Moving south, if feasible, sounds like a way to reduce seasonal depression.

However, I have no experience with moving south to reduce seasonal affects of depression or BP. I use light therapy among other things to cope with it.

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Seasonal Affective Disorder (SAD) and Seasonal Bipolar Disorder both occur and may require different treatment, though it seems they are not easy to tell apart:

* SAD: Is seasonal affective disorder a bipolar variant? | MDedge Psychiatry

* How Seasonal Depression Affects Bipolar Disorder | Everyday Health

* Seasonal Affective Disorder (SAD) - HelpGuide.org