A switch in moods can happen both slowly over time and shortly within a day or hours. Mania usually happens quickly, with triggers seeming to be stress, usually interpersonal, or focusing for too long (over 4 hours) on something I'm working on. Getting to euphoria happens when the mania lasts a good long while, like months. Long-term depression seems to just happen and I'm not aware of it until I am and my therapist confirms. Short-term depression usually comes on due to a specific trigger, anything that is bad or reminds me of my worst moments of not wanting to live. I can rapid cycle between short term mania and depression while in a long-term trajectory of mania or depression.