Spiraling from Yang to Yin to Yang
In Chinese medicine, bipolar is a range of Mind-Body-Spirit disorder, Dian is a Yin manifestation, tending from deficiency, and manifesting as depression and withdrawal; While Kuang, or mania, belongs to Yang patterning, and manifests as full agitation.
Prolonged withdrawal [Dian] leads to phlegm depression transforming into fire, which results in mania; While prolonged mania [Kuang] leads to insufficiency of vital Qi, resulting in withdrawal. Dian and Kuang, in their extremes, are always inter-related; transformative aspects of Yin and Yang.