Fluoxetine in the treatment of Huntington's disease

Recent reports suggest the possible efficacy of selective serotonin reuptake inhibitors (SSRIs) in treating particular symptoms of Huntington's disease (HD), such as aggressiveness and agitation. However, predictive features to identify HD subjects who may benefit from this treatment have not been established.

Two individuals from a large HD pedigree with a very high prevalence of obsessive-compulsive disorder (OCD) have been treated with fluoxetine, an SSRI. We aimed at testing whether the co-occurrence of the two disorders in this pedigree might have some underlying pathogenic similarities, maybe also resulting in a good response of HD symptoms to the anti-obsessional drug fluoxetine.

Each patient was evaluated, started on fluoxetine treatment, and then reassessed monthly with: (a) the HD motor rating scale, to rate the impairment of movement, and (b) the mini mental state examination, for a cognitive ascertainment. They had a complete psychiatric and neurologic examination as well.

Both subjects showed an excellent response to fluoxetine. One patient exhibited improvement of the motor and behavioral components of the disorder, while the other improved also in the cognitive domain of HD. The best response was shown by the individual suffering from OCD in her youth. The amelioration in these two patients has been maintained for 2 and 6 years, respectively, whereas the course of HD is that of a progressive deterioration.

Firm conclusions to explain these results cannot be drawn. However, a hypothetical involvement of the serotonergic system, suggested by the excess of OCD in the pedigree, seems supported by the response of these two individuals to fluoxetine. It may be worth further exploring the value of the psychiatric picture in selecting the appropriate treatment for at least some cases of HD.