Overview of HD’s Behavioral and Psychiatric Symptoms
People with HD may suffer from depression and other conditions found in the general population, such as mania, obsessive compulsive disorder, or various forms of psychosis. However, almost all people with HD will manifest disease-specific personality and behavioral changes as part of what might be termed a hypofrontal or dysexecutive syndrome, characterized by apathy, irritability, impulsivity, and obsessionality, with potentially severe consequences for the HD person’s marital, social,and economic well-being.
The disorders of HD cannot be considered in isolation. Disabilities in one area will lead to problems in another. For example, treatments for the psychiatric disorder may have a negative impact on the movement disorder. Changes in cognition have an effect on the ability to perform physical tasks such as driving or cooking. Few other diseases have this level of interconnected disabilities, affecting all areas of an individual’s life.
Psychiatric symptoms have long been understood to be a common and inherent part of Huntington’s disease. In the classic description of the condition which bears his name, George Huntington referred to “the tendency to insanity, and sometimes that form of insanity which leads to suicide…”Most physicians understand this in the abstract, yet people with HD with psychiatric problems suffer from under-diagnosis and under-treatment. This is regrettable, because psychiatric problems in HD are often the most disabling and yet the most treatable.
Categorizing Psychiatric Issues in HD
Psychiatric problems in HD tend to fall into three categories:
- The first consists of mental illnesses which are common in the general population and are readily recognized by physicians, especially major depression, which has been estimated to affect 40% of people with HD at some point during their illness. Other frequently encountered syndromes may include mania, obsessive compulsive disorder, and various delusional and psychotic disorders.
- The second category consists of psychiatric problems which are not often found in the general population but are common in neuropsychiatric patients, particularly those with injuries and diseases affecting the sub-cortical areas of the brain or the frontal lobes, such as HD, strokes, Parkinson’s disease, head injuries and various forms of dementia. This usually takes the form of a constellation of behavioral and personality changes which can include apathy, irritability, disinhibition, perseveration, jocularity, obsessiveness, and impaired judgment. These changes are collectively described by various names including organic personality syndrome, frontal lobe syndrome, or dysexecutive syndrome, which will be the erm used here. These changes are not always severe or obvious enough to be apparent to physicians during regular office visits, but the syndrome is so common in HD as to be virtually universal. n Finally, there are those psychiatric issues, such as delirium, “agitation,” or sexual disorders, which are difficult to characterize, perhaps because they depend so heavily on the interaction between the person with HD, the disease, and the environment.