My New Speculation on the Sundowning Phenomenon

In Beating the Dementia Monster, I commented on mild depressions I was experiencing in 2015, 2016, 2017, and perhaps later.  They would begin in late afternoon, but disappear in the later evening.  During my diagnosis, my doctors asked me a number of questions suggesting they were investigating my reports as sundowning.  They never concluded anything, but I'm convinced this was sundowning.

Originally, the depressive episodes occurred four or five times per week, but became less frequent when I began changing my exercise, diet, and other habits.  To my recollection, they did not decrease in intensity, but they became less frequent as I proceeded with implementing the Dementia Toolkit.  After six months, they occurred something like twice per week; and after a year, once every two or three weeks.  Or so I recall.  It seems that during 2017 they might occur once every couple of months.  At this point, it's been several years since I had an episode.

In Beating the Dementia Monster, we discussed the conventional medical hypothesis that changing shadows late in the day cause confusion among the elderly with dementia.  But I haven't seen this explained as proven fact, and, quite frankly, I reject it.  I said that during one of the worst periods of my experience, we traveled to Alaska during summer.  At 9 p.m., the sun was still high in the sky, and I didn't experience an obvious period of "changing shadows."  Nevertheless, I experienced the depressive episodes according to the same timing as back at home.  As near as I could tell, the experience in Alaska was identical to what I experienced at home.  I speculatively concluded that the timing of the episodes was more associated with my circadian rhythm than environmental factors. 

What may (or may not) support my speculative take on this is this article referred to me by my friend, Teale.  We've written several times about new methods for diagnosing Alzheimer's disease, including blood tests.  The article refers to some new research from the University of Surrey in the UK exploring some of these blood tests.  The tests, of course, look for proteins and other chemical biomarkers for Alzheimer's disease in the blood.  What the researchers were surprised to discover is that the biomarker concentrations varied with the circadian rhythm and were highest in the evening ... right when sundowning occurs.  So ... something we don't understand about Alzheimer's disease varies according to the circadian rhythm.  For some reason -- without a clear cause and effect relationship -- both chemical activity and depressive episodes vary together.

Now I am making this connection all by myself.  From what I can see, no one has tried to connect this phenomenon in blood tests with sundowning.  But for me, it makes a lot more sense than the changing shadows hypothesis. 

BTW, here's a picture I took on our trip to Alaska.  I kind of like it.