Psychiatric symptoms in Huntington's disease before diagnosis: The Predict-HD study

Background: Psychiatric disturbances are relatively common in manifest Huntington's disease (HD), but less is known about these symptoms in the earliest phase of the illness. Methods: This study examined self-reported psychiatric symptoms in a large sample (N = 681) of prediagnosed individuals who show the gene expansion for HD ("expansion-positive") compared with a sample of individuals who do not show the gene expansion but are at risk for HD ("expansion-negative"). Results: Using baseline Symptom Checklist 90-Revised (SCL-90-R) data from the Predict-HD study, expansion-positive individuals reported significantly more psychiatric symptoms (e.g., depression, anxiety, obsessive-compulsiveness) than expansion-negative individuals.Within the expansion-positive group, individuals with more motor signs had higher levels of psychiatric symptoms.The SCL-90-R scores had stronger relationships with reported abilities to perform activities of daily living than other markers of HD. Finally, when companions of the expansion-positive individuals also completed the SCL-90-R on the participants, there was considerable consistency in the ratings of psychiatric symptoms. Conclusions: Subtle, subclinical psychiatric symptoms are present in this prediagnosed HD sample, even though most are estimated to be more than 10 years from HD diagnosis. As suggested by other research, these subtle symptoms might be the earliest markers of the disease; however, longitudinal data are needed.