Feelings of hopelessness and anxiety, in particular, increase the risk of suicidal ideation in individuals at high risk for Huntington’s disease, a recent study found. Other behavioral symptoms strongly linked to suicidal ideation included depression, irritability, aggression, and impulsivity, according to the researchers.
“It is helpful for clinicians, particularly those without mental health expertise, to know what factors increase risk of suicidal ideation in people from Huntington’s disease families, regardless of whether expansion mutation carrier status is known,” the authors wrote. “Additional questions about hopelessness [and] anxiety, and a careful neurological examination to look for very early signs of Huntington’s disease, may provide a more accurate picture of suicide risk.”
Previous research has reported completed suicide rates of 1.8% to 5.3% among individuals at a 50% risk of having Huntington’s disease. Karen E. Anderson, MD, of the departments of psychiatry and neurology at Georgetown University, and colleagues assessed 801 individuals who had a first-degree relative with Huntington’s disease. The participants had all declined genetic testing for themselves but agreed to allow DNA analysis for research. One-third of the participants had the cytosine-adenine-guanine (CAG) expansion mutation, determined based on a CAG of at least 37.
Dr Anderson’s team used the Beck Depression Inventory-II (BDI-II) and the Beck Hopelessness Scale to assess depression and hopelessness. Data for irritability, aggression, anxiety, and other behavioral symptoms came from the Unified Huntington’s Disease Rating Scale (UHDRS) behavioral subscale, and the UHDRS motor score was the source of neurological symptom assessment. Only 396 individuals underwent assessment of impulsivity, using a section from the Barratt Impulsivity Scale.
Of the participants, 40 had suicidal ideation (based on the BDI-II question about suicidal thoughts), which occurred in 6.3% of patients with the CAG expansion mutation compared with 4.3% of patients without it.
“CAG mutation expansion was not significantly associated with suicidal ideation in the current study, indicating that being at risk for Huntington’s disease notwithstanding mutant gene carrier status is a hazard per se for suicidal ideation,” the investigators wrote. Patients with suicidal ideation did show significantly increased depression, hopelessness, irritability, aggression, anxiety, and motor symptoms.
After calculations for all these behavioral factors and adjustments for CAG status, sex, and age, patients with hopelessness emerged with 25% greater odds of suicidal ideation than patients without it. Odds of suicidal ideation were more than doubled in individuals showing anxiety symptoms. Presence of motor symptoms, however, showed only a marginally significant association with suicidal ideation (P=.0525).
Although having the CAG mutation was not associated with a higher risk of suicidal ideation on its own, the researchers calculated odds for CAG groups separately. Hopelessness, irritability, and anxiety all remained significantly predictive of suicidal ideation in patients without the mutation, but only hopelessness remained significantly predictive in individuals with the CAG expansion. Again, in the latter group, motor symptoms were only marginally significant (P <.0714).
Among the smaller group assessed for impulsivity, this trait also emerged as significant for predicting suicidal ideation.
Limitations of the study aside from self-reporting include potential selection bias among the participants and their visits at Huntington’s disease centers, “so that psychiatric symptoms were likely detected and treated rapidly, possibly lowering suicidal ideation,” the researchers noted.