What are the symptoms of atypical bipolar disorder?

Milder ; Reversed. I've read an article that seems to consider this as perhaps milder in the severity of the ups and downs (cyclothymic) than many full bipolar patients and the "atypical" refers to reversed vegetative symptoms - i.e., oversleeping and overeating as opposed to the more common insomnia and appetite loss. I do not know how or if it is treated with different drugs. Be well.
Unsure. Officially bipolar disorder is not described as atypical. Major depressive disorder can be described as atypical when symptoms include increased appetite and sleep rather then the expected decrease.