Dear Teresa -- 
Usually, in my experience, people with bipolar disorder are using marijuana because it helps control their mood (usually the agitated, irritable, going-too-fast symptoms).  Can that interfere?  We don't have good information about your question from research studies.  Again just speaking from my experience, people who get on an adequate dose of mood stabilizer (and often it takes more than one; usually needing Ativan is a marker for needing more mood stabilizer, in bipolar disorder) seem to give up the marijuana -- as though they had found something that worked better.  

Dr. Phelps