HONOLULU— Individuals who are at risk for Huntington’s disease and who have abnormal neurologic examination findings experience a higher level of overall depression than do those with normal neurologic findings, a study has concluded. When looking at specific signs of depression, however, researchers found that nonsomatic symptoms, including sadness and guilt, were significantly elevated in persons who are at risk for Huntington’s disease. In contrast, somatic symptoms of depression, such as sleep disturbance and decreased appetite, were more prominent in those with a confirmed diagnosis of Huntington’s disease.

“The findings replicate previous results in a different sample of Huntington’s disease patients using a different measure of depression, the Beck Depression Inventory,” said Karin Ferneyhough. In previous work by the authors, depression and suicidal ideation were measured using items from the behavioral section of the Unified Huntington’s Disease Rating Scale. “A trend toward greater somatic symptoms with increasing motor abnormalities was present, although it was not statistically significant, likely due to sample size considerations,” she noted. Ms. Ferneyhough, a graduate student in the Department of Psychology at the University of Iowa, presented her team’s findings at the 14th Annual Meeting of the American Neuropsychiatric Association.

THE COURSE OF DEPRESSION

Depression occurs in about 60% of patients with Huntington’s disease. Studies have suggested that depression and suicidal ideation may be particularly prevalent when motor symptoms of Huntington’s disease first appear. But, as Ms. Ferneyhough pointed out, “Relatively little research has characterized depression in different stages of the disease or examined different types of depressive symptoms.”

Depressive symptoms were assessed in 87 patients at risk for, or diagnosed with, Huntington’s disease. Participants were grouped based on diagnostic confidence ratings from the motor section of the Unified Huntington’s Disease Rating Scale. Forty patients had normal neurologic examination findings, 16 had abnormalities, and 31 had definite Huntington’s disease. Each patient’s total depression score, cognitive depression score, and somatic depression score from the Beck Depression Inventory were then compared across diagnostic groups.

Regarding the total Beck depression scores, post hoc tests showed a significant difference between individuals with a normal exam (6.5) and those at risk with an abnormal exam (14.1). For cognitive subscale scores, tests revealed that those with a normal exam had a Beck score of 4.3, while those at risk with an abnormal exam had a score of 10.3. Somatic subscale scores were significantly higher in the group with definite Huntington’s disease (4.0), compared with those at risk with a normal exam (2.1).

“These results are important in increasing understanding of the typical progression of depressive symptoms in Huntington’s disease,” said Ms. Ferneyhough. “Further, they shed light on the correlates of depressive symptoms in Huntington’s disease, which may lead to theories regarding the etiology of depression in general.”

MOTORING ALONG

In related research, Carissa Nehl, also a graduate student in the Department of Psychology at the University of Iowa, reported that depression severity was associated with motor abnormalities and cognitive decline prior to diagnosis of Huntington’s disease. This suggests that depression may be secondary to the neurobiology of Huntington’s disease “and not simply a reaction to distress,” said Ms. Nehl.

After finding that individuals with mildly abnormal motor exams (not enough to warrant a diagnosis of Huntington’s disease) experienced the highest rates of depression, she and her colleagues wanted to further examine depression in presymptomatic Huntington’s disease. They evaluated depressive symptoms in 71 individuals recruited from at-risk Huntington’s disease studies and from a clinic sample. No participant was diagnosed with the disorder, but 32 (45%) exhibited abnormal motor symptoms.

Ms. Nehl and colleagues found that motor severity ratings were strongly associated with Beck Depression Inventory score and that depressive symptoms were also associated with decreased cognitive performance. “The findings suggest that depressed mood may be due, in part, to an awareness of increased cognitive and motor abnormalities and impending Huntington’s disease diagnosis,” said Ms. Nehl. “These results are consistent with biologic and etiologic theories of depression in Huntington’s disease. Further research is needed to examine the biologic and reactive components of depression in the disease.”

Jane Paulsen, PhD, Professor of Psychiatry and Neurology at the University of Iowa and lead researcher of both studies, noted that the genetic status of all study participants was not known. She also said that the diagnosis of Huntington’s disease in the studies refers to a clinical diagnosis based on unequivocal motor abnormalities on a neurologic exam. “Depression is common in Huntington’s disease and in some cases can manifest prior to motor symptoms,” she said. However, depression is not required for the diagnosis “nor is it present in all individuals with Huntington’s disease.”

—Colby Stong

Suggested Reading
Ferneyhough KC, Stierman LM, Turner BM, et al. Critical periods of suicide risk in Huntington’s disease. J Neuropsychiatry Clin Neurosci. 2002;14:104.
Nehl C, Benjamin M, Paulsen JS, HSG Study Group. Rates of depressive symptoms in presymptomatic Huntington’s disease. J Neuropsychiatry Clin Neurosci. 2002;14:107.
Zappacosta B, Monza D, Meoni C, et al. Psychiatric symptoms do not correlate with cognitive decline, motor symptoms, or CAG repeat length in Huntington’s disease. Arch Neurol. 1996;53:493-497.

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