Did Lincoln Have Bipolar?

Reading Donald's biography on Lincoln made me think that Lincoln may have suffered from bipolar disorder. The descriptions of his cycling from depression to extreme productivity seemed like almost a textbook example of bipolar disorder. From what I know about the disorder, people in the mania stage are often extremely productive, charismatic, and take on new tasks. These qualities are valued in society, so people in mania often go undetected of any issues. The extreme swinging from depression to what seems like mania described in the biography really stuck out to me. I guess there isn't really any evidence to suggest that Lincoln suffered from anything so bad that it kept him from functioning, but I think he may have had mild bipolar.