her difficulty. Encouraging joint participation in activities e.g. helping with the washing up, may be helpful and is generally more successful than assigning the patient solitary pursuits. This is because the other participants in an activity act as an external stimulator or motivator. The patient does not have to rely on his/her own drive and initiative. Participation is important. Not only does it help to keep the patient active, it also helps to provide a sense of worth - that the patient is able to make a constructive contribution.