Anxiety and Depression in my opinion are not natural emotions that come in cycles. I never had them when I was a child and only developed them when I became ill. My boyfriend never gets that way except for a little anxiety perhaps when his blood Sugar is too low...he has diabetes. In my opinion, anxiety and Depression manifest due to illnes or situations where the emotions have become tramatized.
I was really ill the last two weeks and my thoughts were anxious and I was depressed. I am feeling better physically and mentally the last two days and thinking about the same things that caused me anxiety last week are not causing me anxiety today. but when I get ill again, my thoughts will become anxious again. It is not something that I just feel through and it will leave in a day. I have gone through this for years and riding the wave does not make it go away. To me it is like comparing it to seeing a wart grow on your hand and saying, oh it is just a wart, I will feel through this and it will go away. The key is to find out the cause and deal with that.