The nocebo effect is the negative reaction experienced by a patient who receives a nocebo. Conversely, a placebo is an inert substance that creates either a positive response or no response in a subject who takes it. The phenomenon in which a placebo creates a positive response in the subject to which it is administered is called the placebo effect.
Both nocebo and placebo effects are entirely psychogenic. Rather than being caused by a biologically active compound in the nocebo or placebo itself, these reactions result from a subject's expectations about how the substance will affect him or her. Though they originate exclusively from psychological sources, nocebo effects can be either psychological or physiological.
Superman in other words, cause most of the Krypnonite effect, this explain how Batman could use a ring against him, why he the red sun light takes his powers.
Clark fears kryptonite and the red sun to the point, he loses his power faster that he should.
1. Superman gets his powers from the yellow sun rays, still if you use anything that make him belive the Sun is Red or you use Red Light Superman start losing his powers, even when is not real red sun rays.
2. Kyptonite work because it poisons Superman with his radiation faster that humans, still you notice that when he is around kryptonite he loses is power not in seconds, in the exact moment he gets expose to this, if this was the truth, human would had the same problem, still it looks the radiation would take years to actually poison a normal human, even when radiation can hurt Superman, you notice this radiation hurts him faster that any other type or radiation.
Clark fears this thing because nothing can hurt him, heck he could be immortal for all we know, since this are the only few things that can kill him or hurt him, his mind and body reacts to them faster that they should, this is based on the fact he fears them, that explain why he dont have to see it, just the fact he feels the radiation or the rays, it makes his subconscious act again himself.
This explain why Batman keeps using the ring and not a body armour made of Kryptonite, as long as Clark is afraid of this, dont matter how much Kryptonite he uses, Clark is his own worst enemy.