Learn English – A word to describe the state of forgetting something

In psychology, it is called doorway effect or location updating effect.

Researchers already know that walking from one space to another makes people more likely to forget tasks when compared to others who don’t make such a transition. Called “location-updating effect” the phenomenon also causes people transitioning between rooms (even virtual ones) to take more time while attempting to recall items from memory.

news.discovery.com

It happens both in virtual and real environments; and it is explained that leaving a place and entering a new one is served as an event boundary in the mind and memory refreshes itself for the new information.

This “doorway effect” appears to be quite general. It doesn't seem to matter, for instance, whether the virtual environments are displayed on a 66” flat screen or a 17” CRT. In one study, Radvansky and his colleagues tested the doorway effect in real rooms in their lab. Participants traversed a real-world environment, carrying physical objects and setting them down on actual tables. The objects were carried in shoeboxes to keep participants from peeking during the quizzes, but otherwise the procedure was more or less the same as in virtual reality. Sure enough, the doorway effect revealed itself: Memory was worse after passing through a doorway than after walking the same distance within a single room.

scientificamerican.com

Bipolar seems to best suggest switching between extremes along the same line or element, the association with mental illness is a consequence of the word bipolar being a good fit because depression and mania are considered polar to each other, like north and south poles in the axis of the earth, etc. Common usage like applying it to mental health does not eliminate the function of the base word, no more than than the issue of being gay has taken on additional meaning over time.