This study will evaluate the effectiveness of 1-octanol, a substance similar to alcohol but less intoxicating, for treating essential tremor. Essential tremor is an involuntary shaking, usually of the hands, for which there is no satisfactory treatment. It affects about 1.4 percent of the general U.S. population, with the figure climbing to nearly 4 percent among people over 40. Results of two previous NIH studies have shown 1-octanol to be promising as a potential new treatment. This study will test the effectiveness of 1-octanol on essential tremor at doses lower than those given previously.

Patients 21 years old and older with essential tremor may be eligible for this study. Participants are admitted to the NIH Clinical Center for two treatment periods of 1 week each, with a 1-week break at home between treatments. Before beginning treatment, participants undergo a medical history, physical examination, blood and urine tests, and an electrocardiogram (EKG). In addition, tremors are measured using accelerometry, a procedure in which a small device, mounted on a piece of cardboard, is taped to the patient's hand for about 30 minutes.

Patients are randomly assigned to one of two groups. One group takes 2 to 4 capsules of 1-octanol 3 times a day for 1 week, followed by a 1-week "washout" period (no treatment), and then 2 to 4 capsules of placebo 3 times a day for 1 week. Following the same dosage schedule, the second group takes placebo the first week, followed by the washout period and then 1-octanol treatment. Blood pressure and pulse are measured at 15, 30, and 60 minutes after the first dose of the day and then 3 times a day each day of hospitalization, EKG and blood draws are done every other day during hospitalization, and blood is drawn again 1 week after the end of the study. Patients evaluate their tremor daily according to a tremor scale and are also rated according to an alcohol intoxication scale.