(copied straight from Wikpedia)
Mania, also known as manic syndrome, is a state of abnormally elevated arousal, affect, and energy level, or “a state of heightened overall activation with enhanced affective expression together with lability of affect.” Although mania is often conceived as a “mirror image” to depression, the heightened mood can be either euphoric or irritable; indeed, as the mania intensifies, irritability can be more pronounced and result in anxiety, or violence.
The symptoms of mania include elevated mood (either euphoric or irritable), flight of ideas and pressure of speech, increased energy, decreased need and desire for sleep, and hyperactivity. They are most plainly evident in fully developed hypomanic states. However, in full-blown mania, they undergo progressively severe exacerbations and become more and more obscured by other signs and symptoms, such as delusions and fragmentation of behavior.
I would like to write more on this topic in the future.