The aim of the study is to assess the epidemiology of psychiatric symptoms in patients with Huntington Disease (HD).

All patients affected by HD attending our Movement Disorder Clinic in a 3-year period were evaluated by the Unified Huntington’ Disease Rating Scale and by the BPRS.

Among 70 patients, 61 (87.1%) presented depressive symptoms in the course of illness, 56 (80.0%) anxiety, 36 (51.4%) manic symptoms, 47 (67.1%) irritability, 15 (21.4%) delusions, 9 (12.4%) hallucinations, 23 (32.9%) obsessivecompulsive symptoms, 57 (83.7%) apathy, 28 (40%) aggressiveness/violence, 26 (37.1%) suicidality, and 29 (41.4%) dementia.

The results show that the nature of psychiatric manifestations cannot be generalized across all patients with HD for several reasons:

1. 1) in the course of HD, symptoms change spontaneously reflecting the degenerative pathogenesis of the disease;

2. 2) the phenomenology of symptoms depends on age of onset, patient's gender, number of CAG triplets, gender of the affected parent;

3. 3) drugs used to improve motor symptoms have psychiatric side effects which superimpose and merge with the mental abnormalities of the disease;

4. 4) Huntington’ gene is just one of the 30,000 expressed in the brain.

Therefore, the symptoms induced by the disease depend not only on the specific abnormal gene causing the disease but also on patient's general genetic background of both paternal and maternal origin, and on personal non genetic factors.

Rather than standardized approaches, the continuous re-evaluation of psychopathological dimensions in the individual patient with HD is essential for the proper management.