after i answered you and quoted a paragraph from a site i touched by mistake the button abuse so i apologize for that. again it's
http://www.ehow.co.uk/about_5078742_can-cause-hand-tremors.html
it mentions many reasons for hand tremors so it's really difficult here to differentiate. for instance my father who is 67 has them when he sits to pray his right hand trembles a bit but he neither takes lithium, nor any neuroleptics yet he has a little of ms like any old age person. Usually parkinsonism is manifested not only in hands but short walking steps so it isn't only hand tremors but also slow movement, impaired speech or muscle stiffness — especially resulting from the loss of dopamine-containing nerve cells (neurons). for a person though to have ms he suffers changes in sensation muscle weakness, muscle spasms, or difficulty with coordination and balance problems in speech or swallowing ( i myself have this last one lately I doubt i have ms) fatigue (everybody has it) varying degrees and emotional symptoms of depression
Also long treatment by lithium can lead to hand tremors so frankly this is a question you should direct to a neurologist ONLY him knows the differential diagnosis between ms, parkinsonism or other reasons. He will ask you of course if you take medications especially for psych illness like neuroleptics or lithium etc...neurologists are aware of psych problems too and know the medications they write
good luck
Although long treatment by lithium can lead to hand tremors but frankly this is a question you should direct to a neurologist only him knows the differential diagnosis between ms and parkinsonism.
Hand tremors happen for a variety of reasons. Caffeine or alcohol might cause the shaking, as will alcohol withdrawal. Stress from work might contribute, or it might just be part of the aging process. Yet the cause may be more serious, indicating Parkinson's disease, multiple sclerosis, thyroid disorders or low blood sugar. In addition, hand tremors can be caused by medication taken for another problem altogether, so it's important to consult with a doctor about any medications being taken.
See your medical doctor too. If it is ms or parkinsons' then it is not a psychiatric problem but a general medical problem.... it could also easily be some other medical problem.
Speak to your psychiatrist about this. Short term movement disorders can occur as a side effect from some medications and this is treatable with a side effect pill within a psychiatrist's clinical discretion. If any movement changes have worsened over time or changed in how they occur your psychiatrist might want to refer you to a neurologist who is a movement disorders specialist to rule out the potential of any long term movement disorders so they could be identified and treated.
Tremors can also be caused by some medications. Maybe you should review the side effects of the medications you are on also.