Doctors do this all the time (not purposely but with the best intentions) but we don't recognize it. When a doctor gives someone a set time to live and right to the very day it was told that person dies.

I'll tell a story of someone I once read, this is from my memory so it wont be exact but the main details will be there. I heard it said something like this, an American was visiting Tibet and highly offended a monk (this seems unusually given their spiritual nature but I do remember it was Tibet so i believe someplace something was mixed up but I'll continue now) The monk said to the American "I give you one year to live!" The American scoffed at this idea, yet one year to the day he developed something that killed him.

Here is how this worked, this thought "could that have been a real curse" was in the back of his mind to stew over for an entire year, it was a deep subconscious thought possibly not even consciously believed in but the seed of poison was planted. Hence as one year came closer and closer this poison came to the surface worry over could that have been real?

My dad knew a guy that was told from a doctor he had like it was maybe eight months to live, the guy went home and marked it on his calendar exactly eight months to the day his dying day, then he counted down every day marked off until he reached that day and died on that very day.

All a curse really is is planting a seed of doubt, "could this be real?" But it has to have enough time to really take affect so that the person creates the curse they believe they have been cursed with. For a skeptic to be cursed it has to be like a year maybe two maybe ten years, so that they long forget about it but our subconscious remembers long after we consciously forget. This is why hypnotherapist find the root of many problems come from something said in childhood long forgotten. The only different is then it is not intended as a curse but just to be mean to you then, but it ends up the same thing a curse hidden in the back of your mind you created as a result of something you were told as a child. This could be something like "You are bad, you are a trouble maker, you'll never amount to anything great!" Believe it or not that is a curse, who ever said that just planted a poison seed that that person is responsible for, that belief that you are bad follows you through life and keeps you down, the person that told you that has his own karma to answer for and yours now plus any one you hurt through believing you are bad as you were told.

That is why Jesus said there is a huge responsibility being a teacher because you are held accountable for all you influence whether for good and you are rewarded or for bad and you are cursed for.

James 3:1 Not many of you should presume to be teachers, my brothers, because you know that we who teach will be judged more strictly.