I keep forgetting to consider that my changing biology could be a factor in my irritability. Most of my adult life, I could have as much coffee as I liked. A few weeks ago I started getting the jitters if I had more than two. Last week I got the jitters after only two. So now it’s one. Will it soon be zero? Could the jitters be related to irritability? Could my symptom be a physical one rather than a spiritual one?