Here's the latest from the medical literature:
1. There are studies on marijuana and PARKINSON's tremor, but none that I saw for essential tremor.
2. Although parkinson's tremor and dementia do overlap with alzheimer's disease, I haven't seen anything that shows essential tremor is a risk factor for developing Alzheimer's.
Have you tried Mysoline (primidone)? It's an antiseizure drug that's been very helpful for essential tremor, but it makes some people sleepy.
As far as the surgeries go, there's thalamotomy where they make a cut in a part of your brain called the thalamus, a major relay station for many neurological functions. In some patients there is a marked reduction of tremor, but there are a lot of side effects as you can imagine.
The other surgery is deep brain stimulation, which is done here at the Cleveland Clinic by Dr. Rezai, an outstanding neurosurgeon. A tiny electrode is placed in your thalamus to stimulate it which can be controlled with a small manual device that is external. In one study, 80% of patients with essential tremor reported marked to moderate improvement in their daily activities. But with all things, there are side effects such as infections. You need to talk to your physician and neurologist about when is the proper time to consider this, and think about how the tremor is affecting your daily life. Can you write, eat, drink, play sports as well as you'd like? Think about it carefully. Best wishes.