If untreated, a manic episode usually lasts three to six months.In severe manic episodes, a person can experience psychotic symptoms, where thought content is affected along with mood. They may feel unstoppable, or as if they have a special relationship with God, a great mission to accomplish, or other grandiose or delusional ideas. This may lead to violent behavior and, sometimes, hospitalization in an inpatient psychiatric hospital. The severity of manic symptoms can be measured by rating scales such as the Young Mania Rating Scale, though questions remain about the reliability of these scales.The onset of a manic or depressive episode is often foreshadowed by sleep disturbance. Manic individuals often have a history of substance use disorder developed over years as a form of "self-medication". Hypomanic episodes
Hypomania is the milder form of mania, defined as at least four days of the same criteria as mania, but which does not cause a significant decrease in the individuals ability to socialize or work, lacks psychotic features such as delusions or hallucinations, and does not require psychiatric hospitalization. Overall functioning may actually increase during episodes of hypomania and is thought to serve as a defense mechanism against depression by some. Hypomanic episodes rarely progress to full-blown manic episodes. Some people who experience hypomania show increased creativity, while others are irritable or demonstrate poor judgment.Hypomania may feel good to some individuals who experience it, though most people who experience hypomania state that the stress of the experience is very painful.
Consistent with this, pharmacological treatment of mania returns vPFC activity to the levels in non-manic people, suggesting that vPFC activity is an indicator of mood state. However, while pharmacological treatment of mania reduces amygdala hyperactivity, it remains more active than the amygdala of those without bipolar disorder, suggesting amygdala activity may be a marker of the disorder rather than the current mood state. Manic and depressive episodes tend to be characterized by dysfunction in different regions of the vPFC. Manic episodes appear to be associated with decreased activation of the right vPFC whereas depressive episodes are associated with decreased activation of the left vPFC. These disruptions often occur during development linked with synaptic pruning dysfunction.People with bipolar disorder who are in a euthymic mood state show decreased activity in the lingual gyrus compared to people without bipolar disorder. In contrast, they demonstrate decreased activity in the inferior frontal cortex during manic episodes compared to people without the disorder. Similar studies examining the differences in brain activity between people with bipolar disorder and those without did not find a consistent area in the brain that was more or less active when comparing these two groups. People with bipolar have increased activation of left hemisphere ventral limbic areas—which mediate emotional experiences and generation of emotional responses—and decreased activation of right hemisphere cortical structures related to cognition—structures associated with the regulation of emotions.Neuroscientists have proposed additional models to try to explain the cause of bipolar disorder.