I took a high dose for years. Then I started having symptoms such as difficulty moving, etc. My primary care doc said I evidently had built up a toxic level in my body and took me off of it. The symptoms went away and haven't returned. One pdoc wanted to try me again on it, but I refused, to his great anger. I am now scared of it. As someone said, try not to take too much. It tends to seem like a mild drug, but some bad long-term side effects can evidently develop. One pdoc I heard about no longer precribes it, but it is used very frequently as a mood stabilizer by many pdocs.