[Sarika]

There is a form of bipolar that does switch quickly, it's called rapid-cycling. It's not "technically" a diagnosis, becuase some psychiatrists argue that it doesn't exist. Despite if it exists or not, it's an extreme switch - and it's not caused by external stimuli. It's more common in younger children, which is the main reason why there is the dispute (children naturally have funky emotions and moods).