Background It has been acknowledged that high levels of alcohol use in Huntington's disease (HD) patients is associated with greater ratings of psychiatric symptoms, increased psychiatric symptom progression, and a younger age of HD symptom onset. However, there has been no research investigating the effects of alcohol abuse on the motor and cognitive signs/symptoms of HD and their rate of disease progression.

Aim The aim of this study is to investigate the role of alcohol abuse in the motor and cognitive signs and symptoms of HD.

Methods Using the data of 685 participants diagnosed with HD (58 current-abusers of alcohol) from the European Huntington's Disease Network (EHDN), it was hypothesised that alcohol abuse in HD will cause motor and cognitive signs/symptoms to progress faster and that alcohol abuse results in greater severity of illness.

Results A series of 3 X 2 repeated measures ANOVA's and a hierarchical regression revealed that current-abusers of alcohol had better motor functional ability and better cognitive ability than the non-abuser participants. Both of these effects remained across a three year period. The effect of alcohol on the severity of illness produced a trend, although non-significant, that indicated that alcohol does produce a negative effect on the progression of HD, with alcohol abusers progressing faster.

Conclusions Abusers of alcohol had better motor and cognitive abilities than non-abusers of alcohol. However, there is a likelihood that participants in the current-abuser group were at an earlier stage in the disease.