Additional Study Information: The purpose of this research study is to find out whether a new investigational drug called SRX246, which might be useful to Huntington's Disease (HD) patients who sometimes feel irritable, angry, or even aggressive, is well tolerated and safe when it is given two times a day by mouth at doses as high as 160 mg. As part of this study, we will use a number of questionnaires because we want to find out how much we can learn about how you feel based on the answers you give. This will let us and others plan future studies of medicines that may help HD patients control their temper better. This study will compare SRX246 to placebo. The placebo looks like the study drug, SRX246 capsules, but contains no active study drug. You will have a 2 out of 3 chance of being assigned to SRX246. You will have a 1 out of 3 chance of being assigned to placebo.