Changes in mood and behaviour form the most variable symptoms of the clinical characteristics of Huntington’s disease (HD). Although the diagnosis is usually based on motor signs, behavioural changes occur as a first manifestation of HD in up to half of the patients. 3 Irritable behaviour, aggression, and depression are most commonly seen in the first phase of the disease. Anxiety, obsessions, and apathy are also extremely common in HD. In certain families, major affective disorders may appear as early as 20 years before the onset of chorea and dementia. However, with regard to the manifestation of psychiatric signs, there is a known difficulty in distinguishing between an intrinsic and a reactive pattern. The action of the disease is often intertwined with the reaction to the disease in diagnosed patients but also in “asymptomatic” (that is, absence of motor signs) subjects carrying the expansion of the CAG triplet repeat (henceforth referred to as “carriers” compared to “non-carriers”). As far as we are aware, only two studies have been reported regarding psychiatric symptoms in asymptomatic carriers compared to noncarriers. 7 A controlled psychiatric study reported by Shiwach and Norbury showed that there was no significant increase in affective disorder in the former group. However, the whole predictive tested group showed a higher prevalence of psychiatric episodes than their partners. According to the authors it is, therefore, not plausible that depression is an early sign of HD in asymptomatic carriers. Depression and feelings of helplessness are indeed usually seen as a consequence of stressful events related to HD, like predictive testing in both carriers and non-carriers, even years after the predictive test result. Many studies have been reported on mood changes as a reactive pattern in both carriers and non-carriers, 9 but behavioural changes as a plausible first manifestation of HD have not been the subject of such extensive investigation. Only Berrios et al reported higher measures of irritability in neurologically asymptomatic carriers, suggesting that this symptom can appear very early in the course of HD. The focus of most investigators in this group has been directed more towards cognitive and motor functioning. 10–28 Differentiating between the behavioural changes inherent in HD and the well known impact of DNA testing is important in view of studying early markers of the disease onset. This is in line with Paulsen et al who stated “Careful study of neuropsychiatric symptoms associated with HD is essential to help distinguish features that are pathognomonic from behaviours that are sensitive but not specific of the disease”. Therefore in the present explorative study, we investigated the following issues. • Is there a difference between carriers and non-carriers in the outcome of the UHDRS behavioural assessment? • Do age and gender play a role in developing behavioural complaints? • Are a psychiatric history and the interval between DNA testing and first assessment associated with the development of behavioural complaints? • Is there a change in behavioural complaints in carriers after 18 months? Do these differ from non-carriers? Longitudinal investigation is needed because of the diagnostic inaccuracy in cross sectional assessment of patients, one reason being the variability in presentation early in the disease. Also, knowledge about the progression of psychiatric, motor, and cognitive symptoms and their relationship is essential for research into neuroprotective treatments.