Q. I have a 15yo son who is being treated for possible cyclothymia. He is taking 600mg of lithium in the AM and 900mg at night. Even though he has been on this for several weeks there has been no change in his actions but also no side effects from the lithium. His Dr. says that this means that his brain chemistry is in need of something but is not certain what is going on. (He says there should be side effects at this level) What are the possible alternative diagnosis and treatment? He has most of the symptoms of cyclothymia but has never had any true mania or depression.

  A. Not having side effects is a good thing, if the medication is the right one. There actually are a number of folks that have few, if any, side effects to lithium. Hopefully your son is one of these folks. Most of them only need to have thyroid function followed every 6 or 12 months because of lithium's effects on the thyroid.

The more important question is whether the medication is the right one for your son. Lack of side effects is great, but no guarantee the medication will work or is the right one or his brain needs it. Other than checking a level of lithium, (should be at least 0.5 mEq), you may have to wait. Lithium takes time to work. Another 4-6 weeks may be needed.