Kay Jamison explains that bipolar illness is characterized by extreme changes in mood, activity, and sleep, and elevated irritability.

Bipolar illness is characterized by extreme changes in mood, activity and sleep and energy. One of the things that is very characteristic of all of the states of bipolar illness is elevated irritability. So people tend to be very irritable when they are depressed and when they are manic. Their mood when they are manic often is very elevated, high, euphoric and expansive but sometimes it’s just very irritable and very paranoid. When people are manic they have a lot of energy, they don’t need to sleep as much, their judgment tends to be very impaired, they tend to engage in activities that are wildly inappropriate. Lots of energy, lots of ideas; a chaotic, often dangerous state. Dangerous to the person involved, sometimes dangerous to other people. In the case of depression the mood tends to be again very irritable, depressed, flat, disinterested; so people that are ordinarily very interested in certain things lose their interest in these things. They slow down. It’s like the entire metabolism changes (the brain metabolism as it were), people don’t have the kind of energy they used to, they lose interest in the world around them and they will sleep too much or not be able to sleep well. Both of these disorders are fundamentally disorders of sleep and energy and mood.

bipolar disorder, symptoms, mania, depression, high, low, irritability, sleep, activity, kay, redfield, jamison