I once quit caffeine cold for 6 months: 2 weeks of pure hell then it was like I never craved it until life got real and stressful and I fell off the wagon. Today, I drink my espresso with a dot of lowfat milk now and life is currently too real and stressful to consider trying to drop it again. I do suspect some of us likely have undiagnosed low-level mood disorders leaving us highly functional but discontent and caffeine is the spackling compound used to plug the hole in our souls.

I stopped drinking coffee for a month and didn't notice any difference in my anxiety/mood/etc, so I returned to my regular schedule (3-4 large cups in the mornings).

I quit caffeine for a year but it didn't work out for me. I felt mentally sluggish all the time; there would be times I'd be staring at my screen with my mind resisting the act of processing any information. I also noticed I became very sensitive with how much sleep I got, and if it was anything less than 8 hours the day would be miserable. I could be a special case here with altered brain development since even as a small child I was drinking liters of black sun tea. So since my withdrawal experiment I've highly regulated my caffeine intake with pills with a maximum of 200mg a day before noon, although I will sometimes cut back to 50-100mg a day during periods when my life isn't running full steam. This has worked out well for me.

When work was chill I went to decaf for the morning espresso on weekdays, and enjoyed real coffee on weekends. I took glee in withholding energy from work that I redirected to my personal time.

Then when work picked up, I went back to regular coffee everyday.

I don’t think there’s a hole in my soul though. And caffeine degrades my personality a little bit (to my own judgment).

Caffeine (like all stimulants) can alleviate symptoms of various dopamine-related disorders, like ADHD. I'm sure many people are self-medicating.

This study considers caffeine concumption outside of coffee, so an alternative caffeine source might be worth looking into. That was my takeaway, at least. I also drink espresso, for the caffeine and the noticable ease on my gut compared to drip or pressed coffee.