Hypomania is like a manic episode with the volume turned way down. The DSM-4 boundary between mania and hypomania depends on whether the evaluated mood results in serious adverse consequences like hospitalization, dangerous behavior, being fired from a job, getting arrested, wrecking a marriage, or running a relationship.
The most common pattern in Bipolar disorder is for the depressive episodes to be immediately preceded by, or to be followed by, a hypomanic episode.
Hypomania would seem to offer many of the positive aspects of an elevated mood without the serious negatives of mania. You are uncharacteristically self confident and self assured without crossing the line into reckless grandiosity.
Speech is speed up as a compared to baseline, but not to the point where two way conversations become impossible. A greatly increased activity level translates into greater productivity at work, school, or home rather than the exhaustion or agitation accompany mania.
Hypomania also its serious downsides and is a clear signal that Bipolar disorder may lurk down the road. Although you feel just fine, other may find you obnoxious because you are so wired. Your judgement may be impaired what seemed like a fantastic business deal or a very creative short story turns out to be a bust or a waste of time or much worse.
Hypomanic episodes often include hair trigger irritability, with runs of days in which you are consistently impatient and get into arguments over every little frustration. You may get into first fight. This is usually accompanied by sleeplessness and hyperactivity.
Worst of all are the inevitable lows. People tend to crash from hypomania in a fashion that resembles a hangover after a stimulant high and may sometimes progress to a full blown depression. Perhaps most troubling is that some people come to crave the hypomanic episodes and may even stop taking mood stabilizing medication in order to encourage them to emerge. This can lead to an extremely rocky and unstable course.