Symptoms

"Manic-depressive insanity…includes on the one hand the whole domain of the so called periodic and circular insanity, on the other hand simple mania, the greatest part of the morbid states termed melancholia"
-Kraepelin

The symptoms of MDI can be extremely variable from person to person, remaining fairly consistent over time in the same person. Some will experience both Mania and Depression. Others only or mostly Mania, Depression, or Mixed States.

MDI is an illness affecting energy level and mood. Mood and energy changes occur often but not always in the same direction. In general, Mania manifests as an increase of energy with cognitive and physical activation, while depression usually results in decreased mental and physical activity.