I don't do DPH but I'm kind of a pharmacology whiz, it's what got me into using drugs in the first place actually.

To the point tho: Caffeine as most of you know, acts as a counterfeit Acetylcholine. Most of the effects you feel on DPH is actually your lack of Acetylcholine caused by the drug. If you drink Caffeine regularly and then stop for a few days; your Acetylcholine will be lower than normal, combined with the missing factor of Acetylcholine levels being lifted by consumption. I tested this out, being a heavy drinker of morning coffee. Here's my personal findings: The first time I took it without stopping my intake of caffeine. The 300mg had the typical effect of making my body heavy, my mind slow and my vision filtered strangely, (300mg does not get me completely tripping.) The next week, I quit coffee. Generally, the impact of withdrawal is at its highest on the 3rd-ish day depending on the individual. 300mg taken, followed by a noticeably more intense come-up with my hallucinations being similar to a 450mg trip. Shadows behaving like sentient beings, static filter. Basically my brain unable to properly decipher its physical environment.

I should clarify this test was done only once so other miscellaneous factors cannot be ruled out.