Apparently, the biggest reason for bipolar people to not take their meds is Anosognosia, or being unaware they (we!) have an illness. It comes into play when an episode happens.
… anosognosia is thought to be caused by damage to the brain, particularly the frontal and parietal lobes of the brain’s right hemisphere. The right hemisphere of the brain controls thinking skills, and damage can result in a number of problems, including difficulty with reasoning and problem solving.
From my initial reading, I gathered that the most serious consequences of not being treatment compliant were rampant episodes plus an increased chance of suicide, but there’s a whole lot more. Basically it boils down to the fact that dear old bipolar (insert hollow laugh here) can be progressive.
The consequences of untreated bipolar disorder:
Future manic and depressive episodes will be harder to prevent.
The disease can worsen with time without consistent treatment, meaning that the intensity and frequency of manic and depressive episodes will continue to increase over a person’s lifetime.
Most likely it will be harder to function consistently in various areas of your life, such as school, work, family and peer relationships, or participation in extra-curricular activities without continued treatment.
No meds means a doubled chance of episodes, an increase of depressive over manic episodes and the possibility of developing rapid cycling bipolar disorder. source
I also posted info recently, about the increased health risks and brain damage associated with bipolar, all of which can occur unchecked if medication is not used. The fact that stuck with me most is that it shrinks the hippocampus (see image).
It used to be thought that if you had bipolar disorder, you would return to normal in between mood swings. We now know that this is not so for many people with bipolar disorder. You may continue to experience mild depressive symptoms and problems in thinking even when you seem to be better. more
Natasha Tracy, as ever, has a quality post. This one is about treating bipolar without meds.